Bilge Water and Encapsulated Keel

[anjolain]

Originally Posted by Fiberglass1Inc

I may have misunderstood your problem. If there is water inside the void at the aft end of the keel it is unlikely that the hvac is going to pull any moisture through multiple layers of laminate, typically pretty thick in way of the keel. From the photo it looks like a void in the last inside layer of glass. If that's the case just make a clay doughnut slightly larger than the hose of a wet-dry shop vac, plce the hose and doughnut above the void and let it run. Do that off and on for a couple of days and you will remove the moisture. I thought you were trying to remove moisture from the hull in order to do a blister job.

The guy doing the HotVac repairs at the yard suggested that we could also drill holes into the keel laminate and then apply HotVac treatment. Could that be efficient in removing the moisture from the keel?

[atoll]

Originally Posted by anjolain

The guy doing the HotVac repairs at the yard suggested that we could also drill holes into the keel laminate and then apply HotVac treatment. Could that be efficient in removing the moisture from the keel?

it could become a very expensive repair,when you find at the end of the winter the keel is still seeping water,and have no way to reseal effectively the many holes you will have to drill .

but it could be a very nice job for someone if they are charging by the hour

[Fiberglass1Inc]

If you drill holes you would have to seal the holes on the inside in order to pull vacuum. That might be easier said than done. And, typically, there is no moisture (water ingress) in the woven roving or whatever structural glas is in the hull. The water ingress usually occurs in the CSM "skin coat" on the outside. In your photograph, the problem area appears to be a different color, indicating a simple void in the filler used in the original construction. If this is the case, simply vacuum out any moisture and fill with epoxy as suggested before. Don't let anyone make a mountain out of your mole hill. I see that all the time and it pisses me off because it makes the owner think everybody is out to screw him.... he sells the boat and takes up golf. Another customer gone due to stupid greed!
If there really is a problem of some sort you will see hairline cracks and water traces or stains on the outside and circular fractures around the keel bolts on the inside.

[cburger]

Originally Posted by Fiberglass1Inc

If you drill holes you would have to seal the holes on the inside in order to pull vacuum. That might be easier said than done. And, typically, there is no moisture (water ingress) in the woven roving or whatever structural glas is in the hull. The water ingress usually occurs in the CSM "skin coat" on the outside. In your photograph, the problem area appears to be a different color, indicating a simple void in the filler used in the original construction. If this is the case, simply vacuum out any moisture and fill with epoxy as suggested before. Don't let anyone make a mountain out of your mole hill. I see that all the time and it pisses me off because it makes the owner think everybody is out to screw him.... he sells the boat and takes up golf. Another customer gone due to stupid greed!
If there really is a problem of some sort you will see hairline cracks and water traces or stains on the outside and circular fractures around the keel bolts on the inside.

Sage advice that probably won't be followed.

[Fiberglass1Inc]

"Forensic" fiberglass work - first you have to figure out what went wrong. Only then can you truly repair the problem.

[anjolain]

I appreciate your comments! I understand that there is a possibility of fixing something that is not really broken. On the other hand, I have to pay any way quite a lot for wintering in a boat shed, because she is going to have her teak deck renovated. Therefore, I think that this would be the best time to attack the keel issue as well. I do not mind for spending extra 1-2k for a repair, which would give peace of mind.

I know from the condensation trails, that there is probably some moisture in the keel. I do not believe that the whole keel would be full of water however. The boat is wintering in Northern Europe, where there is a freezing temperatures in winter. Thus, I do not like the idea of having water in the keel. The idea is to start by drilling a few holes into the suspect areas and see what comes out. "Atoll" well pointed out the risk of having a hole which keeps seeping water. This possibility needs definitely to be considered.

One possibility that I have heard of would be to inject acetone into the keel. Would that be helpful?

[Fiberglass1Inc]

Acetone is OK but often contaminated. Also it evaporates very quickly. In your case, the moisture may have seeped down into lots of cracks and spaces so I believe denatured alcohol would be a better choice. It hangs around (hydroscopic) for a longer time and therefore has a better chance of attracting more moisture from tiny little cracks and voids.

[perchance]

A Garboard Plug near the bottom of the keel will allow the keel to drain when the boat is on the hard. Inexpensive to buy and easy to install.

[Fiberglass1Inc]

Also, I wouldn't have any problem with drilling holes to facilitate drying, just be certain that the edges of the holes are well rounded, tapered out a few inches, filled and glassed over. All epoxy of course, nothing that ends in "ester"!

[levante]

I am working on a project exactly like this one only far more severe.. take this job very seriously if you dont fix it well it can lead to the delamination of your bilge walls goin up the sides of the boat. Fiberglass laminates don't take well to Salt water,Diesal,oil, ect... I dont know if your on the hard or not. If you are be sure to check your outer hull in the areas near the cracks/voids in your bilge. Or from the inside push against the bilge walls and make sure their not flexing excessively. This is a common occurring fault with deep bilges and encapsulated keels.. I don't know why they didn't use fillets before glassing over the ballast in the bilge. From what I've seen they add the ballast then cover it with Resin then glass over it add more resin then tab in a square edge to create the bilge sole. It works but it's a weak system.

[levante]

I would drill a few holes into the bottom of my keel to see if you have water seepage and to dry it out. Read some where in the postings that its hard to fill a drilled hole in the keel this is not true. It's very easy ! You countersink the holes inject them with acetone let that drain out then inject some Zylene or Mek p both very nasty (wear gloves) this is to try and make the Fiberglass resin sticky again. Then inject thickened epoxy. Over fill the holes and leave them proud of the hull. Sand them when the epoxy has set. If it makes you feel better grind the area the holes are in and epoxy a few layers of 6-10 oz cloth over the holes and feather the edges to blend in with the hull.. It's nearly the same process for your inside repair. Get a bendable drill extension you'll need it as I'm guessing it's going to be hard to get a drill into that tight crevice. Drill a bunch of holes round the area where you suspect the void to be.If you can suck water with a wet Vac from the outside holes then you have a vaccume and can suck acetone through the inside holes you drilled. I would suggest using a degreasing solution first then use the acetone. Tape off holes ect to get everything dry. Fill the outer holes first then useing the same method used to repair delaminated decks by taping and injecting resin fix the internal void/delam. Only difference is I would use (am using) coal tar epoxy for the repair. It sticks to everything !!! Even oily surfaces. Good luck.

[minaret]

I have a Hotvac system which I have been using for many years now. Don't worry, it will get your keel dry. The operator should start drying at the top of the keel and work down, drying both sides at once. Drill holes for only one set of vac pads at a time, or obviously you won't pull a vacuum. This also means the holes must be repaired as you go, before you put down the next set of pads. And that the interior glass must be intact and air tight or made to be so. It works great however, we've done it several times now. Have also dried saturated foam cores, it's an impressive machine, does a lot more than just drying solid lams. Don't pour any solvents, it's not good for the machine. Repairing holes even when weeping water is just boatyard basics, any pro can do it just fine. Just requires a heat gun and some fast moving with a really hot resin batch. But that won't be an issue for you, Hotvac should get it bone dry. You can't take moisture meter readings in way of a ballast keel, the metal will give a false positive every time. Since you cant get a moisture reading just run the Hotvac for two days on each pad spot instead of one. It'll be totally dry in a week or two, depending on if you are running the two-pad system or the four. Check their pads before they put them on and make sure there are no burn marks in the coil. We have had several pads burn up on us, but they are getting better. When they do go, often the short will cause a burn mark on the pad and hull which must be repaired. If they try to use a pad with a burn mark on it insist on new pads. Sometimes people try to stretch them because they aren't cheap. Watch the gauges and make sure the temps don't exceed 180F for any lengthy period of time. The vac gauges must pull less than 100, 40-60 is good vac, 20-30 is great vac. If they read over 100 find the air leak, it's wasted time unless your pulling good vac. Good luck!

[Jim Cate]

FWIW:

I would be kinda cautious about using a shop vac to pull acetone or other flammable solvent vapours through your keel. The unshielded motors in the vac spark like mad, and if the fuel:air ratio gets into the flammable range... well, you might not have to empty the vac's barrel ever again!

Cheers,

Jim

[knots2u]

Originally Posted by levante

If you can suck water with a wet Vac from the outside holes then you have a vaccume and can suck acetone through the inside holes you drilled.

As a fire fighter I have to say something here... I certainly would not advise someone vacuum a highly volatile flammable liquid such as acetone with a shop vac. Some kind of hand pump maybe but not a wet/dry vacuum. Boom boom out go the lights!

[Fiberglass1Inc]

Been there.... actually it was pretty spectacular when the vacuum blew up and the top section took off straight up. Thankfully, no people or boats were hurt, but there was a second or two when ya didn't know where it was gonna land........
Short story, dont use acetone to dry. It's volatile, often contaminated, evaporates too quickly to do much good. If you want to dry something on a salt water boat, start with fresh water rinse (too many reasons to go into here), vacuum out standing water (preferably hot vac if available), inject denatured alcohol, wait a few hours and see what you've got.
If you can demonstrate a more efficient method than this I would greatly appreciate any feed back.