Transom splash

[Paul B]

Whilst my wee Honwave 3.2ie is a great boat, it has one very annoying habit, or problem, it kicks a lot of water back over the transom at speed, which creates quite a wet boat, not sure what's causing it, Doesn't seem to make any difference if I sit on the tubes or in the middle of the boat, when out on the water, it has the Honwave wheels fitted and the engine is a Suzuki df9.9 converted to a 15hp and it's running a solas st/steel prop,standard pitch for the engine,

So any ideas of what's causing it or a remedy to stop it

[Paul]

Paul
The more I read about this problem the more I'm convinced there is not a 'common' answer IMO dependant on the boat or OB being used
For example the Bombard Areotec is notorious for this issue however owners having different OB's have had to raise, lower, fit doe-fins, cut down transoms, raise transoms, set different trim settings and the list goes on and on
Another example I can state from personal experience......Prowave 380 air-deck with 20hp Tohatsu, great performing sib overall but developed a 'hook' in the floor above 20+knots but as the set-up topped out around 22knots it wasn't an issue to me. Sold the boat on and the purchaser used a 10hp Mariner/Mercury and experienced this 'hook' at about half the speed and plenty of 'slash'

I'm no expert but looking at different OB's and their leg lengths vary from 15" to 17" yet all classed as a short shaft. Next look at the anti-ventilation plate/anti-cavitation plate on each OB and they are set in different positions front to rear, wider, shorter, different heights, leg face very sharp or some blunt
As an example here's a Tohatsu leg

Tohatsu leg

and here's a Honda leg

Honda leg

If I remember correctly the earlier Suzuki OB such as yours has a shorter cav plate to the latest ones which are supposedly reporting no 'splash'
Any chance of a photo of yours

I've no problems with splash at all......however bolt on a transducer for the fish-finder and it's awful .......that's how critical the exit of water from the transom is on boats

9-R on another thread is looking into this after 'mods' so have a read but not the same issue

[Paul B]

Couple of pics

[Paul B]

I think I can answer your problem easy Paul.
I've studied the videos in slow mo of our latest outing. When you get on the plane, the aft sits very low in the water, the water splashes up from the trim tabs and hits the launch wheel legs, that water then bounces off upwards and hits your launch wheels, which then diverts it over your transom and into the boat.
I think your launch wheels are attacked too low also
Take a pic of the transom wheels mount pls buddy so I can compare

Also, iirc .. Your dad removed the drain one way valve, if your plug isn't seated correctly or pops out, when coming of throttle to coasting, your own wake catching up probably pushes in too.
I would remove the launch wheels, reinsert the bung valve and try it again.

Your outboard is the same year (pretty much) as mine, the cavitation plate is the same on both.
I don't have those issues, my boat is very dry.

[Paul B]

Here you go Martin

[Martin]

Cheers Paul.
Those fittings are sited the same as mine, so at least you know it's not those.
I suspect a run out without the launch wheels will prove one way or the other. I still think the boat sits very low though. It's a shame we did t throw my outboard on with the stingray fitted. The boat will then plane much flatter and reduce that water turbulence behind you
I wonder also, if your boat is maxed out speed wise - Weight, wind , tide
. And the fallout behind you is just huge water dispersion as the outboard is at WOT???
Sounds a bit far fetched but ya never know

[Si Crowe]

thsi may sound stupid but the rubbing streak that runs the centre line of the hull, it curls upwards where it terminates on the "planing pad". could that be funneling water upwards (or even the rounded trailing edge of the planing pad itself) slightly at speed so it hits the leg above the anti ventilation plate causing the splash back and spray which in turn hitting the transom wheel brackets and sponsons? just a thought.

[Paul B]

Thanks for your input guys, I think firstly I will try it without the wheels on, hopefully this will be the issue, However I cannot fail to notice that the anti cavitation plate on the Suzuki is quite a bit smaller looking compared to the Honda and tohatsu engines, so could it be the design of the engine,

Maybe on Martins engine he doesn't get this issue as he's got the stingrays fitted will be interesting to try your engine in September on my sib

[stigoftd]

Had similar on my loadstar - i adjusted the trim of the engine and it solved the problem - took a bit of playing with but all sorted now

[Martin]

Maybe on Martins engine he doesn't get this issue as he's got the stingrays fitted will be interesting to try your engine in September on my sib

No problem, help yourself.
I suffer no splash back on the 3.8 whatsoever even without the stingray though