72 Crestliner 16' v hull wake problems (spraying up)

[unior]

Just finished transferring my friends 60hp mercury from the old sinking 16' trihull to the new to us 1972 16' crestliner apollo 16 rts v-hull. The crestliner is wider and has taller sides than the old boat. The new boat has a cutout in the transom though and I measured the same distance from the top of the cutout to the bottom of the hull...

After switching from an 11 pitch 3 blade to a 10 pitch 4 blade the boat performs fairly well. I can get on plane about as quick as the old lighter boat even though we did lose a few mph of top end speed.

The problem is for some reason the wake is shooting up a stream/spray of water originating from the lower end of the powerhead/upper end of the lower unit. The water shoots up and outward spraying the engine cover with water. Some water is even penetrating the engine cover while on plane.

One thing to consider the power trim is currently dead and we have been running the engine trimmed fully down/in. Moving weight from the front to the rear of the boat gains me a couple mph but makes no difference with the walls of water being sprayed 5 feet into the air.

The power trim has been broken but the old trihull did not have this problem.

Engine is a 3cylinder 2 stroke 60hp mercury possibly a 1994.

Any help would be greatly appreciated.

TIA
unior

 

[Texasmark]

Re: 72 Crestliner 16' v hull wake problems (spraying up)

Get someone next to the engine that has a little mechanical moxy!!!! The anti-vent/anti-cavitation plate is just above the prop. Above that, about 2-3" is another plate the protudes forward of the mid section. It's purpose is to deflect the water you are talking about.

If it is below the level of the water coming off your transom, your engine is too low and that is causing your problem.

Mark

 

[unior]

Re: 72 Crestliner 16' v hull wake problems (spraying up)

Get someone next to the engine that has a little mechanical moxy!!!! The anti-vent/anti-cavitation plate is just above the prop. Above that, about 2-3" is another plate the protudes forward of the mid section. It's purpose is to deflect the water you are talking about.

If it is below the level of the water coming off your transom, your engine is too low and that is causing your problem.

Mark

Thanks for the rapid response. I admit I had to type "define: moxy" into google.

I actually did lean out over the transom to try and figure out the problem but came to no conclusions.

Whats the best way to determine the proper mounting height for my engine/hull configuration?

TIA
unior

 

[Texasmark]

Re: 72 Crestliner 16' v hull wake problems (spraying up)

Variables all over the place. General rule of thumb is to have the anti-vent plate...the one right above the prop even with or just above the water coming out from under the transom when at normal running trim and at the high end of the rpm curve (WOT area).

Anything higher and you can ventilate in rough water and turns, and lower is excessive drag and if really lower the problem you are experiencing.

HTH,

Mark

 

[Willyclay]

Re: 72 Crestliner 16' v hull wake problems (spraying up)

I do better with pictures so maybe the link below will help you. Pictures of your motor & transom exterior may help forum members with their recommendations. Good luck!

http://continuouswave.com/whaler/reference/engineMountingHeight.html

 

[unior]

Re: 72 Crestliner 16' v hull wake problems (spraying up)

Ok. I will put the boat in the water...put some weight in the back to simulate the on plane angle...then look at the anti cavitation plate depth.

I'll report back.

Thanks.

 

[ufm82]

Re: 72 Crestliner 16' v hull wake problems (spraying up)

No need for that. Run a yardstick, a board, a fishing rod, anything straight along the bottom of the keel at the bottom of the V and let it stick out past your engine. Measure where your anti-ventilation plate is in relation to the stick. It needs to be an inch or so ABOVE the stick. See the picture posted above. The plate should be above or on top of the water when you are running.

 

[ezmobee]

Re: 72 Crestliner 16' v hull wake problems (spraying up)

Motor might be mounted too low and you're definitely trimmed in too far. Might have to do something about that broken power trim.