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Old 07-03-2014, 11:12 AM   #88
RichF
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City: Long Beach
Vessel Name: Tivua
Vessel Model: 36' Island Gypsy Europa
Join Date: Apr 2014
Posts: 38
Quote:
Originally Posted by manyboats View Post
RichF wrote;
"Eric, what kind of speed are you getting? Not that your hull will at all compare to my hull speed, just curious. I do think my prop guy was wrong and I intend on confronting him on the issue."

I get a max around 7 knots and cruise at 6.15. But I have only 40hp and a full disp heavy 30' hull. I do max out at 3000rpm at WOT. Run 2300 at cruise.

I think your problems would be over if you adjust your engine load to allow your Lehman to max at 2500rpm. Did you ever firm up the gear ratio? If you've got 2-1 you need 3 blade props IMO.
OK I read back and see you have confirmed the 2-1 gear ratio. Think 3 blade props. If you get real lucky you could find them used but ....

I went back all the way to your #1 post. It seems you have tried the 23" three blade prop and only got 2000rpm. Is that correct? And I gather you're a single engine boat. If that's so I'm not sure what to say and I'm not often speechless.
Yes, single engine and yes I did also try a 3-blade although it was a large 3 blade). I just talked to my prop guy and he is standing by his choice on the new prop size he gave me. (23x15-14; 4-blade) I told him to humor me and say he is wrong, what size would I need to get to 2,500 rpm if the one he made for me was only getting me 2,000 rpm. He said look for a 3 blade 22" x 14", 15" or 16" pitch. I just talked to the guys a Vic Prop too and here are their calcs. What do you know, calling for a 22"x15"-16" THREE blade, smaller size and pitch if I want a 4 blade but that's a pretty much impossible prop to find. So now I go prop hunting....

Could have bought a nice new electronics package with what I have wasted on money here....

I'll post back later with results (no doubt I am NOT the only guy out there having this issue). I sure hope this info. will help some other poor soul...
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