How fast is fast?
Printed From: CorrectCraftFan.com
Category: General Correct Craft Discussion
Forum Name: General Discussion
Forum Discription: Anything Correct Craft
URL: http://www.CorrectCraftFan.com/forum/forum_posts.asp?TID=5482
Printed Date: June-09-2024 at 6:04pm
Topic: How fast is fast?
Posted By: backfoot100
Subject: How fast is fast?
Date Posted: January-08-2007 at 7:13pm
| Guys, this may sound really stupid but I gotta ask. I've been reading posts about guys getting 50+ MPH out of their boats. How is this happening? I have to a$$ume that it's the weight and hull dimensions working together as well as engine HP. I know that some of you talk about your Cuda's and Mustang's hitting those speeds and although I know little about them, I have to a$$ume they are smaller boats based on smaller engine sizes but they're still making those speeds. Have the engines been built? I know from experience that there aren't a lot of SN's that I've skied behind that will do much over 40-43MPH and I've been in quite a few of them. Same goes for Tige, MC and about any other tournament inboard. There are newer boats that I've been in that run well into the upper 40's and lower 50's with big blocks or high HP small blocks. My boat does 46 flat out and 44 with a footer in tow and I thought that was doing really well based on my experiences. My brother-in-laws '92 SN will top out at 44 and my best friends '97 SN is a dead heat side-by-side with my boat and he has a GT40. Can somebody please explain this to me? |
Replies:
Posted By: farmer
Date Posted: January-08-2007 at 7:49pm
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embellishments mixed with a couple of rounds of imagination and beers. Farmer |
Posted By: boat dr
Date Posted: January-08-2007 at 9:07pm
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backfoot,this is real easy. the formula of horsepower to weight ratio= speed.There is no magic ,smoke or mirrows,allit takes is money.
300 h.p. in a 2000lb. boat =50 mph How fast can you afford to go????????? My 331 stroker is making an honest 325 hp, how fast will it go,don't know,but it will go 50 + and will use a lot of gas in a short time. It's all about bragging rites,my daddy can whip ypour daddy,big toys for big boys................boat dr ------------- boat dr /diaries/details.asp?ID=4631 - 1949 Dart /diaries/details.asp?ID=1533 - 1964 American Skier |
Posted By: Guests
Date Posted: January-08-2007 at 9:39pm
looking for speed buy a sonic or a skater!....2000+ horsepower
|
Posted By: reidp
Date Posted: January-08-2007 at 9:50pm
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The Doc is in and right on as usual. I've heard no one state that they're late model 2700+ lb boat would run 50+. However, a pre-70 SN weighs 2000lbs and a 70-79 weighs 2100-2200. Back up a few steps and you'll find Mustangs and Tiques at 1600-1700 lbs. I've got one of those with close to 300 HP and if it didn't run 50something one should be scratching their head. Where is 79Nautique when we need him? ------------- ReidP /diaries/details.asp?ID=231&yrstart=1971&yrend=1975 - 1973 Mustang |
Posted By: p/allen
Date Posted: January-08-2007 at 10:06pm
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I have a 16 foot skier with a 220 hp , weighs 1700 lbs runs 47 mph.bone stock
Pat ------------- Pat http://i175.photobucket.com/albums/w146/72ccfan/100_5977-1.jpg - My 72 Skier Rock River Dixon,ILL. |
Posted By: 81nautique
Date Posted: January-08-2007 at 11:37pm
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81 Ski 255hp dead stock except for a EI conversion and an acme 540 ran 48 on the GPS this summer. Bolting on a little more hp some time this winter and hope get to 50 just so I can say it will do it. ------------- You can’t change the wind but you can adjust your sails |
Posted By: 69 Mustang
Date Posted: January-09-2007 at 1:55am
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Fast is good, but I care more about quick. I'd rather be hot out of the hole and up to ski speed as soon as possible. Top speed? eh...I've gone plenty fast in boats, cars and on bikes. These are ski boats, after all. Maybe it's a function of age, don't know.
Dr., still have that 302 kicking around? And I need to order a shaft from you. I will email you in the next couple of days. Thanks. ------------- For every complex problem, there is a solution that is simple, neat, and wrong. "Where the **** are we?" Amelia Earhart. July 2, 1937 |
Posted By: boat dr
Date Posted: January-09-2007 at 8:09am
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Mike, still have a R/R 302, with low hours. It needs a new home,under my bench taking up space.That shaft will require the total length,before we can order.........boat dr ------------- boat dr /diaries/details.asp?ID=4631 - 1949 Dart /diaries/details.asp?ID=1533 - 1964 American Skier |
Posted By: backfoot100
Date Posted: January-09-2007 at 8:22am
| Thanks guys. ReidP, thanks for the input and explaining the weight of those older CC's. I really had no idea how much they were checking in at. All of the boats I've been in have been mid-80's to brand new late models. I know that my boat checks in at about 2400lbs. as do most other boats in that era (mid-80's). Some of the brand new ones are easily pushing 2700+ as you also stated. I understand now. |
Posted By: 79nautique
Date Posted: January-09-2007 at 9:06am
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315hp and 52mph
------------- http://www.correctcraftfan.com/diaries/details.asp?ID=756&sort=&pagenum=1&yrstart=1979&yrend=1979 - 79 nautique |
Posted By: TRBenj
Date Posted: January-09-2007 at 9:28am
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Ive been told that the TSC3 196 (2570 lb) will do 50+ with the ZR6 (375 6.0L) and hydrogate up.
Of the more modern hulls (19'6") I think the 90-96 hull is the "fastest." My uncle had a '95 with a GT40 that would do 50 or so according to the speedos. Its not GPS, but the boat was certainly faster than the TSC1 (GT40) and TSC2 (Excalibur) we've had since then. Increasing weight and decreased running efficiency (to improve ski wakes) probably accounts for the difference on the newer hulls. With my '90, Im still playing with props and dont have GPS, but Id say I was around 47-48 MPH with ~320 hp. I hope to hit 50+ this summer. ------------- |
Posted By: eric lavine
Date Posted: January-09-2007 at 9:37am
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Yeah maybe, if water had a grade to it.
lol eric ------------- "the things you own will start to own you" |
Posted By: quinner
Date Posted: January-09-2007 at 10:14am
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My 05' 206 w/330hp all stock (2700+lbs) will run 46-48 depending on what you are looking at, Perfect Pa$$ or the Speedo. I did GPS the speedos/PP last spring so I a$$ume the readings are close to accurate. The hole shot is very good, we have pulled as many as 4 adults footers at the same time and on my slalom starts I prefer about 3/4 throttle to pop right out. The boat performs very well but I would have more power if it was easily attainable.
------------- http://www.correctcraftfan.com/diaries/details.asp?ID=1143" rel="nofollow - Mi Bowt |
Posted By: reidp
Date Posted: January-09-2007 at 10:52am
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69 - I'm all about the hole shot as well, and if you're able to improve that with engine mods as opposed to a prop change, you'll inevitably receive the freeby of increased top speed as well. So just hammer down and enjoy the G's, and then pull back if you don't want to go any faster, if you can. The desire to go fast just may be a function of age as you mentioned. But are you saying it's the kids or the old farts that want to go fast(?) as I think the fastest "ski" boat belongs to probably our most senior and experienced boating member. Plus Doc and myself have some years behind us too. And while not in contradiction, I first and foremost consider my boats inboard speed boats or runabouts, which have the capacity to and happen to pull a skier now and then. I'd be interested in seeing how members, and esp those with older boats, divide their time between cruising and skiing.
------------- ReidP /diaries/details.asp?ID=231&yrstart=1971&yrend=1975 - 1973 Mustang |
Posted By: quinner
Date Posted: January-09-2007 at 2:00pm
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Young Old Guy (42) Newer Boat (05)
2 seasons we have logged about 140hrs, I would guess 5% of that total is cruising & 95% is skiing in some fashion. Our lake is small, about 220 acres, when not skiing we do more floating than cruising. ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=1143" rel="nofollow - Mi Bowt |
Posted By: 8122pbrainard
Date Posted: January-09-2007 at 2:17pm
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I'm not a marine engineer but even with a mechanical engineering background have always been amazed at how much HP is needed to gain MPH on a given hull. I wish someone could explain it to me in logical terms someday. I do more cruising in my 64 X55 Dunphy and use the 77 Tique for sking. The X55 weighs more and has less HP than the Tique but the X will easily out run the Tique. The old 312 with the side drafts is stock and has never needed any work. It still runs strong and does 54 GPS. The steps in the hull have got to have something to do with it's speed and wonder why Correct Craft never picked up on the concept. I have never skied behind a boat with a flater wake than the X as well. ------------- /diaries/details.asp?ID=1622" rel="nofollow - 54 Atom /diaries/details.asp?ID=2179" rel="nofollow - 77 Tique 64 X55 Dunphy Keep it original, Pete < |
Posted By: jbear
Date Posted: January-09-2007 at 9:16pm
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Middle Old guy (55)-Old boat ('80)
Florida...95% crusin' (can you spell gator) Tennessee.50-50 crusin' to skiing I gotta agree with Reid, as usual, its all about that rush you get when you push the throttle down. john ------------- "Loud pipes save lives" AdamT sez "I'm Canadian and a beaver lover myself"... |
Posted By: dchris17
Date Posted: January-09-2007 at 9:53pm
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My 74 Mustang that I (almost) literally pulled out of a dumpster will do 45 mph, and all I've done to the motor is change the plugs, wires, and oil. ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=917" rel="nofollow - My 1974 Mustang 17 http://www.trooptrack.com" rel="nofollow - TroopTrack : The Best Scouting Software |
Posted By: reidp
Date Posted: January-09-2007 at 9:55pm
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Mr Brainard,
I noticed that you're a fellow ACBS member and found you in the Directory. We try to take part in our local Blue Ridge Chapter. Does this look anything like your Dunphy. I had to read up as I admit I'd forgotten about them and never having seen one in person. Now that's a speed boat! And I'll bet you're right regarding the speed and step hull correlation. I'm gonna get out my Sawzall and cut out some fibergla$$ sections. The X55 I found listed for sale had the 312 like yours and the seller quoted 64 mph!  ------------- ReidP /diaries/details.asp?ID=231&yrstart=1971&yrend=1975 - 1973 Mustang |
Posted By: 69 Mustang
Date Posted: January-10-2007 at 1:47am
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Hi Reid,
42 years young here - 60% ski/40% cruise. The "function of age" comment, for me, is similar to "been there, done that." or "just because I can, doesn't mean I should." As I get on in years, my desire to be the fastest on the river is waning. This may have something to do with where I do most of my boating these days, the upper Potomac around DC. There is more than enough ego and attitude on these waters, I choose not to participate. Don't get me wrong, I am trying to learn how to get the most out of my little Ski Tique, and all the people here are a great resource. And I love to hammer the throttle as much as anyone...sometimes it is down right scary! With regard to is it a ski boat or a boat that is great for skiing - 6 of one, half dozen of the other for me. All of us here love them, and that is all that matters. Thanks for making me think about why I love this forum and my Tique. ------------- For every complex problem, there is a solution that is simple, neat, and wrong. "Where the **** are we?" Amelia Earhart. July 2, 1937 |
Posted By: 8122pbrainard
Date Posted: January-10-2007 at 5:53am
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reidp, Miss X55 has had some engine work and the obvious is the hole the owner cut in the top of the engine hatch to install a 4 barrel carb. Even with lots more HP I would question the 64 MPH he is claiming. Dunphy named the model X55 because they designed a boat to do 55 and mine at 54 GPS is close. I'm really a purest so I don't like what was done to Miss X55. Mostly the color since all of the 45 to 50 made between 1961 and 1965 were varnished hulls with torquise/blue and white vinyl decks and upholstery. The ski club I belonged to in the 60's and early 70's bought one as their tow boat and it served the club very well pulling anything from disks to 9 man pyramids. My kids now ski in the same club in northern wisconsin. Miss X55 has had her bottom fibergla$$ed which is a bad and quick and dirty bottom repair on a wood boat. Don't think about buying it without planing to put on a new bottom. It's interesting that I find allot of the 312 engine owners end up replacing the original side draft carbs with down draft carb. They do this not only for performance but also because they can't get the side drafts to work. The trick is in settig the float levels - you can't follow the Carter instructions since they are for level carbs and with the 312 marine one carb is tilting upward and the other downwards.
I'll have to look you up in the ACBS diectory. It's always great to hear from a fellow member. ------------- /diaries/details.asp?ID=1622" rel="nofollow - 54 Atom /diaries/details.asp?ID=2179" rel="nofollow - 77 Tique 64 X55 Dunphy Keep it original, Pete < |
Posted By: 8122pbrainard
Date Posted: January-10-2007 at 6:28am
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Reid, Are you a new member in the ACBS? I only have my 2005 directory her at work, the 2006 is at home and the 2007's aren't out yet.
ihttp://www.blackhawkacbs.com/DesktopModules/SimpleGallery/SlideShowPopup.aspx?PortalID=0&ItemID=291&Border=White&sb=Name&sd=ASC The above is a picture of my X and what they should look like as from the factory. I couldn't post the picture since I haven't mastered the process yet!! If the above doesn't work, go to blackhawkacbs.com then "pics" then "2002 show" then "page 3" and it will be p0001246.jpg and also the one next to it. ------------- /diaries/details.asp?ID=1622" rel="nofollow - 54 Atom /diaries/details.asp?ID=2179" rel="nofollow - 77 Tique 64 X55 Dunphy Keep it original, Pete < |
Posted By: reidp
Date Posted: January-10-2007 at 8:03am
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Pete, I pulled up your boat and man is that beautiful. The turquoise has it over the red any day in my book. As for the 05, someone, I guess that would be me, neglected to send in my paperwork on time for, so I missed the cut. But we're listed in 06 and years prior, and I JUST paid up for '07 last week.
For unfamiliar CCFAN members, the ACBS is The Antique and Cla$$ic Boat Society, whose mission quite literally is: "...to provide an organization wherein people with a common interest in and love of historic, antique and cla$$ic boats can come together with friends and colleagues in a spirit of fellowship and fun to share dreams, adventures, knowledge, history and experiences." Although we've collectively never put anything in writing, CCFan's vision is strikingly similar, don't you think? Also, the ACBS definitely isn't just for wooden boat guys, and they warmly embrace any vintage boats. I've tried to organize a cla$$ic gla$$ section at our annual ACBS event in the past, which is held every year the weekend after Labor Day. Guess what else is that same weekend this year I just found out? The Orlando CC reunion of course. I can't buy a break. 8122pbrainard's 64 Dunphy 
------------- ReidP /diaries/details.asp?ID=231&yrstart=1971&yrend=1975 - 1973 Mustang |
Posted By: Riley
Date Posted: January-10-2007 at 8:38am
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I'm on a huge lake and would only ever own a small inboard. We do 70% cruise and 30% ski. I liken them to old hot rods with their cla$$ic style, unique ride, and V8 engine with dual exhaust. On my lake, you can tell the sound of an inboard from miles away.
The ACBS in NE hasn't always welcomed fibergla$$ cla$$ics. They put on a great show in Naples, Maine, and the past 2 years there has been a late 60's Mustang in it. About 4 years ago, a friend of mine showed up to the show with a 64 CC American Skier and was turned away, being told it was for wooden boats only. I'm glad to see that they're opening up to old fibergla$$ boats. |
Posted By: 8122pbrainard
Date Posted: January-10-2007 at 8:59am
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Riley, Sorry about your friend being turned away with a "plastic" boat. The ACBS policy is real "gray" on cla$$ic fibergla$$ and it depends on the local chapters. Unfortunatly there are some who only allow wood. Allot depends on available space at shows too.
Reid, Thanks for getting the picture of the X posted. I need to read up on the posts that explain how to do it!! By the way, the X55 only came with the Interceptor 312 "y" block rated at 215 HP. I have been told that the steering wheel Dunphy used was from the last year of the "T" bird that used the 312 which was 1957. ------------- /diaries/details.asp?ID=1622" rel="nofollow - 54 Atom /diaries/details.asp?ID=2179" rel="nofollow - 77 Tique 64 X55 Dunphy Keep it original, Pete < |
Posted By: Riley
Date Posted: January-10-2007 at 9:53am
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8122, I'm just glad they're coming to their senses because they add to the shows, and that's what the old wood boats evolved into.
Heck, new small closed bow runabouts are almost extinct, only 2 in this year's WSM Boat Buyers Guide. |
Posted By: Duck Soup
Date Posted: January-10-2007 at 8:37pm
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In one of my boating phases I was into the speed. As Mr. Brainard asks why doesn't more HP equal more speed. The answer is friction. The amount of hull in the water is by far the biggest deterent to efficient gains in speed. Think about your tow vehicle and how much of the vehicle is actually touching the ground surface, maybe 1-2 Sq. Ft. and then compare that to the drag of your hull going through the water. If you need speed you must elevate the hull out of the water. One of my past boats a 21' Checkmate, 225 HP, 30" clever, most of the tricks of the trade applied. I was radar gunned at 93 MPH. Estimates were that at top speed only 10% of the hull was touching water. So has anyone played with trim tabs with these hulls? That would be the first logical step. Built in hydraulic (gla$$ work) would be the best. Somewhere in my pile of boating gear I have a pair of bolt on fixed but adjustable pads if anyone wants to experiment. I suspect that the hull configuration of the X55 (beautiful boat) is that less of that hull touches the water, sort of like Miss Budweiser. The clever prop on the Miss is probably only about a 13" diameter but it turns at 10,000 rpm!
My 67 Wildcat is 2900 lbs. pumping about 385 HP running 43 MPH at 4100 RPM the 17" pitch prop isn't enough, the tach will approach 4800 so I'm looking at cupping it at least. Weight is a big deal on this hull. Equal thirds on the use, ski, cruise, fish. |
Posted By: eric lavine
Date Posted: January-10-2007 at 10:07pm
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sorry for butting in on the hull discussions and I am far from an expert on hulls, but when we ran on saltwater we picked up 3 miles per hour because of boyancy. I believe alot also has to do with friction, and i mentioned this once before that there was a guy out of England that would apply some type of paint to the bottem of the hull and the boat would see an increase of at least 5 mph the only thing is that it was very pricey, were going back 10 years so i forgot some of the details so what that tells me is friction does have something to do with hull speed.
and with cat type hulls you have the pocket in the middle which has a taper allowing the air to compress somewhat like a funnel and it creates lift making the boat lighter and much faster than your v hull. the steps on hulls also create lift and much less surface area and these hulls typically are faster than flat hulls. Its pretty much give and take, less boat in the water... less stability in the water. this is all from memory and as i said if you feel something i wrote is incorrect ....please correct me ------------- "the things you own will start to own you" |
Posted By: bkhallpass
Date Posted: January-10-2007 at 10:30pm
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Yes, but friction also has to do with the the amount of running surface touching the water.
Boats also get more speed when there is a slight ripple or chop in the water than they do on gla$$y water. BKH ------------- Livin' the Dream |
Posted By: 79Tique
Date Posted: January-10-2007 at 11:57pm
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My 79 Tique (302 Commander) hits 43-44 with a few minor mods. I'm 30 with two kids we ski 80% float some, and cruise a little. Being in the water is where it's at for us. I got a new Acme 542 for x-mas I hoping for more hole shot. ------------- Work to live, not live to work. |
Posted By: 8122pbrainard
Date Posted: January-11-2007 at 6:02am
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Reid, I found you in the ACBS directory. You certainly have a great collection of cla$$ic Correct Crafts. Try to keep pushing your chapter for a cla$$ic fibergla$$ showing. I belong to both the Blackhawk and Glacier Lakes chapters and both don't have a problem with early cla$$ic fibergla$$. We would rather see them than the wood reproductions in our shows. I love the 73 you have in the diaries. Are all your other CC'c in as good and original condition? ------------- /diaries/details.asp?ID=1622" rel="nofollow - 54 Atom /diaries/details.asp?ID=2179" rel="nofollow - 77 Tique 64 X55 Dunphy Keep it original, Pete < |
Posted By: eric lavine
Date Posted: January-11-2007 at 7:38am
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BKH your right about the chop, we always hoped for 2 to 3's in which the boats performed the best. you can even feel this(drag) while waterskiing on a dead calm day, and if you have a little chop you feel alot faster ------------- "the things you own will start to own you" |
Posted By: 81nautique
Date Posted: January-11-2007 at 8:35am
Brian, I think it was Fountain that introduced the step hull to offshore racing and they dominated for a while. They had several steps in their larger boats and it really got the boat free from the surface(tension, drag, friction) not sure what the right word is there but it worked and you'll see those steps on a lot of pleasure boats now. ------------- You can’t change the wind but you can adjust your sails |
bkhallpa$$ wrote:Posted By: boat dr
Date Posted: January-11-2007 at 8:40am
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Eric,i think the word is "Wetted Surface" and Hrydrodynamic Drag, both eat hp at an alarming rate,that is proportional to weight.
After years of racing Hobie Cats,very simple motor,you find that weight and hull drag are our two biggest demons.We are restricted to stock sails and rudders, so all your extra speed has to come from the loss of said "drag" Nothing slides over water any better than water,Hence one of the bottom paints was Outlawed on our Hobies. The product is called Miracle Micro-Baloons, gives the bottom a look simular to an orange. The golf ball princapal only in smaller scale,but gives the same effect to drastictly reduce drag........boat dr ------------- boat dr /diaries/details.asp?ID=4631 - 1949 Dart /diaries/details.asp?ID=1533 - 1964 American Skier |
Posted By: Riley
Date Posted: January-11-2007 at 8:52am
So that be why some people say a waxed bottom creates more drag than an unwaxed bottom? |
Posted By: eric lavine
Date Posted: January-11-2007 at 9:39am
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I thought donzi was one of the firsts to introduce the stepped hull, I can remember them as far back as 1987, the less boat in the water the faster you go as with the hydro's they have air foils on them that the drive controls, because they glide above the surface, with just prop contact to the water. The orange peel does make good sense and as with air im sure it works with water.
This is purely recolection so dont take it seriously if you think its wrong ------------- "the things you own will start to own you" |
Posted By: bkhallpass
Date Posted: January-11-2007 at 10:56am
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See this article - the Historians say that stepped hulls go back as far as 1910.
http://www.vintageraceboatshop.com/SteppedHullDesign.htm - History of Stepped Hulls BKH ------------- Livin' the Dream |
Posted By: 8122pbrainard
Date Posted: January-11-2007 at 12:13pm
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When Dunphy started producing the X55 they got a U.S. patent on it that was called the "balan-stern" stepped hull. There are some drawbacks to the steps. They aren't as manuverable as a flat bottom I think due to the steps dragging in the water on turns. Also all the X55's will ocasionaly at about 7/8 WOT flatten out in a turn to port and go straight!! It can be scarry if you don't know the boat. The theory is that the prop rotation at a certain RPM and the starboard step produces a air pocket so basicly the rudder cavitates. When our ski club had the X55 we had to change the show coarse from counter clockwise to clockwise!! I have installed a slightly larger rudder on mine to eliminate this and I beleave the last production run of the X's had the larger rudders. It's still damn fast! ------------- /diaries/details.asp?ID=1622" rel="nofollow - 54 Atom /diaries/details.asp?ID=2179" rel="nofollow - 77 Tique 64 X55 Dunphy Keep it original, Pete < |
Posted By: reidp
Date Posted: January-11-2007 at 12:13pm
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What Doc said. Additional issues working against our inboard-powerd systems and the quest for speed, are the downward, fixed angle of the shaft, and the inability to trim the drive system up. This downward shaft angle in theory pushes the bow down (a former thread) and increases the drag. Anyone who's operated or experimented with a trim-capable I/O or outboard at full speed witnessed the significant difference in speed between full down and full up trim settings. It can be 7-10mph on a light hull. Trim tabs on a small inboard however typically serve to further bring the bow down and combat porpoising as opposed to lifting it at higher speeds.
I'd always heard a rule-of-thumb formula for trimmable(sp) small outboard and I/O boats of +/-5hp req'd for every 1 mph increase. I've always found this to be somewhat in the ball park. However, this does't apply to our inboards from my experience. I'm thinking somewhere in the 8-10hp/mph, and that's on an older, smallest hull. And unfortunately, I'm confident that the formula or ratio increases, i.e., more hp needed per mph, with the newer boats, and definitely as a function of weigh as stated by Doc. Case in point, my business partner has a cute little '92 Donzi Sweet 16 with what OMC calls a 5.0 HO with only about 220 hp I believe (they don't tell you in the manual). It's carbureted and a 2BBL to boot. Anyway, it weighs 1900lbs and while it's a slug outta the hole, it will still run GPS 47-50 with the drive tucked in, and 57mph trimmed up and trailing a nice rooster tail. These picts were on the StJohns in FL trailing a CC Mustang. 
Pete, our Blue Ridge ACBS chapter completely embraces the cla$$ic gla$$ boats. In fact they hosted the whole Jersey Speed Skiff gang last year which was a hoot. Also there are awards given for non wooden boats. Regarding your question about our CCs, 6 are complete and good running boats, the others are all projects in various stages of completion. Also, I've had several Mustangs that exibited the same "continue straight when turned" scenario you mentioned and ours were normally when decelerating. Scary though. ------------- ReidP /diaries/details.asp?ID=231&yrstart=1971&yrend=1975 - 1973 Mustang |
Posted By: 8122pbrainard
Date Posted: January-11-2007 at 1:45pm
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Reid, The X's would flatten out and go straight after you were into the turn and that's when you usually really needed to turn!! ------------- /diaries/details.asp?ID=1622" rel="nofollow - 54 Atom /diaries/details.asp?ID=2179" rel="nofollow - 77 Tique 64 X55 Dunphy Keep it original, Pete < |
Posted By: Waterdog
Date Posted: January-11-2007 at 2:13pm
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My 78 1600 # ski-tique had a 305 / 198 hp mercruser. Now installing a .030 / 350 Rt rotation engine 9.2-1C/R , 2.02 / 1.60 valves ,410 / 410 cam,4 bolt, DUI ignition,1.6-1 roller rockers, bla ,bla ,bla ect… I talked to Bill Weeks @ acme about a prop. He told me to run the stock prop before buying a new one , he seemed to think 5500 rpm or so the stock prop might be best. The boat should do low 50s. I’ll be happy with low 50s & I’ll buy the prop after the engine is broke in. ------------- - waterdog - http://www.correctcraftfan.com/diaries/details.asp?ID=3896&sort=&pagenum=2&yrstart=1978&yrend=1978" rel="nofollow - 78 Ski Tique |
Posted By: 79nautique
Date Posted: January-11-2007 at 2:49pm
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he told me to use the 540 on mine which was way under proped went with a 470 after finding what the max rpm was first so that I knew exactly how many rpm's to drop down to. With the modes you descriped your going to need a much larger pitch than you currently have. ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=756&sort=&pagenum=1&yrstart=1979&yrend=1979 - 79 nautique |
Posted By: 81nautique
Date Posted: January-11-2007 at 5:18pm
Waterdog, I talked to Bill last week about repropping my boat after some mods I'm making. I'm currently turning 4800 rpm w/ a 540 before the mods and he thought that even .060 cup might not be enough to get the RPMs down after adding some HP. He said to wait til spring as they are currently working on a new 13x14 prop. That may be too much for my boat but sounds like it could be something you should look into. I think it's odd they don't offer a 13x13 yet but maybe thats on the drawing board as well. ------------- You can’t change the wind but you can adjust your sails |
Posted By: reidp
Date Posted: January-11-2007 at 7:57pm
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Guys, I certainly can't claim this as the gospel, but when making mods to an engine that don't involve increased cubic inches, the original sized prop often provides the best performance. An increase in HP doesn't dictate a prop size increase as much as cubic inches and increased low rpm torque do. When you make modifications that result in the capacity to turn higher rpms, you typically also raise the power band and rpm required to demonstrate this new found HP in terms of response and mph. Our main work horse is our 69 Mustang with a multi-staged modified 302/308(.040" over). The original 210HP 302 would spin the original 12x14 prop about 4400 rpm. Step by step we continued to add power until it would eventually turn that same prop 5200. Experimenting with a 1/2 doz props I went up to a 12x15 which dropped the rpm the anticipated 2-300rpm but it also dropped the speed about 1 mph and the holeshot and throttle response were off just a tad. Just for kicks I tried a 12x13 Fed to see if the cam and head combo wanted more rpm, which indeed pushed the rpm to about 5500 and would snap your neck, but it slowed the boat a good 3 mph, basically saying that it pushed it out of its HP making range. So I went back to the 12x14 Fed or more satisfactorily the 12x13 OJ which turns the same RPM. (Note: an OJ prop because of the positive, aft-leaning rake, resulting in more blade area for a given diameter, does not interchange directly with a Fed prop pitch-wise)
I was pleasantly surprised to here what Mr Weeks told Waterdog. While a 540 on many boats really picks up perf, it definitely slowed my light 16 boat turning in the 5000+ range. Waterdog, you most likely have a 12x14 and for a 350 ci it may be a little short on pitch. I will be glad to lend you a 12x15 or 12x16 when you get to the test point. With the mods mentioned, 5500 seems a little high to me also, but it might do it with a 12x14, albeit not with the best perf. If you haven't installed the cam yet and not knowing what your perf goals are, a .410" lift cam is very stock, but not knowing the duration it's hard to say. The good cams being run in most of the Fords on our site here are in the .450-.500" range in terms of lift and 206-225+/- degrees of duration. These by the way are in the neighborhood of and slightly better/higher than what was used in a stock 5.0 HO Mustang car, which wasn't a slouch but didn't behave eractically or have any idle issues. FWIW. ------------- ReidP /diaries/details.asp?ID=231&yrstart=1971&yrend=1975 - 1973 Mustang |
Posted By: 81nautique
Date Posted: January-12-2007 at 7:18am
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Reid,
Good info as usual. End result on my prop situation is we decided to put it back on and see what the mods do before we make any changes. Then we'll call Bill and see what he suggests, probably just a cup job and we're good to go. ------------- You can’t change the wind but you can adjust your sails |
Posted By: Waterdog
Date Posted: January-12-2007 at 8:19am
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Reid -
Thanks for the offer on the prop,I'll take you up on it. I need to get the foam & floor complete. I'm off on monday & plan an all day thrash on it. The engine is a 355 cu.in. chevy .410 cam is 202/213 @ .050 lift - But with 1.5 rockers, I've got 1.6 full rollers with 100 lbs. springs in it . We did the math a couple months ago so my memory is a little fuzzy , I think it ends up .437 valve lift ish ? Performance Marine built it expecting 300 h.p.@ 4800-5200 rpm. 198 hp stock 300 hp now - it should get out of it's own way. Can't wait to get wet in Lake Gaston ! ------------- - waterdog - http://www.correctcraftfan.com/diaries/details.asp?ID=3896&sort=&pagenum=2&yrstart=1978&yrend=1978" rel="nofollow - 78 Ski Tique |
Posted By: TRBenj
Date Posted: January-12-2007 at 8:53am
Your memory is correct. .410 lift with a 1.5 rocker will give you .437 lift with a 1.6. That still sounds like a pretty tame cam for 355 ci. My cam isnt anything wild (.490/.490, 218/222 @ .050), but has a powerband of 2500-5200 on my 351w with 1.6 rockers. Maybe the Chevies are totally different, but I dont see how that cam will make power up to 5200 RPM. Does anyone (ReidP?) know the specs on the stock Ford marine cams? I want to say the 351w was in the neighborhood of .440 lift (stock 1.6), but I havent actually measured my original. ------------- |
Posted By: Waterdog
Date Posted: January-12-2007 at 10:38am
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TRBenj
I'm not an expert on Ford vs Chevy Chevys do like to spin a few hundred rpm,s faster & fords like to pull like a tractor with low end torque. Does the Ford timing chain vs Chevy gear drive have an effect on it ? Do you think 300 hp is in the ballpark. The engine parts are "geared" more for endurance than drag racing. ------------- - waterdog - http://www.correctcraftfan.com/diaries/details.asp?ID=3896&sort=&pagenum=2&yrstart=1978&yrend=1978" rel="nofollow - 78 Ski Tique |
Posted By: reidp
Date Posted: January-12-2007 at 10:56am
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When looking back like thru Chilton's Auto Repair Manuals over the years, and then again this AM thru a 1964-1971 vintage manual I noticed that GM's valve lift specs were generally less than those shown for Fords on similar HP engines. Coincidentally they show a split lift of .390/410 for a 1969-70 350 rated at 300 HP@5000 rpm. The 69 290HP-351 Ford shows a .418/448 lift which is coincidentally the same spec shown in my Holman-Moody manual for that engine as well as the 351-headed 302s. So that cam 'Dog has might get him there afterall, and I'd be confident in the 300HP mark, esp with a nice intake as well. If you'd like one of these neat old full-of-vintage-facts Chiltons manuals, go on ebay and check there. I got two of them for next to nothing$$. I certainly don't memorize all this crap,....er,..I mean, neat stuff. ------------- ReidP /diaries/details.asp?ID=231&yrstart=1971&yrend=1975 - 1973 Mustang |
Posted By: TRBenj
Date Posted: January-12-2007 at 10:59am
I couldnt tell you- my limited knowledge really only applies to the Fords. I would think those mods on a 350 would get you to 300hp though. With intake/heads/cam/DUI on my 351w, I figure I gained ~80, which would put me at 320hp. ------------- |
Posted By: boat dr
Date Posted: January-12-2007 at 11:09am
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Knowledge Is Power............
boat dr ------------- boat dr /diaries/details.asp?ID=4631 - 1949 Dart /diaries/details.asp?ID=1533 - 1964 American Skier |
Posted By: Hollywood
Date Posted: January-12-2007 at 11:13am
Speaking of.... ever find out what Fromunda Cheese is??? ------------- |
Posted By: Riley
Date Posted: January-12-2007 at 11:30am
| I had 2 boats that I tried to make go fast years ago, and it seemed once you reach a certain amount of HP for a certain hull, what you really need then is more rpms to get more speed. |
Posted By: Waterdog
Date Posted: January-12-2007 at 11:51am
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reidp
Intake = Edelbrock Performer (port matched) Holly 600, 198hp vs 300hp 1600# + 50% power gain = Whooo Who !!! ------------- - waterdog - http://www.correctcraftfan.com/diaries/details.asp?ID=3896&sort=&pagenum=2&yrstart=1978&yrend=1978" rel="nofollow - 78 Ski Tique |
Posted By: TRBenj
Date Posted: January-12-2007 at 12:05pm
I imagine youll gain a few lbs going from the 305 to 350, but that little boat will be one fun ride! ------------- |
Posted By: reidp
Date Posted: January-12-2007 at 12:17pm
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Fromunda Cheese?? Hmmm? Bet it goes good served up with a Cleveland Steamer.
I'll use that as a segue(I like that word)to: Has anyone ever seen one of the Cleveland head 351's that Commander marketed back in the mid-late 80's. They called it a Clevor as it used the Cleveland style heads on a Windsor block. I only saw ads on it. They said it made 520 HP and would push a CC 82 mph. Just kidding, believe the HP was only 260. I've never been aware of any other 351-C marine engine applications/conversions from an OEM. ------------- ReidP /diaries/details.asp?ID=231&yrstart=1971&yrend=1975 - 1973 Mustang |
Posted By: The Lake
Date Posted: January-12-2007 at 12:26pm
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Reid,
What rpm's do you run with your 318's, what prop? Don't you have a 318 in a Nautique? If you want, go ahead and talk about valve lift and stuff like that and I'll act like I know what you are talking about 
Chuck ------------- Walk on Water www.coldwater.me http://correctcraftfan.com/diaries/details.asp?ID=775&sort=&pagenum=3&yrstart=1966&yrend=1970 - 69 Ski Nautique |
Posted By: reidp
Date Posted: January-12-2007 at 2:07pm
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Actually a 305 and 350 GM should weigh almost exactly the same. Unlike the 302-351 Ford comp, the GMs are almost completely interchangable with all external dim's being the same. This goes from a 265ci all the way to a 400 small block, right Bowtie boys? If a Tique with 190-230 HP runs 45-50, then 300HP ought to put you mid 50's. I guess I need to go back to my parts bin as I'm feeling an inadequacy attack coming on.
Chuck, As of now we no longer have a Nautique running with a 318, but the two we did both turned a 13x13 prop at 42-4400 rpm, and ran 45 and 47 mph by the speedos. I made up all that cam stuff and no one's even called me on it yet. ------------- ReidP /diaries/details.asp?ID=231&yrstart=1971&yrend=1975 - 1973 Mustang |
Posted By: backfoot100
Date Posted: January-12-2007 at 2:41pm
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ReidP, you're correct about the block size for the small block bowtie although I think the 400 actually has siamezed (sp) cylinders but the block dimesions are the same.
Waterdog, I believe that you are really close for the cam lift that you're thinking for that motor. A .410 lift (or something really close to that) I keep thinking is what a lot of marine cams are from the factory. I have a really good bowtie marine book at home that I'll have to look at this weekend if I get a chance again. It has a lot of good specifics on the parts specs that were used to build different HP engines. I keep thinking that I had a cam picked out that was in the .425 lift range that I want to use when the time comes to rebuild my engine. I want to get a lot closer to 375HP though. I'll let you know what I find out. |
Posted By: Waterdog
Date Posted: January-12-2007 at 5:16pm
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Backfoot100
I'd like to have the P/N for the 425 lift cam for the future .Is it for a reverse rotation engine?I have 2 more 4 bolt (010) blocks , a gear drive timing set, 041 p/n 300hp stock corvette heads.Just waiting to have some money thrown at them.BOAT = break-out-another-thousand. (Don't tell my wife!) I think the 350 weights bit less vs 305 (alum. intake) ------------- - waterdog - http://www.correctcraftfan.com/diaries/details.asp?ID=3896&sort=&pagenum=2&yrstart=1978&yrend=1978" rel="nofollow - 78 Ski Tique |
Posted By: JR_VIC
Date Posted: January-13-2007 at 12:29pm
I'm turning 5400 RPM on the tach and Perfect Pa$$ at about 52.1 MPH verified on Perfect Pa$$. GT40 Heads cleaned up a little, Weiand Intake, Carb with secondary metering blocks, DUI ignition, and my favorite weapon of choice...Hi-Tek headers.  Stock cam at the present time but saving up for a new one from Cam Research.
Thanks! ------------- "That's not a Snow Cone that's my Ring!" |
Posted By: backfoot100
Date Posted: January-14-2007 at 12:24pm
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Waterdog
I was bit off with my memory. The stock 350 comes with around .400 lift. Going with .410 will give you about a 10-15HP increase according to the book I have. That shows a .430-.440 lift for a moderate increase in HP. then a .440-.450 lift for a a 383 or 406 engine. Keep in mind these are 1.5:1 rockers. The .410 lift uses a Comp Cams XE 250 Xtreme energy cam. The .430 lift cam is Comp Cams XE 256 Xtreme Energy and the .440 lift is a Comp Cams XE 262 Xtreme Energy. I'm sure that all of these can be had in a reverse rotaion. Hope it helps. |
Posted By: Waterdog
Date Posted: January-14-2007 at 8:53pm
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backfoot100
The .410 lift cam plus 1.6 roller rockers ends up at.437 total valve lift.I picked these parts for performance and longevity. ------------- - waterdog - http://www.correctcraftfan.com/diaries/details.asp?ID=3896&sort=&pagenum=2&yrstart=1978&yrend=1978" rel="nofollow - 78 Ski Tique |
Posted By: huey
Date Posted: January-19-2007 at 9:09am
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I've had my '96 SN going 70MPH before. Full tank of gas, loaded with gear.
Of course, it was on the trailer at the time.
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