The best fuel economy - outboard on V

[pjbrownva]

Originally Posted by bgreene

Let us know after you change prop ..... thinking your top speed should go up too

Added a doel-fin on Sunday, and much to my surprise WOW!

I gained 6 MPH on the top end, the engine now hits 35 MPH at WOT with the motor at close to full-down and with the trim tabs all the way up, and she now hits 6200 RPM with that setup (as opposed to about 5400 without the fin).


I get more stern lift, so she rides better and faster with the trim tabs all the way up.

Best speed I got was 35 MPH (GPS)... (50 Gallons of gas... and just me on the boat) with the motor close to full down and no trim tabs... and she now she sings at about 6200 RPM like that. As I trim the motor higher, RPMs increase, but not necessarily speed (I think I get more slip)... when I'm at or near maximum motor trim up, I can hear the prop slipping more and I can the rev limiter.

I'm happy with this 14 x 17 pitch 3 blade suzuki SS prop, and plan to keep it now that I added the doel fin.

The bottom of my boat is rough.... there are some painted over barnacles on the bottom, that I've been slowly scraping off. Because I trailer exclusively, my ultimate plan is to sand and scrape the bottom and refinish with either a gel-coat layer, or a good, smooth long lasting finish (NOT anti-fouling paint,.. since I trailer exclusively).

I expect once I get a smooth bottom and way 'er up, that I'll see even better performance. :-)