What am I doing wrong?

[Tom97Sundancer]

I have a 97 Sundancer 24' 5.7L with 350 hours. I think that motor has approx. 220 horsepower. My problem is I have yet to get the boat over 30 knots(clocked off the gps). I tried a 14.25 x 17 stainless prop that only gave me 4400 rpms at WOT, exchanged that for a 14.25 x 15 ss prop which now gives me 4600 rpms at WOT. Either way I'm barley getting to 30 knots. I know the rpm range for that motor is between 4400-4600. But can anyone tell me what the max speed should be?? Someone told me they were able to get 41mph on a 15 x 17 ss prop. So what am I doing wrong?? Thanks for any advice you can give me.

 

[mattttt25]

Re: What am I doing wrong?

your speed sounds a little low, but not much to me. how much does that boat weigh, motor and fuel? how many people, gear, etc? sounds like a heavy boat with not much engine (most 22' in that class run with 260 horses).<br /><br />i'd make sure the hull is clean and read up on your engine in the i/o forum. good luck-

 

[LubeDude]

Re: What am I doing wrong?

Are you using the trim to get the 4,400 with the 17P?<br />---------------------<br />

 

[cuzner]

Re: What am I doing wrong?

Hey Tom,Ive got a 94 da.with 5l engine I,ve got the the stock 14.5 17p prop on I,ve got 38mph at 4500 rpm, I could give it more but don't want to over rev.You should easily getting up at least to this with a 17p prop,with more power than me. The only non mechanical problems I can think of ... are you retratcing your tabs after you plane? and are tweeking your trim to get the most rpm? My dancer cruises at 28 mph at around 3200 rpm . I've got an old prop in getting re-pitched and am going to try 19p .<br /><br /><br /> Jim

 

[Tom97Sundancer]

Re: What am I doing wrong?

Lubedude-I've been adjusting the trim once on plane. According to the qauge the trim is up to the 1/4 mark. I play with it both ways and the 1/4 mark seems(to me) optimal.<br /><br />Cuzner-the tabs are up, I really don't use them to plane, just to keep the boat level. For the most part they are always up.<br /><br />Thanks for the feedback guys, atleast now I know I'm not irrational for thinking my boat is slower than it should be. Any other thoughts??

 

[Solittle]

Re: What am I doing wrong?

Tough to compare speed from one boat to another. Weight, bottom condition, hull design, fuel load all come into play. I would be quite satisfied with 30 kts out of a 24' boat with 220 hp.