Hull seepage

Hi

We have a 1985 Chien Hwa trawler. We just had the boat hauled out for a new bottom paint and now there is seepage in the bilge, but it seems to come from below as there are no water tails from anywhere else. The bilge used to always be compley dry before.

The material in the bilge seems to be deteriorating and pieces come loose. What material could this be? Where is the water coming in through the hull? What is the best way of fixing this? It's slowly seeping in at the location marked in the photo.

Any recommendations how to take care of this?

Thank you so much.
Anja

I think the first step is to remove that old bilge pump and switch base. Then give the area a good cleaning so you can get a better idea of where the water is coming from. It’s possible that the bilge pump screws are too long and the sealant on them has failed.

Find a FG laminator.
They will grind that out and lay over.

As said above, the first step is to clean it thoroughly. Then see what it looks like. There may be a glass cover over the hollow keel. The keel may be filled with ballast like concrete. Is it coming out the outside of the boat or up through the bottom of the bilge?

HopCar said:

I think the first step is to remove that old bilge pump and switch base. Then give the area a good cleaning so you can get a better idea of where the water is coming from. It’s possible that the bilge pump screws are too long and the sealant on them has failed.

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A good possibility and I wonder if a sling or blocking were directly under that spot, i.e. a pressure/flex point, causing what you describe.

Comodave said:

As said above, the first step is to clean it thoroughly. Then see what it looks like. There may be a glass cover over the hollow keel. The keel may be filled with ballast like concrete. Is it coming out the outside of the boat or up through the bottom of the bilge?

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As far as we can tell, its coming from the bottom of the bilge. It does seem like the pieces that are loose are some type of concrete material.

Is the boat back in the water or still on the hard?

Usually the hollow keels are filled with something like concrete with some steel mixed in. If the water is coming up from inside the concrete it may be difficult to get out. If you are in an area that freezes it can freeze and expand and crack the hull. Probably the easiest way to get the water out would be to add a drain plug low in the keel. I would drill a small test hole and see if you get any water out. If it does then enlarge the hole to accommodate a drain plug. Let it drain and then put the drain plug in. If it doesn’t have water coming out then fill the small test hole. As to the top of the keel where it is fiberglassed, first get it really clean and see what condition the glass is in. If it is in poor condition then you could lay in a couple of layers of glass on top to seal up the ballast in the keel.

Soo-Valley said:

Is the boat back in the water or still on the hard?

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Back in the water.

soin2la said:

A good possibility and I wonder if a sling or blocking were directly under that spot, i.e. a pressure/flex point, causing what you describe.

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AnnaW said:

Back in the water.

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Then too late to look where it was blocked or the sling attached to see if this leak location was caused by that stressor.

As others have said remove the bilge pump base assembly, clean it up, dry it and monitor. If not too bad of leak, dry and add some glass over area until next haul out to check keel in that area.

I agree with those who suggest cleaning it thoroughly and monitoring.

If it were me, I'd get the diver to inspect for any damage, as a precaution. But, that isn't actually my first guess.

My first guess is that, while hauled, the boat sat at a different angle than normal and water drained into different places and you are now seeing it slowly move around and settle there.

I'd shop vac it up every few days and see if, after a couple of weeks, it was still happening. My bet is that it goes away.

If it doesn't go away, I think you really need to think about penetratiobs into the keel or where they could leak down into that space without being noticed. Things like zinc plate studs come to mind.

I respectfully disagree with the advice to glass anything, quite yet. I just don't see glass on the inside preventing water from getting in from the outside.But, I do see glass being hard to adhere to a wet surface and getting in the way of monitoring by hiding the problem area.

The hull is pretty thick that low, so it would be hard to imagine a
Problem from.bilge pump screws. But, maybe a leaky bilge pump hose, etc

Happy hunting!

-Greg

Some folks paint the bilge to make it look pretty.

Sadly the paint does not allow delamination,, grounding stress cracks or other damage to be observed.

I'd bet one of the Groco thru hull valves dried, shrunk a little while on the hard and you have a periodic slight trickle coming from one and collecting in the bilge. I've chased phantom trickles in my GB36.

Lay some toilet paper across the bilge fore and aft of the sump, as well as forward and aft in the cabin access floor boards. That will help indicate where water is flowing from..

If you determine it is a Groco, just check, tighten the access bolts.

It might be worthwhile to make sure the water is seawater. I wouldn't use the taste method though in case it is blackwater.

Comodave said:

Usually the hollow keels are filled with something like concrete with some steel mixed in. If the water is coming up from inside the concrete it may be difficult to get out. If you are in an area that freezes it can freeze and expand and crack the hull. Probably the easiest way to get the water out would be to add a drain plug low in the keel. I would drill a small test hole and see if you get any water out. If it does then enlarge the hole to accommodate a drain plug. Let it drain and then put the drain plug in. If it doesn’t have water coming out then fill the small test hole. As to the top of the keel where it is fiberglassed, first get it really clean and see what condition the glass is in. If it is in poor condition then you could lay in a couple of layers of glass on top to seal up the ballast in the keel.

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Perhaps we are witnessing why the Navy does not use fiberglass in its boats.

Water cycled over freeze and thaw while trapped in materials is extremely destructive. For this reason alone, IMHO fiberglass boats should never spends winters in the hard in areas with freezing temperatures.

If it were my boat what would I do? Learn to live with it and try to enjoy the boat. It is not going to get better and it may not be something that it is repairable.

an accumulation of shaft seal water or maybe A/C condensate?

I agree, time to wash and clean that area of the bilge. The wet/dry vacuum is a 'gift' to all boaters. LOL

Get it totally dry, put paper towel under each shaft seal and watch it every 4-6 hours in an effort to determine the source of the water.

Replace the bilge pump and consider the old pump as an emergency, spare pump.

Check, remove refresh the caulking for the pump strainer hold down screws.

Let's hope it is not the result of the ballast breaking up.

On some makes of older Taiwan trawlers, the hollow keel has a layer to form a shallower bilge.

Water gets in the keel and other routes from varying sources to include leaks and perforations of the shaft tube.

Any old screw hole or new crack in that shallow bilge leading to below can be the source.

While annoying and showing the "less than bulletproof" reputation some claim of these massively thick, old school hulls....you can enjoy many years of the boat with just an annoying leak unless it starts getting bad, fast.

As far as repairs, Clean it up and try to pinpoint the leak/ooze point.

Yes the leaks can be temporarily or permanently stopped while the boat is in the water, but easier when out and dried. A hole can also be drilled into the keel with drain plug so in future haulouts in freezing areas it can be drained.

As far as Navy ships not being fiberglass.....there are so many reasons why combatants of large size versus tiny recreational boats are made from different materials....keeping water on the outside isn't even or is probably the last one.

My boat had something similar. Turned out to be rain water trapped in some of the cavities trying to find a way out. Lifting the boat changed the angles and resulted in seepage from some imperfections in the glass. I bored some 3inch holes in some suspected areas, wet vac’d it then fitted inspection ports. Boring holes isn’t for the faint hearted btw. Know your boat and try to hook up with other owners of the same boat.

No need to bore 3 inch holes anywhere for any reason, inspection ports can be beneficial but for many things under the waterline more dangerous than useful.

Be very careful of advice offered by people that have experience with one or two boats they owned versus a commercial operator with many.

You say that but it some cases, and I mean some which I did clarify as doing your homework. Water does accumulate and unless you want it to stay there, and unless the designers meant it to be that way then perhaps there are other options. But as I said, know your boat and try to connect with other owners who may have already been there. Like myself.

psneeld said:

No need to bore 3 inch holes anywhere for any reason, inspection ports can be beneficial but for many things under the waterline more dangerous than useful.

Be very careful of advice offered by people that have experience with one or two boats they owned versus a commercial operator with many.

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You say that but it some cases, and I mean some which I did clarify as doing your homework. Water does accumulate and unless you want it to stay there, and unless the designers meant it to be that way then perhaps there are other options. But as I said, know your boat and try to connect with other owners who may have already been there. Like myself.

Oh I too did my homework. About 8 months worth calling and contacting owners and yards all over the US. I had pretty severe bottom issues and thought I might fix it to "new"..... so I wanted answers before needing to cut access holes all over.

The consensus was the way most of these boats were built, the cost of the fixes and final success was probably never worth it considering how many 30 to 50+ year old boats haven't fallen apart.

The probable sources of water are fairly well known and I see no advantage to boring 3 inch holes to find whats there. Smaller holes are more easily repaired, can tell you the same info and even there a max of 2 smaller holes can get one started.

The big thing here to me is whether we are talking drilling inspe tion holes into hard to see places within the hull or through the false bilge into the hollow keel or into the keel from the outside.

HopCar said:

I think the first step is to remove that old bilge pump and switch base. Then give the area a good cleaning so you can get a better idea of where the water is coming from. It’s possible that the bilge pump screws are too long and the sealant on them has failed.

Click to expand...

I agree. Partly because I hate to see things installed that aren't working or no longer used. It's also easier to clean the space.

However, if I thought that the water might be coming from a screw that is too long and has possibly penetrating the hull, I certainly wouldn't remove it while the boat is IN the water.

I'd also ask myself why there was a bilge pump removed from a location that clearly has the ability and propensity to collect water.

I have a similar sump as you in my GB36 bilge. I mounted my pump low in the bottom and the float switch at the next level. Manual override at the bilge switch to suck out the water below the float switch. I keep a turkey baster with a small hose on it by my batteries. I'm able to suck out the last 1/2 cup the bilge pump can't get. I do have a check valve approx a foot from the pump. Nice and dry..

A late arrival to this thread.
I, too, have a slow seawater leak appearing from under the bilge. I think it is probably a stern tube problem leaking into the hollow keel and then finding its way up through the keel cover.
I would like to fit a "sump" into the top of the keel - this way I could pump the water out without having it pooling in the flat bilge bottom.
Any thoughts on this?

Nick

If sealing is needed Total Boat has underwater epoxy that will seal even if it is seaping.

Wear good gloves !!!

Even fiberglass will shrink and swell. Through hulls might leak a bit until the glass swells a bit. You may have a tiny flaw in the glass that the old paint actually sealed. There could be other sources.

Give it a week or longer, my bet is that it will stop seeping.

As for the flaking, it is probably a non slip paint that it peeling off.

pete