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Stern Too Low In Water

J

jmerritt

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I have a 1998 19' Godfrey Hurricane Deck Boat that I have restored. The problem is that the stern rides about 18 inches too low which floods the transom. Engine is the original 1985 Johnson 150 OB which is what is rated as the maximum for this boat. I have not changed anything weight wise from the original design but I did remove some bad foam that was located in the stern. My question is will adding closed cell foam back into the stern raise it. I have read a number of posts about foam used for buoyancy in the event of taking on water but can't find specifics to my issue. Thx John
 
To me closed cell foam is Styrofoam, the white stuff coffee cups are made of. Other than feathers probably the lightest stuff you can buy. I had it in sheets in the bottom of a '65 Starcraft 18' Holiday I/O. On other types of foam, like 2 part sprayed in which to me is not closed cell, the majority of it is air so there isn't much dead weight there either. You could probably take a couple of gallons of it weighing maybe 10# per gallon, and when properly installed float your whole boat.

The problem is that you are talking about water displacement. Buoyancy of a floating object is nothing more than displacing an amount of water equal to the weight of the object.

Take a container and fill it completely full of water. Place the item of unknown weight into the water. Measure the weight of the water that overflowed the container. That is the weight of the object.

If the weight of the object and it's buoyancy are equal it will fully submerge but not sink. If heavier it will, and if lighter it will have areas above the water line, like boats have. Putting foam inside your boat where it is not in contact with the water will just add dead weight to the boat and make it sink farther in the water.....but not much for that, if measurable. To be doing you any good it has to be physically displacing water....like if your boat is submerged and the interior is full of water, if you have enough foam to displace water that is equal to the weight of the boat it won't sink, but will be fully submerged. As said, if an insufficient amount it will and if more than necessary part of the boat will be out of the water.

Is there any water in the stern of the boat, in the bilge? 18" is a lot of unbalance. Seems like you are talking about several hundred pounds came from nowhere. You said you changed nothing but removed some foam. Doesn't make sense man. What was the attitude of the boat before the restoration? Did it sit low in the water then? If so, then you may have some other parts water logged.

Water weighs 7-8# per gallon, forget exactly. Your 150 engine weighs like 400# and it doesn't make your boat squat right. Additionally it is at the very stern of the boat which would make more imbalance than you would have if it were mounted mid ship.

So, even if you had the weight of the OB, 400# of water inside your boat, you are talking about a 55 gallon can (drum equivilent) of water somewhere at the stern of your boat. That ought to be obvious.

Does the boat have a double hull? Years ago, boat builders would put in the floor (deck) and then seal it as an air chamber. They didn't use foam. This trapped air was your flotation. As boats aged, the glass seals, like from the deck to the sides (sides flexed and broke the seals) would crack and allow water to enter this air compartment. I had one and every two or three outings I would have to drain the water out of this "air" tank, a lot of water.

What model do you have and is it anything like currently advertised models on their www? Is it an all FG hull conventional deck boat, or a toon? What did you change when you restored it other than removing the foam?

Just brainstorming here to help you. Not there so I can't do more than this.

Mark
 
Thx to everyone for your replies, It is a 1998 196 FishnFun and from what I see on the Godfrey website is pretty much the same as the new ones except for the modernized seats, controls, etc. It is all fiberglass and in looking at it I am not an expert but I don't think it is a double hull. It takes on water because the transom sits too low and water eventually enters the steering cable and engine control openings. I know I can seal those but I am trying to see what I can do about raising the stern. I will look to see about moving weight to the bow. It sits low in the water at the stern as soon as I put it into the water. Engine is original.
 
jmerritt said:
Thx to everyone for your replies, It is a 1998 196 FishnFun and from what I see on the Godfrey website is pretty much the same as the new ones except for the modernized seats, controls, etc. It is all fiberglass and in looking at it I am not an expert but I don't think it is a double hull. It takes on water because the transom sits too low and water eventually enters the steering cable and engine control openings. I know I can seal those but I am trying to see what I can do about raising the stern. I will look to see about moving weight to the bow. It sits low in the water at the stern as soon as I put it into the water. Engine is original.
Click to expand...

Not being there and seeing, I'm going to "betcha" water has made it's way into the bilge over the years your having noticed the route, and you have a water absorption problem in addition to a volume of unwanted water on board. Makes sense as water seeks a level and if the transom is low, which they normally are with all the stuff back there, the water will migrate back there and aggravate the problem. Opinion: Until you get the water logged stuff out, water removed, seal off the area where it is and stop the intrusion you are not going to solve your problem. Everything you come up with is just "painting over the rust". You don't think for a minute that your boat sold new sitting in the water at that attitude? I'd certainly doubt it.

HTH,
Mark
 
The other possibility (and more likely) here is that your transom has become waterlogged, thereby adding considerable additional weight to your stern and throwing the boat off balance. If it is waterlogged, it is also probably rotten, which means a complete transom rebuild. You need to haul the boat and test it. Measure the thickness of the transom at the drain hole. Just above or beside the drain hole drill a 1/4 inch hole about 2/3 through the transom thickness. See if any moisture weeps out. If so, it's soaked, and trash. Dig around inside that hole with an ice pick to check the state of the wood. If bits of soggy or flaked wood are pulled out, it's rotten. Drill a few additional test holes out near the chines and just under the engine mounting bolts and test the same way. If everything is dry and solid, then re-fill the holes with a good marine epoxy, or 3M 5200.
 
Some folks drill a few small holes in the transom from the inside to check decay starting near the bottom....say 3-4" from the bottom. Use something like a 1/8" bit with a variable speed drill. As soon as you get through the FG outer lining and into the wood, slow down to a creep. Check the filings. If not absolutely dry you have water absorption. Reseal hole if dry with RTV. Usually when the transom is compromised, you can run the engine and watch it when accelerating. If you see any flexure at the engine mounts, you have a problem.

On the 18" of depth change and that as a problem, I think there is more to it. 18" is a heck of a lot of excess ballast.

Mark
 
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