Water, water everywhere

[Roverdog]

I have a 20 foot V-hull open boat with two 40 hp johnsons to run it. When underway each motor is causing a large stream of water to come up between the two motors. The stream , if I open up the motors, completely covers the cover and most of the rear part of the outboard. I am nervous that water will enter each motor, leaving me stranded. Is this ok, or should I look for a solution. Some people say that the boat is made for only one motor in the center of transom. Any ideas??

 

[tcgobucks]

Re: Water, water everywhere

without knowing the boat, the easiest thing I'd suggest is to try moving the motors up or down 1 notch with the tilt pin. See what happens, if it gets rid of the water and doesn't effect your ride, then you're all set. Good luck

 

[Chris1956]

Re: Water, water everywhere

Have someone drive the boat, while you look at the motors. See if you can figure out where the spray comes from. Go slow at first so you can see it start up.

if the motors are set high on the transom, with the antiventilation plate above the water, spray can come off the gearcase, and not get knocked down by the antiventilation plate.

 

[Home Cookin']

Re: Water, water everywhere

regardless of cause you should fix it; motors are waterproof but not water tight. Keep them dry. Especially in salt water.

Consider mounting a deflector on the transom if you can clear the motors.

Twin 40's is an odd rig; I think it may have been seen more 50 years ago. There's a reason why you don't see it any more. Sell the 40's and buy an 80, so to speak.

 

[shrew]

Re: Water, water everywhere

There are plenty of boats with twin OB's. I don't see why the size of the boat or motors would matter, provided they are sized correctly. There's no magic that prevents this on twin 150's and causes it on twin 40's.

 

[Bifflefan]

Re: Water, water everywhere

Is one a counter rotator? Maybe they are mounted on the wrong sides.
Some sort of splash plate should do the trick if the engines are mounted correctly.
Twin 40's on a 20' boat is not much power, that's less than half what I have on my 21', and mine is not power house.
I do like the twins tho, you almost always have a spare. And you have a wide range of maneuverability with them.

 

[mbgaski]

Re: Water, water everywhere

There are plenty of boats with twin OB's. I don't see why the size of the boat or motors would matter, provided they are sized correctly. There's no magic that prevents this on twin 150's and causes it on twin 40's.

Twins work fine, but are naturally going to introduce a more complex system which equates to more chances for things to go wrong. Twin 150's = 300hp, which is a bit high for an OB (do they even make them 300hp yet?). If you want big #'s like that then you need to go twin. Twin 40's though = 80hp which is easily attainable via a single outboard. Seems inefficient for a dual setup.

Even that said, I'm not familiar with the boat in question, but 80 hp seems awfully low to be pushing a 20ft anything. I've got a friend with a 19' Sea Ark CC that has a 115hp on it, and even that seems a bit underpowered when he goes WOT.

 

[Roverdog]

Re: Water, water everywhere

The reason for the twin 40's is that I usually fish for cod about 8 - 10 miles off the coast. Having a spare in ocean conditions is a must. The single 40 can drive the boat about 25 km/h full out. I usually only run one at a time, but the shape of the boat botton might have something to do with the water problem.

 

[Fireman431]

Re: Water, water everywhere

Are they counter-rotating engines? If so, the propellers should spin to the outsides of the boat. This will give you better handling on top of not having the enormous amount of water washing up between the two. If they are spinning towards the midline of the boat, switch sides.

 

[Chris1956]

Re: Water, water everywhere

Counter rotating motors are better than conventional rotating motors, but are not likely the cause of the issue. There are plenty of boats out there with twin screws that are not CR, and they work fine.

He needs to find out where the water is coming from.

 

[Snobike Mike]

Re: Water, water everywhere

(do they even make them 300hp yet?).

Yes they make 350's now.

If you want big #'s like that then you need to go twin. Twin 40's though = 80hp which is easily attainable via a single outboard. Seems inefficient for a dual setup.

Indeed. Twin 40's will probably perform like a single 50 or 60 not as a single 80.

My guess is motors are too low causing the side spray.

Good luck.

 

[Roverdog]

Re: Water, water everywhere

Thanks everyone for the advice. I think that a Johnson dealer here may have the answer. He said that the V-hull inclines from the keel to the outside . in order to keep the water down I need to keep the bottom of the hull on the same plane as the anti cavitation fin. Right now the fin is below the hull due to the incline of the v-hull. Simply tilting the motor up a notch does not work, just raises the bow some more. Thanks all. Any more opinions or advice is still welcome. He may be wrong!

 

[GrindKore]

Re: Water, water everywhere

Thanks everyone for the advice. I think that a Johnson dealer here may have the answer. He said that the V-hull inclines from the keel to the outside . in order to keep the water down I need to keep the bottom of the hull on the same plane as the anti cavitation fin. Right now the fin is below the hull due to the incline of the v-hull. Simply tilting the motor up a notch does not work, just raises the bow some more. Thanks all. Any more opinions or advice is still welcome. He may be wrong!

Here are some suggestions;
1) Make sure both motors are evenly trimmed .
2) Try adjusting trim up or down.
3) If you have hydrofoils, take them off if you can.