1982 Supra Mariah leaks

[davebloom]

I am new to boating and have a 1992 boat that seems to have a consistent slow leak in the middle of the hull. Not quite sure where to look or how to look for it as the engine compartment is only so big. Any suggestions? Do I dry dock at and fix the fins?

[michael hunter]

Are you sure its not the prop shaft packing? They are supposed to leak a few drops per minute to lubricate the packing.

[cadunkle]

It could also be the rudder port, earlier models have a packing gland but a 1992 probably has o-rings. I had to remove and reseal my swim platform brackets a few years ago, at least one was leaking. There's only a few places water can leak in these boats. I also tighten all coolant hose clamps every spring when getting the boat ready. Never had one leak but I try to stay on top of preventative.

[davebloom]

Are you sure its not the prop shaft packing? They are supposed to leak a few drops per minute to lubricate the packing.

Nope it’s not that. I also found a couple leaks around the engine mounts and took care of those as well. It’s definitely coming from the front part of the boat and when I turn the bilge pump on when I first leave the dock it’ll run for a couple minutes with a solid strain

[davebloom]

Do these boats have fins / rudders in the bottom of them or some type of protruding pieces of steel that help with the turn on the boat? The other day I pumped out all the water and I took towels and dried out the whole area and then I sat and watched to see where the water was coming from. It’s coming from towards the metal or in front of the engine compartment area.

[cadunkle]

Tracking fins have through bolts into the bilge, one pair goes through part of the pylon mount. Never heard of them leaking, but it's possible they could need to be cleaned up and resealed. The garboard plug for the drain plug could also be leaking. If you have Perfect Pass there may be a through hull for the paddlewheel which could have a leaky o-ring or less likely need the through hull fitting resealed.

[Mischief IV]

Tracking fins have through bolts into the bilge, one pair goes through part of the pylon mount. Never heard of them leaking, but it's possible they could need to be cleaned up and resealed. The garboard plug for the drain plug could also be leaking. If you have Perfect Pass there may be a through hull for the paddlewheel which could have a leaky o-ring or less likely need the through hull fitting resealed.

Unless the skegs (fins) have been replaced due to prior damage, I agree with Cadunkle, no way that is the cause. Drain plug...perhaps. My older boats leaked at the shaft packing and the rudder.

[Salty87]

Where the water enters and where it appears could be 2 very different spots. Plus, in front of the engine is the lowest point of the bilge so a likely place for accumulation. Another common source of leaking is where the transom supertraps overlap the exhaust tubes about 2" up the pipes from the transom.

[davebloom]

Thanks for the information. There is a lot of water coming into this boat under the engine area. When it is docked, The front of the boat is tilted up. I’m not a true boater yet so I don’t know the terminology. I know that when I use towels to dry that area out, all the water came from the front of the boat. I sat and watched it come in. I just can’t see far enough up in front of the engine say where it’s coming from.

What is the transom?

Is the drain plug located directly under the engine?

The shaft packing is not leaking anymore. Should it be?

What is the pylon mount? And garboard plug?

Many thanks for asking these questions. This is the first boat I’ve ever owned in my life and I’m 55 years old. Trying to figure it out. Enjoying the challenge.

[Salty87]

Pics are always the best way to go. These boats aren't rocket science but there's a learning curve. Good for you buddy. Many of us started learning on old Supras. You've come to a good place. Some of these items have multiple names based on region or old school/new school.

transom- the stern section of the hull (the swim platform is mounted to it)
drain plug- there's one forward of the engine (also sometimes called garboard plug...old school) and another mounted on the transom that's not often used because it's really hard to reach but can still leak...some models may not even have the transom plug
shaft packing- you could have packing that should leak or or a seal that shouldn't (we can tell you if you pics)
pylon mount- refers to the ski pylon for attaching ski ropes that is located immediately in front of the engine

Again, just because water appears to be entering the bilge from the front doesn't mean it's entering from the boat from the forward parts of the hull. There are way fewer points forward of the engine where water can enter compared to aft of the engine. Take a look under the hull if you can and you'll see. Plus, when underway, the hull forward of the engine is mostly out of the water.

[davebloom]

OK thank you for the information. Very much appreciated. I would’ve never guessed those definitions.

I pulled the boat out yesterday and plan to let it dry out for a day or so. Friend of mine told me to take the garden hose and fill out the bottom of the boat and get underneath and look for leaks. Sounds like a good idea just not sure.

I know that most the water comes in to the boat when I first take it off shore and onto the main lake. There’s a canal I have to travel that’s approximately 100 yards long before I get to the main lake. By the time I get to the main lake the bilge pump is already turned on by itself and is pumping a steady stream. After that it’s just a constant on off of the pump was in is weird to me.

My concern is that the boat will take on water faster than the bilge pump at some point. So I’d like to find the source now.

I will post some pictures of my activities.

Many thanks for your help!!

[Salty87]

Filling the bilge sometimes doesn't work well. Instead of dripping straight to the ground water will run down the hull to the lowest point and drip from there. Plus, will take a good bit of water which you'll then have to drain.

Dry the inside of the bilge. Have your buddy drive at hull speed (as slow as possible) so you can open the dog house to take a look. It's most likely the driveshaft or rudder. Next likely possibilities are a loose engine hose or the exhaust. The exhaust leak is hard to see because water doesn't immediately enter the bilge. It goes under the floors and finds a way into the bilge. And, the spot I mentioned earlier about 2" up the exhaust pipes needs to be sealed. If it's not leaking now it will eventually. It's a common source of rotten stringers/floors. Drain plugs can leak but rudders and driveshafts are more common. Rubrails can leak but again not as common.

Eliminate the obvious and work methodically.