prop size and boat speed 1977 fish nautiq
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=4843
Printed Date: November-10-2024 at 4:22pm
Topic: prop size and boat speed 1977 fish nautiq
Posted By: Buster
Subject: prop size and boat speed 1977 fish nautiq
Date Posted: September-24-2006 at 9:59am
I have been running this boat for 2 years now and since gas has dramatically increased in price, i have been looking for ways to cut my 10gph fuel expense. I think that the boat isn't propped out right since it runs wot @27knots. What are other people getting out of their boats?
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Replies:
Posted By: Buster
Date Posted: September-24-2006 at 1:50pm
| forgot to mention the boat has a 351 pcm with the 1.23 to 1 tranny |
Posted By: nuttyskier2002
Date Posted: September-24-2006 at 2:28pm
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What is your tachometer reading at WOT?
------------- 95 Malibu Echelon w/Mercruiser 350 Magnum Skier Former boats: 88 Ski Centurion Tru Trac II 59 Chris Craft Capri (woody) |
Posted By: Buster
Date Posted: September-24-2006 at 3:21pm
| with a clean bottom, i am reading 4700 rpm |
Posted By: 77stang
Date Posted: September-24-2006 at 6:39pm
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i dont know what those boats should run out at but at 4700 your proped pretty good in regards to rpm. thats a big cut, what do you think itr should run ------------- http://correctcraftfan.com/diaries/details.asp?ID=1360&yrstart=1971&yrend=1975 - '77 Mustang 17 |
Posted By: Buster
Date Posted: September-24-2006 at 6:43pm
| people on the forum seem to get close to 40 mph out of the boat which makes me think that i don't have enough prop on the boat....i do have the tower which gives it a bit more weight but i think the boat should still top out at 35 mph....what do you guys think? |
Posted By: eric lavine
Date Posted: September-24-2006 at 7:30pm
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maybe over the years the engine started to get tired and someone repropped this boat. 27 does seem a little on the slow side for the boat. but your wot seems correct at least within 10%.
if you had a fresh engine then your wot would come up and then allow you to re-prop correctly because now you have the power to spin the prop. I would find out what prop truly belongs on the boat then work from there.if you do find the correct prop and put it on and you only can get a wot of lets say 3500 then you know the engine is tired which means poor fuel economy and poor performance ------------- "the things you own will start to own you" |
Posted By: Buster
Date Posted: September-24-2006 at 7:35pm
| the motor was installed new in late 2001 by the previous owner and has just under 400 hours on it.... it really runs like an animal. Would a 4 blade prop benefit the performance?? |
Posted By: eric lavine
Date Posted: September-24-2006 at 8:15pm
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you might even lower your wot even more, i would think your boat would see an easy 35 to 40 mph.is everything your telling us accurate? something is being overlooked.
Do you have the correct prop? was it a new engine if not who rebuilt it? we need some more info such as what did the boat do before the new engine? please explain in more detail anything you can think of even if you could talk to the previous owner. i personally think something is seriously out of wack. ------------- "the things you own will start to own you" |
Posted By: Buster
Date Posted: September-24-2006 at 8:45pm
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As far as the prop goes, the prop shop said it was correct based on their calculator i think is a 13 x 14 if i am not mistaken. The motor is a pcm 351 installed new in 2001...somewhere around 260hp. I did not own the boat with the previous engine, but the person i bought it from said that this motor has much more power than the last. The boat has an incredible hole shot which leads me to beleive the prop shop was wrong with their calculations and it needs an additional inch or two of pitch. thanks
Michael |
Posted By: eric lavine
Date Posted: September-24-2006 at 9:35pm
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michael,try and find out what the boat came with when new. then we will go from there. one of these guys on this forum should know what prop goes on this boat, did you also switch transmissions when the engine was changed? in 1977 they did not use the 1.23:1 it should have came with a borg warner 1:1 which would mean your prop speed is reduced ------------- "the things you own will start to own you" |
Posted By: jimbo
Date Posted: September-24-2006 at 10:53pm
| Unfortunately, I don't have a fish nautique. But 27 Knots? That's around 32 MPH, right? With a 1.23:1 gear. Plus an eight foot beam plus 500 pounds of fuel plus 3700 pound deep vee hull plus the tuna tower. I think that's about right. The prop sounds right based on the rpm. The people running a fish naughtique at 40 MPH probable have a big block engine. |
Posted By: eric lavine
Date Posted: September-25-2006 at 7:43am
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jimbo, didnt see the knots, a$$umed mph. also claims 10 gph. the boat looks lite, i always compare to similar boats with cabins and to me it still seems on the slow side ------------- "the things you own will start to own you" |
Posted By: GrandSlam
Date Posted: September-25-2006 at 10:44am
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Buster, I just got my ’89 Fish Nautique this May so I do not have a lot of experience on this boat. But here’s what I got, rebuilt PCM 351, stock other than electronic ignition, 1.23 PCM gear, and I cannot remember the prop size, maybe 14x14, not sure here. WOT 4,100 rpm’s @ 37 mph on the GPS. I generally cruise at about 3,000 rpm’s @ 26-27 mph. I was told by a former CC dealer that this is right on for what the ‘Fish’ did new with that set up. AT 4700 rpm you may be a little under propped, at least for what the ’89 PCM manual states (WOT 4000 to 4400). I really cannot relate to the 10gph doesn’t sound too bad especially considering my Jersey burns about 35gph of oil, I have not got a handle on the fuel usage on the 'Fish'. You got a really good lookin’ boat, I love that color, and the leaning post and with the additional weight and resistance of the tower you may not be that far off. Check the max rpm for that year of the PCM 351. What brand of leaning post did you install, I am considering adding one this winter.
Hope this helps, Jerry ------------- Jerry Troy USCG Master, 100GT 1989 23' Fish Nautique 1992 47' Jersey SF |
Posted By: jimbo
Date Posted: September-25-2006 at 11:43am
| 10 gal/hr isn't too bad. Find out what http://www.acmemarine.com/html/contact2.asp - Acme reccommends. Also, have you verified the speed on GSP? |
Posted By: Buster
Date Posted: September-25-2006 at 4:15pm
| thanks for all the info... i think that i am going to just shop around for a bigger wheel for the boat. |
Posted By: michigan dave
Date Posted: September-26-2006 at 8:15am
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Great looking boat!! I have a 84 FN and have been doing some prop research myself. I have the 1:1 tranny but the rest is the same. I even have the identical tower! minus the upper station. I have the opposite problem you have I only turn 3600 rpms but am going up to the high 30's. I am running a 13x14 4 blade acme. I also have a newer motor and its a good runner. Send me a pm I maybe I can help with the prop search.
red71gs@yahoo.com Look familiar??? 
dave. ------------- 1984 Fish Nautique 351ci- 14x13 four blade acme south haven mi. |
Posted By: eric lavine
Date Posted: September-26-2006 at 9:19am
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you guys probably know this but re-propping a boat is science, try calling michigan wheel up in mich and talk to one of their engineers, have all your info ready, hieght,wieght,eyes, you know what i mean.. they have got me out of a jam many times you. try there website ------------- "the things you own will start to own you" |
Posted By: redneck7
Date Posted: September-27-2006 at 8:22pm
| I've got an '82 Fish and I turn 4100RPMs at around 31mph WOT. I've got the T-Top on mine. The engine was supposedly rebuilt 350 hours ago and she's definitely missing some RPMs and/or speed on the top end. I a$$umed mine was an engine issue, but is it possible that I have a mispropped boat as well? |
Posted By: 2_Nautiques
Date Posted: September-28-2006 at 8:23am
Just for reference, I'm running a 13x12 on a Cuddy with a 1:1 and a 350 OMC. WOT is 4300 RPM at 36 MPH on smooth water. This boat has the same hull as the Fish with a little more weight and a place to hide behind when it is throwing spray ------------- http://correctcraftfan.com/diaries/details.asp?ID=1160" rel="nofollow - 1988 Ski Nautique |
Posted By: redneck7
Date Posted: September-28-2006 at 2:27pm
| One thing I learned in short order was that it does indeed throw some water at you. But I like it...I've never gotten on a boat with the intention of staying dry all day... |