Water pouring in over transom

[UNCC Grad]

I have a 1648 CC Alweld aluminum tunnel hull boat with a 40 hp Mariner. The boat also has floatation pods welded on the back of the transom to aid in shallow water operation. <br /><br />Recently I have had troubles with water pouring in over the transom during operation requiring me to run the bilges constantly. My gas tank(s) and batteries are located up front along with a bow mount trolling motor.<br /><br />This is driving me crazy b/c sometimes it will do it for a while and then for no apparent reason, the boat will seem to get up on top of the water a little higher and the problem will subside. When the water is coming over the transom, I get about 23-25mph and when it is running correctly, I get 27-29 mph.<br /><br />Until the past month or two, I haven't had this problem. It has come from thin air. For what its worth, the anti-cavitation plate is located about 1" above the bottom of the boat, 2" below the top of the tunnel. I can't raise the motor up anymore b/c the clamp will not hold onto the transom if raised. I even tried installing a doel-fin with no change.<br /><br />I am running a 10 5/8" 13P 3 Blade, but I'm not sure of the RPMs as I have no tach on the boat. The prop isn't in the best shape either. <br /><br />Could it possibly be a prop problem or do I need to look into a jack plate to raise the motor up?

 

[steelespike]

Re: Water pouring in over transom

It appears some subtle change has occured.Maybe retaining water in the bilge somewhere.Maybe something is damaged or stuck in or on the lower unit or bottom of the boat.Have you tried the trim adjust.A tune up on the prop wouldnt hurt.<br /> If there is flotation under the floor maybe it is saturated.I think the jack plate would be a good investment if you cant find the problem.<br />Its obvious the trim/height is at a critical point and some fine tuning may help.

 

[UNCC Grad]

Re: Water pouring in over transom

steelspike, I can rule out the bilge as it is a jon type boat and I have two 500 gph bilges in there to pump out the excess water that gathers from overflowing the top of the transom.<br /><br />With the boat riding that low in the water, the only thing I can think of is the prop is out of wack and not able to get the boat up on plane efficiently.<br /><br />I thought I would love having a tunnel setup for duck hunting and fishing the shallows, but now it seems like more trouble than it's worth. No one seems to know much about setting them up.

 

[steelespike]

Re: Water pouring in over transom

There is a lot of turbulance in the tunnel this <br />Im sure can cause all kinds of problems.The jack plate would set the motor back a little more, might be more stable water.And of course you would be able to fine tune the height.<br /> Maybe there is too much weight in the bow putting too much boat in the water.This would cause more turbulance and drag.Put the weight back toward the stern a little at a time see if you can hit a spot just right. It may sound screwy but try moving the motor right or left on the transom.It may only take a fraction.