Kamassi Butt Cat
- Thread starter Fish Taxi
- Start date
Hey Bennie/BFC I'd like your opinion on this please.
I'm not so sure that water in your foamed section of the hull is going to drain through to your bottled area or any drainage pipe that may be fitted below the foam. When I opened up the deck of my foam filled 21 ft butt, the newer foam in the bow section was holding pockets of water on top of the foam from water that had leaked from the deck. That water wasn't draining anywhere and the newer foam doesn't seem to absorb much water. The foam was also stuck to every bit of the hull so there are no channels between the foam and the hull where the water can drain through to the keel and into any drainage pipe.
And then the older foam that was to the stern that had become waterlogged was still waterlogged despite there being 2 bung holes for drainage in the transom. The only way that water is going to come out of the foam is with compression. Simple drainage isn't going to drain all the water out. Take a bath sponge as an example, you gotta squeeze it to get all the water out.
So I don't really see any major benefit in putting a bottled section around the transom or fitting drainage pipes along the keel. How is that trapped water supposed to drain through to these areas? Even older foam that has absorbed water is going to need compression to squeeze it out.
Would like some input from you guys on this. Cheers
I'm not so sure that water in your foamed section of the hull is going to drain through to your bottled area or any drainage pipe that may be fitted below the foam. When I opened up the deck of my foam filled 21 ft butt, the newer foam in the bow section was holding pockets of water on top of the foam from water that had leaked from the deck. That water wasn't draining anywhere and the newer foam doesn't seem to absorb much water. The foam was also stuck to every bit of the hull so there are no channels between the foam and the hull where the water can drain through to the keel and into any drainage pipe.
And then the older foam that was to the stern that had become waterlogged was still waterlogged despite there being 2 bung holes for drainage in the transom. The only way that water is going to come out of the foam is with compression. Simple drainage isn't going to drain all the water out. Take a bath sponge as an example, you gotta squeeze it to get all the water out.
So I don't really see any major benefit in putting a bottled section around the transom or fitting drainage pipes along the keel. How is that trapped water supposed to drain through to these areas? Even older foam that has absorbed water is going to need compression to squeeze it out.
Would like some input from you guys on this. Cheers
benniejordaan
Sealiner
Patrick wrote:
This is my opinion.
The water doesn't get sucked up like a bath sponge. In fact the foam resists water. But what happens is that with water in the hull, then the continious banging of the hull riding over water, water slowly seeps into the foam. Think of it as presurising the hull, forcing the water into the foam.
The idea is that if water acumulates on the foam, the water will displace off the top of the foam and have somewhere to run to. The idea of some bottles is that water can accumulate in the hollows between the bottles and allow for drainage when you pull the plugs.
After time, the foam does break down. Just like bottles that deteriorate and the absorbtion rate will go up over time which may explain why the older foam was water logged. But also, it had more exposure to water than the new foam.
My concern is with the water that gets in there but doesn't come out.
Here water can be channeled down the center.
Hi,
This is my opinion.
The water doesn't get sucked up like a bath sponge. In fact the foam resists water. But what happens is that with water in the hull, then the continious banging of the hull riding over water, water slowly seeps into the foam. Think of it as presurising the hull, forcing the water into the foam.
The idea is that if water acumulates on the foam, the water will displace off the top of the foam and have somewhere to run to. The idea of some bottles is that water can accumulate in the hollows between the bottles and allow for drainage when you pull the plugs.
After time, the foam does break down. Just like bottles that deteriorate and the absorbtion rate will go up over time which may explain why the older foam was water logged. But also, it had more exposure to water than the new foam.
My concern is with the water that gets in there but doesn't come out.
Here water can be channeled down the center.
benniejordaan wrote:
Exactly ,
Also the reason for the foam being glassed tight , and then a deck fitted afterwards on top. Drainage out of foam is impossible therefore the stern compartments filled with bottles to give water a designated area to go to, so where a bit of water gathers you can drain it, and start from scratch again , instead of a hull that accumulates and in time all is water logged and need grinders/drills /saws to rectify.
Patrick wrote:Hi,
This is my opinion.
The water doesn't get sucked up like a bath sponge. In fact the foam resists water. But what happens is that with water in the hull, then the continious banging of the hull riding over water, water slowly seeps into the foam. Think of it as presurising the hull, forcing the water into the foam.
The idea is that if water acumulates on the foam, the water will displace off the top of the foam and have somewhere to run to. The idea of some bottles is that water can accumulate in the hollows between the bottles and allow for drainage when you pull the plugs.
After time, the foam does break down. Just like bottles that deteriorate and the absorbtion rate will go up over time which may explain why the older foam was water logged. But also, it had more exposure to water than the new foam.
My concern is with the water that gets in there but doesn't come out.
Here water can be channeled down the center.
Exactly ,
Also the reason for the foam being glassed tight , and then a deck fitted afterwards on top. Drainage out of foam is impossible therefore the stern compartments filled with bottles to give water a designated area to go to, so where a bit of water gathers you can drain it, and start from scratch again , instead of a hull that accumulates and in time all is water logged and need grinders/drills /saws to rectify.
benniejordaan
Sealiner
I'm not saying that just foam is wrong. I am only stating my preference. I am sure the foam at the back gets it worst because of the natural stance of the boat "arse down" so water accumulates at the back.
But from my experience, ALL boats eventually take on some water. Some more than others. If it does, it would be nice to know about it before the guarantee is up and with plugs you are able to monitor it.
Go take a look at the pics of your boats being built, see who is working on them. When a certain "couldn't give a damn" drills holes into the keel, does he always A - care if he goes right through and B - tell the boss if he has? Has the joint between the deck and hull been done right? Boats move and twist and gaps get bigger. I would just like to know if it is taking on water instead of assuming it isn't.
But from my experience, ALL boats eventually take on some water. Some more than others. If it does, it would be nice to know about it before the guarantee is up and with plugs you are able to monitor it.
Go take a look at the pics of your boats being built, see who is working on them. When a certain "couldn't give a damn" drills holes into the keel, does he always A - care if he goes right through and B - tell the boss if he has? Has the joint between the deck and hull been done right? Boats move and twist and gaps get bigger. I would just like to know if it is taking on water instead of assuming it isn't.
benniejordaan wrote:
Its much easier , and cheaper foaming the whole hull but in my opinion better in the long run to have a hybrid of both - the exact configuration of how is still open for debate.
the deck is one place where water can come in but , the biggest culprit is keel strips. With a Monohull you have one but with a cat there are 2.
Fitting a Keelstrip is best to do before fitting the deck , in case of a hole going thru you can seal /glass it thick from the inside again but does it get done?
Its much easier , and cheaper foaming the whole hull but in my opinion better in the long run to have a hybrid of both - the exact configuration of how is still open for debate.
the deck is one place where water can come in but , the biggest culprit is keel strips. With a Monohull you have one but with a cat there are 2.
Fitting a Keelstrip is best to do before fitting the deck , in case of a hole going thru you can seal /glass it thick from the inside again but does it get done?
in stripping my butt cat, foam also had water on top, under the deck, this is from a boat standing on the hard for 7 years, so mostly rain water, water had ingressed and was and right through the foam. if squeezed / pressured water would come out. NO water came out the bungs, but the hull was FULL off water, I agree with Patrick here, water will not necessarily be able to make it to the keel to drain.
Ok the drainage area at the back will help with removing the water that's trapped between the deck and the foam. I'll be sure to give this idea consideration before I pour my foam. Will have to put the bow nice and high in the air on a 21ft for the trapped water to drain through to this area.
But no drainage will help remove water trapped in foam once its pushed in. Only excess water that is above the saturation point of the foam will begin to drain, by which point you'll have to replace the foam anyway.
But no drainage will help remove water trapped in foam once its pushed in. Only excess water that is above the saturation point of the foam will begin to drain, by which point you'll have to replace the foam anyway.
FishExcutnr
Sealiner
just bond keel strips, dont use screws. and surely bfc water is not gonna get to your foam or at least have a hard time, you have glassed it in before the deck was put on. thats the way to do it
benniejordaan
Sealiner
When parked on the trailer, you should always jack the jockey wheel out so the nose points up as high as possible. Those of you who do have plugs... Go try it, you might find a little more water come out.