AB 10 VS porpoising

[Flyboycj84]

Just finished a tender build and am experiencing some not so fun porpoising.

-Ab 10vs, 10.5ft (max hp 25, max eng weight 179)
-Suzuki df25a (25hp, 159lbs, 10.25x11 3blade prop)
-Highfield eurostyle helm
-fuel in bow locker, 40lb battery in console.

Rigged out she weighs 475lbs wet, and all tests have been done with me alone.....at 260lbs.

I ran it w no doel fin and no tabs.....couldn’t even get on plane, severe bowrise.

Then I put smart tabs on w 20lb actuators.....able to plane but had porpoise at anything above 12kts.

Then I switched out actuators to 30lb, was able to cruise around 17kts......anything above that and she’d porpoise......not terrible but not great.

So then I raised the motor a hole, so the AC plate was about 1/2” above the bottom of the keel. Ran it w the same tabs and didn’t seem to help a ton.

So then I removed the actuators and raised the tabs out of the way, and put a doel fin on. That was not really any help at all.

So......I’m either thinking I need to raise another hole. Or switch to a 4 blade prop. I have a tach coming in the mail so I can more accurately provide info.....but that’s where I’m at. The boat cruises ok.....I’m just trying to maximize and dial in performance.

Advice welcome.

Thanks!

[Callum B]

Im no expert, but it sounds more like engine trim / weight distribution.....youve obviously tried trimming the engine more forwards / vertical??
Try moving the fuel aft,....maybe take a couple of 25 litre water containers, and move them around to see what difference that makes??.....

[jeffstevens763@g]

have you got a picture of your set up?

[Flyboycj84]

Trying to upload a pic but having trouble.

[Callum B]

This is one way of posting pics.

[brveagle]

something is not right based on the fact that you can not even get on plane without assistance. Does your motor have manual trim?

[Flyboycj84]

Originally Posted by brveagle

something is not right based on the fact that you can not even get on plane without assistance. Does your motor have manual trim?

Power tilt and trim. The boat is fairly a$$ heavy.

[Flyboycj84]

I used the steps above and it says my picture is the wrong format. It’s from my iPhone photos.

[jeffstevens763@g]

I have the Df 25 it's more than capable of planing your boat if it's set up correctly as soon as we can see your set up we will know where the problem is

[Flyboycj84]

Still getting invalid photo type on my iPhone photos. Which I thought were png files. I’ll try from my computer when I get home on Sunday.

Either way.....the initial setup is with the AV plate about 1/4” below the keel. I also raised it a hole to make it 1/2” above the keel. I can still drop it down 2 holes to make it 1” below the keel.

[Callum B]

Hmmm......i still think its to do with the weight distribution, and fore / aft rake of the outboard,.....but as jeff said, a few pics would help.
I take it that it always porpoises on the plane, irrespective of speed??

And as brveagle said, there must be a fundamental problem, if it doesn't skip up on the plane....prop??.... maybe dragging your transom.??.....

There are better guru's on here than me.....im more trial and error, than genius theory

[Flyboycj84]

Originally Posted by Callum B

I take it that it always porpoises on the plane, irrespective of speed??

See original post

[jeffstevens763@g]

With my Mercury 365 SIB 10 1/4 x 11 prop I would plane At 10 knots calm 22 knots WOT with more weight than you cav plate level with the keel trim 2 holes back from the transom even weight distribution throughout