Am I under-propped.. ??

[Kitimat]

I recently purchased a 26.5ft sangster cruiser with command bridge, it has a 351 I/O.I cant get it to plane, at 3200rpm it moves at 16mph. It presently has a 15 Pitch prop, I do have trim tabs but they dont make any difference at present. Do I need more pitch, any ideas welcome....THX

 

[roscoe]

Re: Am I under-propped.. ??

Just the opposite in my opinion.<br />Less pitch, will allow engine to run at higher rpm, and provide more power to the prop.<br /><br />So you are running wide open, at 3200 rpm, plowing thru the water at 16 mph? It sounds like something more may be wrong.<br /><br />By the way, you posted this question in the fishing forum.<br /><br />You should use the drop down menu near the bottom of the page, select the "boat questions" forum, press "GO".<br />The post your topic/question on the boat page. You will get more responses there, as more members will see your question.<br /><br />Good Luck.

 

[JB]

Re: Am I under-propped.. ??

Moving to Boats.

 

[flashback]

Re: Am I under-propped.. ??

I agree with roscoe's second comment, "It sounds like something more may be wrong." Has the boat always run like this since you have had it? My guess, (and only a guess at this point), is that I would first start by doing a general tune-up on the engine. It should be turning in the mid 4s at WOT. the 15" pitch is probably about right for a boat that size with that engine...

 

[beckerdg]

Re: Am I under-propped.. ??

Is the hull clean?

 

[airman]

Re: Am I under-propped.. ??

Make sure the hull doesn't have any water trapped in the floatation compartments. Unfortunately, if you don't know how high the boat is supposed to sit in the water the only way I know how to check is to drill a small hole and see what comes out. I would assume the prop is right and look elsewhere first.

 

[Solittle]

Re: Am I under-propped.. ??

Kit - I think you are on the right path. I had a 27 1/2' flybridge with a volvo/350 cu in that would not plane. I went to a prop shop and explained what I had & how it performed. He sold me a prop that got it to plane. I don't remember the details (14 yrs ago). The 350/351s just don't have enough power to move a boat that heavy. Mine was working its guts out. Really need a 454 or just accept that you will be goin sorta slow.

 

[magster65]

Re: Am I under-propped.. ??

Hey Kitimat. That's a heavy boat for a small block. I have a 26' Comand Bridge x 10' beam (Tolly) with a 7.4 Merc. / velvet drive / straight shaft. It weighs in at 9000 lbs.+, planes at 2300 rpm @ 12 mph and revs out to 4400 @ 26 mph on gps (a little faster after fresh bottom paint). Like the others have said, assuming your engine's strong... I would check to make sure your leg goes all the way down and try and move some weight forward. From there I'd freshen up the bottom if there's any sign of growth. You may have the right prop. Good luck.

 

[wilkin250r]

Re: Am I under-propped.. ??

Is the trailer still hooked to the boat?