Prop

[Bill Almond]

I have a 250 SD, 5.7 260 HP / 230 HP at Prop Chev Eng. With 5 or 6 people on board I can't get on plane. I have been told that the Alpa 1 out drive is under powered for my boat. I have been reading up on different props and the more I read the more confused I become. I was told I could use a 16/16 prop,any one ever have this situation

 

[DJ]

Re: Prop

Bill,<br /><br />When you say "250 SD" I assume you mean that is a 25 footer?<br /><br />The 350 can be challenged if the 25' is a big wide heavy boat. The Alpha drive does limit you somewhat in prop. diameter, compared to a Bravo.<br /><br />However, ask yourself these questions first.<br /><br />1. What is my top rpm. with an average to light load?<br /><br />2. What is my current prop? Dia. and pitch.<br /><br />3. Are all the people in the back when I'm trying to plane?<br /><br />4. Do I have trim tabs?<br /><br />5. What is the trim setting when I'm trying to plane?<br /><br />There is a big "elephant ear" prop. available for Alpha I's. I've only seen it as a 15" X 15".<br /><br />Let us know the answers to some of the above questions, particularly top rpm., and we'll try to help you out.

 

[Bill Almond]

Re: Prop

Answers to your questions<br />250 does mean 25' OAL is 28.6<br /><br />My top rpm's with an average to light load is 44000 which gets me about 28 to 30 MPH.<br /><br />Current prop is 15/15 aluminum 3 blade<br /><br />When people sit on the bench seat at the back of the boat the boat will not get on plane and rpm's are around 38000.<br /><br />Yes I have trim tabs and I put them all the way down<br /><br />Thanks for helping <br />Bill