Fish Nautique Prop question
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=5663
Printed Date: November-18-2024 at 7:23am
Topic: Fish Nautique Prop question
Posted By: redneck7
Subject: Fish Nautique Prop question
Date Posted: February-03-2007 at 6:32pm
Just got my new engine installed in my fish...(big $$$  )
Any chance someone could tell me how far off my prop is going to be? I currently have a three blade, which I a$$ume to be original, but I just went from a tired 351W factory rated at 230-240hp to a brand new 350 rated at 320hp. The boat would previously only turn the 351 up to 3900(ish)RPM. How far off am I gonna be?  I know it's a broad/open ended question, but if someone could just point in the right direction (new prop, if so which one? Repitch what I have, if so how do I decide what to go with? Etc). I would like to be able to cruise around 30 at a fair level of fuel consumption (more reserve offshore, the better, but the quicker I get out there...the better).
Thanks, Ryan ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=1620&sort=&pagenum=1&yrstart=1981&yrend=1985 - My 1983 Fish Nautique |
Replies:
Posted By: SkiBum
Date Posted: February-03-2007 at 6:38pm
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Try the Delta Prop website. You can send them the information on your boat and the smart guy will give a recommendatio. ------------- Bill http://www.freewebs.com/billsboatworks - http://www.freewebs.com/billsboatworks www.freewebs.com/billsboatworks 1987 SN Rebuild Project |
Posted By: 81nautique
Date Posted: February-03-2007 at 10:12pm
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You could speculate all day long but I would put the original prop back on and see what you get. Take you rpm and top speed numbers and then call a prop guy and they can help you select the right prop or make mods to your existing one.
I think if you try to figure out what's going to happen before you sea trial the boat you will be doing something twice. ------------- You can’t change the wind but you can adjust your sails |
Posted By: redneck7
Date Posted: February-04-2007 at 3:20am
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81nautique, I hear ya...I'm just curious...hate waiting, ya know? I reckon y'all are right, just take what I have (preferably AFTER the initial sea-trial) and head to a prop shop. Pretty much the conclusion I came to just thinking about it.
Gracias, Ryan ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=1620&sort=&pagenum=1&yrstart=1981&yrend=1985 - My 1983 Fish Nautique |
Posted By: 81nautique
Date Posted: February-04-2007 at 8:21am
redneck, patience is not one of my virtues. I'm in a similar repower situation and called Amce about what we should do to my prop and he told me to sit tight until we run it with the old one and go from there. Patience is over-rated.
 ------------- You can’t change the wind but you can adjust your sails |
Posted By: reidp
Date Posted: February-04-2007 at 2:29pm
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'7, What they said, in regards to trying the original first. More pitch won't typically be needed since your displacement isn't going up. Chances are you're picking up 70HP but a minimal increase in usable torque, so to feel this additional power it's going to come with the extra 500+ rpm this engine should turn. IMO and from past experience. i.e., the fuel injected higher HP Correct Craft Nautique engines don't come with a higher pitched prop than the carbed engines, did they guys? ------------- ReidP /diaries/details.asp?ID=231&yrstart=1971&yrend=1975 - 1973 Mustang |
Posted By: TRBenj
Date Posted: February-04-2007 at 4:49pm
Nope, they didnt. Props designed for the new boats with 330 hp work well on the older ones with 240hp. ------------- |
reidp wrote:Posted By: redneck7
Date Posted: February-04-2007 at 11:19pm
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Cool...so the prop may be OK?
Adding 90hp didn't actually add much usable torque? I understand that it may have not added torque throughout the powerband depending on where it makes peak hp, but Torque = H.P. x 5252/RPM...that much I learned in 3 years of Mechanical Engineering, so I got some more torque somewhere... What about a new cam or some bolt-on power adders...anything like that that's worth a darn to do on a boat? If so, I'd like to do it before I put any time/money into potentially repropping. ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=1620&sort=&pagenum=1&yrstart=1981&yrend=1985 - My 1983 Fish Nautique |
Posted By: reidp
Date Posted: February-05-2007 at 9:32am
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'7, you definitely have more torque, but it's more a function of at what rpm in terms of what prop you need to turn. If your new engine was a 320 HP diesel, you'd be turning something much larger diameter and/or pitch wise, as a result of the incredible low-end torque. Or even a 300 HP 454 would require more prop. If you built a 320 HP 302 on the other hand, you may have to turn a smaller prop in order to let the engine reach its power band. Anyway, your target should be to reach somewhere around 5000 rpm WOT, or whatever the mfr recommends, but it is definitely a higher rpm than the 45-4600 the original 351 was scheduled to turn, and that 500+/- rpm is your extra 70HP. Bear with me if this is info you're already familiar with.
As far as upgrades go on a new warranted engine, I might limit them to external bolt-ons like an intake. And unfortunately, the bigger and heavier the boat, the less significant the results will be in terms of speed and economy. Good luck with it anyway and have fun and let us know how she runs. ------------- ReidP /diaries/details.asp?ID=231&yrstart=1971&yrend=1975 - 1973 Mustang |
Posted By: redneck7
Date Posted: February-05-2007 at 11:09am
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Thanks for the info...I reckon I should have known all of what you just said because it makes sense, but I just wasn't thinking about it like that..
Should be doing initial shakedown/sea trial, etc in the first week of March, so I'll update then. Thanks again ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=1620&sort=&pagenum=1&yrstart=1981&yrend=1985 - My 1983 Fish Nautique |
Posted By: Hollywood
Date Posted: February-05-2007 at 11:20am
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redneck, your link says 1982 and your Diary page says 1983. ------------- |
Posted By: fishyflorida
Date Posted: February-05-2007 at 11:41am
| Quick thought - Since the original was a factory 351, spinning reverse of a car engine, did you install a reverse 350? Most new 350's are standard rotation, so using the old prop might not be an option... |
Posted By: reidp
Date Posted: February-05-2007 at 12:30pm
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...but it'll go like hell in reverse. ------------- ReidP /diaries/details.asp?ID=231&yrstart=1971&yrend=1975 - 1973 Mustang |
Posted By: redneck7
Date Posted: February-05-2007 at 1:56pm
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I'm praying the mechanic who did it (I didn't do any of the work aside from screwing up the 351) got a proper rotation engine.
Hollywood, I know...just changed the diary last night...there were a lot of discrepancies in the paperwork with my boat and we just found out definitively that it is an 83. It was advertised as an 83 (correctly), titled in Florida where I bought it as an 82 yet with the correct HIN, and the Florida registration listed it as an 84. Sounds fishy, but after spending time with the owner, I'm pretty sure he was just a little dense combined with the fact that he owned the boat 50/50 with his brother in another state, so all of the paperwork was done long distance. So I guess this is a short version: I didn't know the year, but I'm pretty sure now it's an 83. ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=1620&sort=&pagenum=1&yrstart=1981&yrend=1985 - My 1983 Fish Nautique |
Posted By: redneck7
Date Posted: February-06-2007 at 1:58pm
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Anyone know what the stock wheel specs are? ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=1620&sort=&pagenum=1&yrstart=1981&yrend=1985 - My 1983 Fish Nautique |
Posted By: john33617
Date Posted: February-09-2007 at 8:32am
| 14x11 , and I would stay with that , do not over prop , I think you can clock the trans for rotation , but better ask the trans guy here. |
Posted By: redneck7
Date Posted: March-07-2007 at 2:23pm
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Ok, I just took her out for the first time with the new engine and had to pull the throttle back when she spun right up to 5000rpm and was only hitting 32mph.
Thoughts on where to go from here? ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=1620&sort=&pagenum=1&yrstart=1981&yrend=1985 - My 1983 Fish Nautique |
Posted By: 79nautique
Date Posted: March-07-2007 at 6:54pm
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what prop do you have and what was the max rpm 5K? is it a balanced motor? i/o's run 5k all the time and you hav a merc engine right? ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=756&sort=&pagenum=1&yrstart=1979&yrend=1979 - 79 nautique |
Posted By: bkhallpass
Date Posted: March-07-2007 at 6:59pm
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Isn't the real question, which prop helps you catch the most fish? BKH ------------- Livin' the Dream |
Posted By: michigan dave
Date Posted: March-07-2007 at 7:06pm
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I believe your underproped at this point. The recomended rpms of most of the sbc engines I have worked on hover somewhere around the 4500 point. Some a few higher some a few lower. The fact is your only runing 32mph. that boat should run in the mid to upper 30's with that motor and the right prop. Your not looking for a arm streching hole shot. Lets face it, its a fishing boat. If your like me you want longevity, reliability, smooth idle, good troll. ect. I have a four blade acme on mine
I will have to look and see what pitch. I love it. dave. ------------- 1984 Fish Nautique 351ci- 14x13 four blade acme south haven mi. |
Posted By: redneck7
Date Posted: March-07-2007 at 7:13pm
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Max RPMs are 4800. I'd rather have a slow holeshot and more speed on the top end (on a smooth day it could get me toward the gulf stream that much quicker).
What's the shaft size on these bad boys? ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=1620&sort=&pagenum=1&yrstart=1981&yrend=1985 - My 1983 Fish Nautique |
Posted By: michigan dave
Date Posted: March-07-2007 at 7:20pm
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I am running a 13x14 four blade Acme #504, I belive most if not all F.N have a 1 1/8 shaft.
I am slightly overproped with my fresh 351. I can smell 40 statute mph on a good day measured with a paddelwheel/fish graph.not GPS. dave. ------------- 1984 Fish Nautique 351ci- 14x13 four blade acme south haven mi. |
Posted By: redneck7
Date Posted: March-07-2007 at 9:53pm
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Thanks for the info Dave. I'm hoping to chat with a prop shop or two tomorrow and I'll let you know what they say just for the posterity of the few of us who have Fish Nautiques. ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=1620&sort=&pagenum=1&yrstart=1981&yrend=1985 - My 1983 Fish Nautique |
Posted By: redneck7
Date Posted: March-12-2007 at 11:24pm
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Engine= 2007 Indmar Vortec 350.
Prop= 13.30in diameter, 12in pitch and tons of cup. Performance @ WTFO= 40mph and 4600RPM. There it is in case someone uses the search function down the road. ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=1620&sort=&pagenum=1&yrstart=1981&yrend=1985 - My 1983 Fish Nautique |