Foam vs. No foam |
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eric lavine
Grand Poobah Joined: August-13-2006 Location: United States Status: Offline Points: 13413 |
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Posted: November-24-2011 at 4:38pm |
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your right snob, i just got a plow back from last year which I welded all the gussets where they should be, the plow shouldve been taken out of service 3 years ago, after every gusset there is a crack,
exactly snob your spot on, you re-distribute the weight exactly as you would on a trailer, you must understand hydro theory, when in the water you are redistributing weight and it is equal in the water, its hydraulic theory |
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"the things you own will start to own you"
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SNobsessed
Grand Poobah Joined: October-21-2007 Location: IA Status: Offline Points: 7102 |
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Eric - I agree 100%. If you have a beam design that changes modulus suddenly, that is where the stress concentrates & it will crack there. Hence tapered wall thicknesses & large fillet radii in molded parts. Welds are a good example of a doomed design because they stop suddenly.
Very few structures have infinite life (at max cyclic load). For some reason these factors are not published in the sales brochures. So either avoid epic loading conditions, or don't have the expectation that it will never fail. |
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“Beer is proof that God loves us and wants us to be happy.”
Ben Franklin |
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eric lavine
Grand Poobah Joined: August-13-2006 Location: United States Status: Offline Points: 13413 |
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one would think a 46 foot cougar that does 100 mph hitting 8 ft waves, with 10,000 lbs of engines in the ass end would snap in half, the hull averaged 3/16 across the structure, thin enough to see light thru it. 46 feet long, 8 ft beam, looking out the bow you could see the flex under way, not a drop of foam. normal single stringer design with secondaries...were talking 8 straight hours of brute punishment, to this day i have not seen a boat snap in half.
I look at these cast iron bath tubs (CC's) 19 foot long, built like a tank, if its lucky hitting someones wake is the biggest wave it will ever see in its life. just comparing apples to apples, I really could see the foam effecting more of the structure in a negative way, glass is designed to flex as proven many times when you put a boat in the water.... in the grand scheme if that 46' footer was foamed i believe it would snap in half because you are eliminamiting the flex, alot of you guy's are engineers, and should possibly see this? imagine if you had a rigid air plane wing, you look out that window and see it bobbin up and down, it bobs for a reason, so it doesnt snap off the side of the plane kinda the same theory in a car possibly, you hit a wall in a 68 duece and a qauter your gonna die because of ridgity, now you take a tin can kia with crush zones the car will absorb the sudden stop. so maybe its a double edged sword, flex is definitely considered in a boats design |
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"the things you own will start to own you"
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Swatkinz
Platinum Member Joined: December-03-2003 Location: Lexington, SC Status: Offline Points: 1307 |
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Agree with the above posters, Seb. You are hell on a boat. What's the story with the capsizing?
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Steve
2011 Sport/Air 200 Excalibur 343 2017 Boatmate Tandem Axle Trailer Former CC owner (77, 80, 95, 88, all SNs) Former Malibu owner (07, 09) |
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skutsch
Grand Poobah Joined: June-19-2008 Location: Racine, WI Status: Offline Points: 2874 |
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Seb - I wanna hear the story on how the boat capsized!!!
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Hollywood
Moderator Group Joined: February-04-2004 Location: Twin Lakes, WI Status: Offline Points: 13514 |
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Not to mention cruising in the Vette, BBQs and a handful of Holidays. Busy man!
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charger496
Senior Member Joined: August-06-2010 Location: atlanta, ga Status: Offline Points: 157 |
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Damn, Kapla! With all the prop repairs, capsizing your boat, and having to wipe sunscreen off your seats from all the pretty ladies, it's amazing you have any time to ski!
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kapla
Grand Poobah Joined: March-27-2008 Location: BA, Argentina Status: Offline Points: 6148 |
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My boat capsized once and then when they turn it over it kept afloat with the water to the gunnel level..using a HD water pump that the local CG had aboard they were able to dump all the water and finally towed the boat to the marina....foam I guess saved it from going to the bottom...7 years later due to this accident I had to redo my floors. Should had know the wood thing, I probalbly I would have claimed the insurance the floor repair!! LOL
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<a href="">1992 ski nautique
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GottaSki
Grand Poobah Joined: April-21-2005 Location: NE CT Status: Offline Points: 3362 |
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I don't think one can conclude anything other then if you keep your boat chronically soaked, bad sh|t happens. ponderous.
My noodles are doing just fine since '97. |
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"There is nothing, absolutely nothing, half so much worthwhile as messing around with boats...simply messing."
River Rat to Mole |
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charger496
Senior Member Joined: August-06-2010 Location: atlanta, ga Status: Offline Points: 157 |
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I'm sure pool noodle technology has come a long way recently, what with the advent of....hell, they better be better now. They's in ma boat!
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john b
Grand Poobah Joined: July-06-2011 Location: lake Sweeny Status: Offline Points: 3241 |
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I restored a Glastron Skiflite a few years back (I still don't know why) . The hull was in nice shape, but the floor and stringers were mud. The PO had screwed a sheet of treated 3/4" plywood to the rotten floor with drywall screws that were a little too long. When I removed all the material from this quality repair I found that he had stuffed pool noodles under the floor through some holes he made before he screwed the plywood on top of the rotten floor. The pool noodles were saturated and almost as heavy as concrete. They broke apart under their own weight when handling them. I left a big piece of one out all summer to see what would happen. It only lost a little weight.
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1970 Mustang "Theseus' paradox"
If everyone else is doing it, you're too late! |
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BuffaloBFN
Grand Poobah Joined: June-24-2007 Location: Gainesville,GA Status: Offline Points: 6094 |
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had drifted 4 miles from the boat that capsized and sank
It's a recent story so we'll see if they show or mention the boat. Just saying... Edit-22' Wellcraft Ctr Con |
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Gary S
Grand Poobah Joined: November-30-2006 Location: Illinois Status: Offline Points: 14096 |
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Unfortunately Kevin that old '64 is history.Last winter it started to have starting issues.You have to pull the powerhead to remove the starter.Dad being in his mid 80's just can't work on them anymore or use the pullstart if need be so he took it in and was advised that it was not worth it.That and the fact it was in Florida saltwater now,the wiring was going too.Before I could get it back he had got rid of it.So this spring he found a low hour '03 Mercury 25 up here and he's going to ship it down. |
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bbishop1974
Senior Member Joined: May-16-2010 Location: rindge,nh Status: Offline Points: 275 |
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last night i went down to check on my boat,nice moon lit night,having a frosty adult beverage when i notice something in the water by my neighbors dock.i thought she might have put in her sunfish sailboat.as iam leaving i walk over and notice its the cover to her 18ft stingray in the water.so much for USCG flotation,cover was still on the boat and the boat was at the bottom of the lake.i believe foams only purpose would be as a sound deadner.
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Luchog
Grand Poobah Joined: April-17-2007 Location: Argentina Status: Offline Points: 2135 |
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I have an 80hp Mercury with the blue stripe on my dad's 1978 16' boat. Awesome motor.
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KRoundy
Platinum Member Joined: August-23-2010 Location: Lake Stevens Status: Offline Points: 1702 |
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Gary, I LOVE that old Merc. Nice shot!
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Previous: 1993 Electric Blue/Charcoal Ski Nautique
Current: 2016 Ski Nautique 200 Open Bow |
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harddock
Platinum Member Joined: June-04-2008 Location: Toontown, MA Status: Offline Points: 1763 |
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Anyone ever think of using 2 litre soda bottles? They would last forever, provide flotation, and not hold water if capped. They offer no structural support but noodles can't be much better.
As for the bashing. If it comes from a salesman, it might as well come out of a politition. The crap the reps feed you about how good your product is versus how bad the other guys stuff is usually about 99% bull. |
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Gary S
Grand Poobah Joined: November-30-2006 Location: Illinois Status: Offline Points: 14096 |
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Here's my Dads now primary Florida boat,a '69 Herters.No foam, just bench seats in the shape of an upside down U that also provide flotation. Since you walk right on the bottom,you can see it flex, so much so that it was scarry at first.No cracks in the gel after all these years
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Luchog
Grand Poobah Joined: April-17-2007 Location: Argentina Status: Offline Points: 2135 |
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Greg, my point is from a structural standpoint, the foams add little or nothing, you could fill it with concrete, but it's still unneeded.
How many boats are running no foam and no catastrophic failure occurrs? As Miskier stated these boats are way overdone on structure, specially the old ones, the stringer we are used too see are unthinkable on most other boats. Yes, there's the CG regs and the sound dampening, but that's a whole different matter. probably a composite hull without any foam would sound very shallow on the chop. |
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BuffaloBFN
Grand Poobah Joined: June-24-2007 Location: Gainesville,GA Status: Offline Points: 6094 |
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I gotta go with Tim on this one. I could stand on a chunk of wet foam out of my boat and it didn't give. Also Coast Guard regs? |
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Luchog
Grand Poobah Joined: April-17-2007 Location: Argentina Status: Offline Points: 2135 |
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What keeps the boat in shape is the floor/stringer/hull combo, I dont know why foam is being thrown in the structural discussion.
if you had to build a boat Would you cheap on the floors? Would you cheap on the stringers? would you cheap on the hull? would you foam or not foam? This is the only debatable issue, because i'ts not fundamental to boat building structure. And hulls are ticker on the keel because that's where all the unattached resin ends while laminating!!! Hulls dont need to be rigid, just on certain points, too rigid cracks, some flex points are even good for the structure. And I suggest checking on the newer CCs before talking on other brands lamination, as they have gotten thinner lately. |
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GottaSki
Grand Poobah Joined: April-21-2005 Location: NE CT Status: Offline Points: 3362 |
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When I took my supreme apart, they are not foam filled.
There is a big glob high in the bow, some rigid foam strips just tacked to the inner gunnels, and two strips, like 4x4s under the floor, tacked with glass to the hull. The boat met level flotation standards that way. I have no need for a boat to remain operable after chainsawing a chunk out like a whaleboat or ranger. Its basically rigid pool noodles with glass straps. I added some pool noodles under the floor after removing some foam from the bow for more storage. Now a 70s-80s nautique has glass about twice as thick everywhere. Before foam I believe they are multiple times more rigid than other boats that still perform after 30-40 years . So how rigid is enough? The concept that a nautique is not rigid enough without foam filling is just absurd to me. |
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"There is nothing, absolutely nothing, half so much worthwhile as messing around with boats...simply messing."
River Rat to Mole |
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8122pbrainard
Grand Poobah Joined: September-14-2006 Location: Three Lakes Wi. Status: Offline Points: 41045 |
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Tim, There are times that you are as ADD as I am!! Please note that in my post, I never mentioned stringer issues. It was simply hull thickness and foam adding to the rigidity of the hull!! |
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mdvalant
Grand Poobah Joined: May-06-2009 Location: Bellevue, IA Status: Offline Points: 2059 |
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Our Hydrodyne has rotten stringers and no foam. I think the top shell is the only thing holding it together. But it does look nice!
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TRBenj
Grand Poobah Joined: June-29-2005 Location: NWCT Status: Offline Points: 21182 |
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I gotta disagree with you here, Pete. Soaked or not, foam does lend structural rigidity between the hull and floor. You and I both know that there are many boats running around with rotten stringers, yet somehow they still hold together. Im not sure that would be the case if the only thing holding the boat together were rotten stringers (no foam to keep everything moving together). I dont know about you, but I dont know of any boats that have had their foam removed, then sealed back up with rotten stringers. That seems like a recipe for disaster. A foamless boat (whether the stringers are old or new) is not likely to fail, as the stringers are not likely to be rotten in the first place... so thats not what Im referring to. Like you, Im a no-foam guy because I hate holding water in the structure. I like the fact that foamless structures can drain and breathe- so they should be much less prone to rot. What Im saying above is that if rotten stringers are a foregone conclusion, Id much rather have foam down there holding everything together rather than rotten stringers alone. |
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peter1234
Grand Poobah Joined: February-03-2008 Location: United States Status: Offline Points: 2756 |
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as far as floatation goes I wonder if air bladders under the floor with easy access pressure monitoring would ease the sinking feeling of having no foam
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former skylark owner now a formula but I cant let this place go
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8122pbrainard
Grand Poobah Joined: September-14-2006 Location: Three Lakes Wi. Status: Offline Points: 41045 |
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Mike,
Don't worry about hating yourself for commenting as this subject has come up many times with many opinions and yes "seat of the pants" engineering!! I feel the era (year) of the boat hull makes a big difference. Early glass hulls were thicker and certainly did not need the foam. Then, as years past, hulls were made thinner and the added rigidity of the foam was "engineered" into the hull strength. One thing to keep in mind is old wet foam does not provide any support and to this day, I've never seen a hull fail do to the lack of the added strength of foam. |
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mountaineerminer
Groupie Joined: May-03-2011 Location: Bristol, TN Status: Offline Points: 79 |
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I will hate myself for getting involved in this...
The epic battle between foam and no foam; How does one test hull rigidity as an affect of foam content? Seat of the pants? Can you feel the hull flex at 25 knots or do you just feel the waves beat the hell out of you? I am going on the assumption that the foam does make a difference to ride quality; why wouldent it. Properly installed foam should dampen the impact of the water felt by passengers. Also, in theory it seems filling the void between stringers would increase stiffness. And third, it will help a boat full of water float better. I also dont like the negative of expanding foam, water retention.... Well, I havent settled anything; but I did ramble on about my opinion on foam, and everyone knows what opinons are like. Mike |
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MIskier
Senior Member Joined: July-29-2011 Location: Gulfcoast Status: Offline Points: 144 |
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3X thicker at the keel Every boat that I have dealt with as far as the lamination is concerned has never varied that much in such a short span. Generally it has varied by several layers, never multiples of the hull thickness. |
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2006 MasterCraft PS 190
1986 CC Ski Nautique 2001 |
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MIskier
Senior Member Joined: July-29-2011 Location: Gulfcoast Status: Offline Points: 144 |
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MC dealers and reps do seem to like to do that, and it is off putting to me as well. All of the dealers do it and it varies from sales person to sales person. It has gotten worse as they have added more models and attracted well healed wally's who don't know one brand from the other. Believe me it makes my skin crawl when I read a post about one of these brands and why they are better than another, and the comment is made by a guy whom you know has the dealer do everything to the boat. |
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2006 MasterCraft PS 190
1986 CC Ski Nautique 2001 |
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