Bigger Trim Tabs! - Maxum Boat Owners Club

DANWHOLIKESTOFISH · 12-15-2017, 03:34 PM

Howdy, '92 2300 SCR, 5.7, Alpha I, 3 blade 14 pitch aluminum prop, usually loaded with 5 adults (my three kids got a lot bigger in the last year!), a dog and a cooler... boating at 3600' elevation (Lake Powell).

I installed a new swim platform in June of '17, a very nice addition indeed! After the install she struggled to plane and didn't want to stay on plane. My mechanic said to try bigger tabs, so I found a set of 9x18 (the old ones are 9X12) on ebay for $55. I used the existing rams and had them on within two hours. What a difference! She pops right out now and I picked up some rpms and speed! I am going to put the 15 pitch she came with back on next trip and see what happens, she is winterized right now. As a disclaimer, I will mention the air temperature last trip was about 40 degrees cooler which probably gave me a little more peak power...

shrew · 12-15-2017, 04:32 PM

Are you sure 14" and 15" is the Pitch and not the Diameter? When I run through a prop calculator, I come up with options for 14" and 15" diameter and either 17" - 18" of pitch.

14" of pitch would be very low.

Diameter usually stays the same and pitch is what is tuned. There is only so much space to swing a blade between the prop shaft and the anti-ventilation plate.

DANWHOLIKESTOFISH · 12-15-2017, 05:20 PM

The props are 16" diameter, I am hitting target RPM at 3600' elevation, we are loaded heavy, I've not had her on any other lakes at different elevation. The prop ears look like Mickey Mouse ears... I figure to get close to 40 mph with the 15 pitch.

mmwjr · 12-15-2017, 07:03 PM

I didn’t know the Alpha could take a 16 inch diameter prop.

donald · 12-16-2017, 03:52 PM

The firs number on the prop is the diameter and the second number is the pitch (14.5X16) as an example!
I am with Mike as I have the same drive and I don't think a 16 diameter prop will fit!
Don

mmwjr · 12-16-2017, 05:02 PM

Did a little reading and it seems a 16 inch will fit but is used on houseboat applications. Just doesn’t sound right for the OPs boat nor have I heard of someone using this diameter before.

Phillbo · 12-17-2017, 01:00 AM

Lake Powell = The Best Lake EVER!!!!

We are heading up for 3 days tomorrow.

DANWHOLIKESTOFISH · 12-17-2017, 01:15 AM

I’ll put a tape on it when I get home. Some of y’all are taking this a little too personal... My boat has been serviced by the same shop since 1993. I thought this was about trim tabs! How many of y’all “experts” are dealing with altitude? Anywho, Merry Christmas!