Prop pitch
Printed From: CorrectCraftFan.com
Category: Repairs and Maintenance
Forum Name: Boat Maintenance
Forum Discription: Discuss maintenance of your Correct Craft
URL: http://www.CorrectCraftFan.com/forum/forum_posts.asp?TID=39131
Printed Date: May-19-2024 at 4:40am
Topic: Prop pitch
Posted By: Peacock
Subject: Prop pitch
Date Posted: June-28-2016 at 6:14pm
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1988 Ski Natique 351w. Right now the boat top speed is 43. It pulls one skier out of the water just fine. Looking to be able to pull 2 or 3 skiers at once. I know more torque means less top end. What I don't know is pitch and shaft size. What pitch prop would give more torque and least amount of top end loss? |
Replies:
Posted By: 8122pbrainard
Date Posted: June-28-2016 at 7:18pm
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Alan, Some more information would be great. At the 43 mph, what's your rpm? What prop is on the boat now? ------------- /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: Jonny Quest
Date Posted: June-28-2016 at 8:31pm
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Usually, you can remove the "castle nut" and cotter pin on the end of the propeller shaft and look at the numbers stamped on the propeller hub. That will give you a good starting point -- along with knowing which propeller that came with the boat from the factory. My own rule-of-thumb is that a good all-around prop size will allow the engine to achieve maximum intermittent RPMs at wide-open-throttle (WOT). Below is the typical information you will need to know when looking at propellers: 1. Engine make/model 2. Name-plate or factory recommended maximum intermittent RPMs 3. Propeller shaft diameter 4. Transmission make/model (direct 1:1 or gear reduction) 5. Engine and transmission rotation The performance you are getting now will help determine propeller options to consider. JQ ------------- Current 2003 Ski Nautique 206 Limited Previous 2001 Ski Nautique Open Bow 1994 Ski Nautique Open Bow Aqua skiing, ergo sum |
Posted By: PROPGUY
Date Posted: November-22-2016 at 7:25pm
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ANY SKI NAUTIQUE SHOULD PULL 2-4 SKIERS OUT OF THE WATER ON ANY GIVEN DAY, MY MALIBU PULLS 8. IF YOU RELLY WANT TO CHANGE PROP PITCH OR CUP CALL OJ OR ACME FOR A RECOMENDATION. AS A OJ AND ACME DEALER I CAN RE CUP YOUR CURRENT PROP OR SELL YOU A NEW ONE AT A DISCOUNT. ROB |
Posted By: 8122pbrainard
Date Posted: November-22-2016 at 7:38pm
Rob, Thanks so much for your advertisement and advice. I'm so glad you have a Malibu and feel they are superior in pulling over a CC. Also, you don't need to use caps as it indicates shouting. ------------- /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 < |
PROPGUY wrote:Posted By: SNobsessed
Date Posted: November-22-2016 at 8:34pm
Some guys like OJ & others Acme. The Acme I bought has better hole shot yet still tops out about the same, as compared to the OEM Federal. ------------- “Beer is proof that God loves us and wants us to be happy.” Ben Franklin |
Posted By: 86ER
Date Posted: November-26-2016 at 11:00pm
| I've got an '86 with the Acme 540 3-blade prop. This prop would fit your boat, as both have a 1" shaft, the same engine, and the same hull. It tops out at about 37 MPH, but will easily pull 3 or more skiers. My understanding is that the wakeboarders prefer the Acme 542, as they run at slower speeds. I suspect that my boat carries a few extra pounds, since the floor and stringers are original, and the foam is probably saturated. If you've got a dry boat below the floor, you may get more speed out of it. With all of this said, I've never had to get close to 37 MPH with someone behind the boat, but then again, I'm towing guys in their 50's. |
Posted By: TRBenj
Date Posted: November-26-2016 at 11:41pm
You are missing 5mph that no amount of wet foam would explain... Time for a tune up. |
Posted By: 86ER
Date Posted: November-27-2016 at 12:13am
| That's with electronic ignition, new cap, rotor, wires, plugs, rebuilt carb, and timed at spec. I would generally add an extra 2+ degrees advance, but it ran well enough without it. It tach'd out at 4600 RPM, and for an engine pushing 1000 hrs, I didn't want to rev it higher. I should have mentioned that the top speed was determined with the single "functioning" speedometer. I did not use a GPS to determine actual speed. |
Posted By: TRBenj
Date Posted: November-27-2016 at 9:01am
I'd check your numbers pretty quick then... Your skiers might appreciate the improved accuracy if your speedo is really reading 5+ mph slow!  Pm me if you need your Airguides repaired. |
Posted By: Duane in Indy
Date Posted: November-27-2016 at 10:43am
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There are numerous I-Phone aps for speedometers. Check them against your boat speedo for an accuracy comparison. Like Tim said, yours is probably off by several MPH. ------------- Keep it as original as YOU want it 1978 Mustang (modified) |