Spartan Seacock-Thruhull Disassembly/Removal

[Larry DeMers]

Hi,

I am going to remove a seacock and it's thru-hull fitting on our CD30, and want to confirm the removal steps with someone that has done this before.

I know there was a thread about this earlier, but cannot find it when the keywords seacock and thruhull are used for the search. It must have been buried in a discussion of another topic.

The way I recall the construction of the seacock/thruhull is with the thruhull being attached to the hull from the outside with two bolts, that go through the fiberglass, thru the backing block on the inside, and then thru the seacock, which was screwed down on to the thru hulls tailpiece.

Is this essentially correct? Is there an adhesive or a sealant between the thru-hull and the boats outside skin, and what is the best way to break this bond when removing the thru hull?

Larry DeMers
s/v DeLaMer
Cape Dory 30 ~~~Sailing Lake Superior~~~





demers@sgi.com

[John R.]

Hi,

I am going to remove a seacock and it's thru-hull fitting on our CD30, and want to confirm the removal steps with someone that has done this before.

I know there was a thread about this earlier, but cannot find it when the keywords seacock and thruhull are used for the search. It must have been buried in a discussion of another topic.

The way I recall the construction of the seacock/thruhull is with the thruhull being attached to the hull from the outside with two bolts, that go through the fiberglass, thru the backing block on the inside, and then thru the seacock, which was screwed down on to the thru hulls tailpiece.

Is this essentially correct? Is there an adhesive or a sealant between the thru-hull and the boats outside skin, and what is the best way to break this bond when removing the thru hull?

Larry DeMers
s/v DeLaMer
Cape Dory 30 ~~~Sailing Lake Superior~~~

Yeah Larry, you generally have it correct with a couple of exceptions.

The thru-hull is threaded into the seacock body via the hole through the hull and backing block material. The thru-hull is not bolted, only the seacock and backing block are. Caulking if done properly is usually a polysulfide such as LifeCaulk. The caulk is applied between the thru-hull flange and the hull and at the base of the threads where they meet the flange. It is also placed between the backing block and the hull. Another application is applied between the seacock body and the backing plate and on the bolt threads and around their heads before installing. I recommend nylock nuts on the bolts.

Understand that the thru-hull is the last thing installed. The "seacock does not screw down onto the thru-hull" as you remarked. The thru-hull screws up into the seacock after the seacock is completely installed. The first step is to trial fit everything before doing the actual install. If you are installing a new thru-hull you may need to shorten it, that's why you need to do a trial fit first.

Install the seacock and backing block first and use the thru-hull if necessary to line up the components if there is any play in the alignment of the holes that will receive the thru-hull. As you tighten down the bolts that secure the seacock in place excess caulking will squeeze out into the hole for the thru-hull. Clean out most of it and be careful not to smear it up into the seacock body. Try and smear an even amount all around the inside edge of the hull and backing block hole. Apply a small amount of anti-seize compound to the upper threads of the thru-hull that will engage the seacock. That will make it easier to remove in the future. Apply a liberal bead of caulk to the entire flange area of the thru-hull and thread it into the seacock. Tighten with a thru-hull wrench or use a piece of 1/4" flat steel that will fit into the thru-hull and engage the nibs. Then just clean up the excess polysulfide with a latex squeege and mineral spirits.

If the previous installer used polysulfide you will be able to break the seal bond by unscrewing the thru-hull with the thru-hull wrench or the piece of steel mentioned above. If they screwed up and used 5200 or any other polyurethane you know you will have a very difficult time removing the thru-hull.

[Ed Rant]

I am going to remove a seacock and it's thru-hull fitting on our CD30, and want to confirm the removal steps with someone that has done this before...:

Larry:
If your through-hull turns out to be hard to remove, here's a method recommended by Don Casey in his book "This Old Boat". It requires removing the seacock first. I didn't have to do mine this way but it sounds like it ought to work. I'll paraphrase: Get a large bolt (3/8 or 1/2") about 4" longer than the through-hull, along with a nut and pair of washers too big to pass through the fitting. Slide one of the washers onto the bolt and from the inside of the boat pass the bolt through the fitting, seating the washer flat on the fitting. Outside the boat, pass the bolt through a short length of 2x4 and fit the second washer and nut. Support the 2x4 on both sides of the fitting with a couple of 2x4 blocks. As you tighten the nut the bolt will pull the fitting from the hull. This is similar to using a steering wheel puller on an automobile. Good luck on your project.

Ed



cd27@txdirect.net

[Larry DeMers]

Ed and John,

Thanks for those suggestions..all of which I will use. Ed..good idea with that puller, if they did use 5200 (I hope not).


John, I am glad you mentioned the assembly aspect of the seacock, because I was able to mentally picture the exploded diagram as you wrote it. well done. Now to find a 1/4" steel bar..might have something in the garage even.

If it weren't for that piece of advice guys, I would have started off with the assumption that the body of the seacock screwed down onto the tail piece of the thru-hull, and so would have had some problems getting it off.


Thanks again..is this a great Board or what!?!


Larry DeMers
s/v DeLaMer
Cape Dory 30 ~~~Sailing Lake Superior~~~

Hi,

I am going to remove a seacock and it's thru-hull fitting on our CD30, and want to confirm the removal steps with someone that has done this before.

I know there was a thread about this earlier, but cannot find it when the keywords seacock and thruhull are used for the search. It must have been buried in a discussion of another topic.

The way I recall the construction of the seacock/thruhull is with the thruhull being attached to the hull from the outside with two bolts, that go through the fiberglass, thru the backing block on the inside, and then thru the seacock, which was screwed down on to the thru hulls tailpiece.

Is this essentially correct? Is there an adhesive or a sealant between the thru-hull and the boats outside skin, and what is the best way to break this bond when removing the thru hull?

Larry DeMers
s/v DeLaMer
Cape Dory 30 ~~~Sailing Lake Superior~~~

Yeah Larry, you generally have it correct with a couple of exceptions.

The thru-hull is threaded into the seacock body via the hole through the hull and backing block material. The thru-hull is not bolted, only the seacock and backing block are. Caulking if done properly is usually a polysulfide such as LifeCaulk. The caulk is applied between the thru-hull flange and the hull and at the base of the threads where they meet the flange. It is also placed between the backing block and the hull. Another application is applied between the seacock body and the backing plate and on the bolt threads and around their heads before installing. I recommend nylock nuts on the bolts.

Understand that the thru-hull is the last thing installed. The "seacock does not screw down onto the thru-hull" as you remarked. The thru-hull screws up into the seacock after the seacock is completely installed. The first step is to trial fit everything before doing the actual install. If you are installing a new thru-hull you may need to shorten it, that's why you need to do a trial fit first.

Install the seacock and backing block first and use the thru-hull if necessary to line up the components if there is any play in the alignment of the holes that will receive the thru-hull. As you tighten down the bolts that secure the seacock in place excess caulking will squeeze out into the hole for the thru-hull. Clean out most of it and be careful not to smear it up into the seacock body. Try and smear an even amount all around the inside edge of the hull and backing block hole. Apply a small amount of anti-seize compound to the upper threads of the thru-hull that will engage the seacock. That will make it easier to remove in the future. Apply a liberal bead of caulk to the entire flange area of the thru-hull and thread it into the seacock. Tighten with a thru-hull wrench or use a piece of 1/4" flat steel that will fit into the thru-hull and engage the nibs. Then just clean up the excess polysulfide with a latex squeege and mineral spirits.

If the previous installer used polysulfide you will be able to break the seal bond by unscrewing the thru-hull with the thru-hull wrench or the piece of steel mentioned above. If they screwed up and used 5200 or any other polyurethane you know you will have a very difficult time removing the thru-hull.

demers@sgi.com

[Ken Coit]

Larry,

I am travelling without my latest issues of Cruising World and Sail, but I am pretty sure that in at least one of those there is an ad for a new solvent that attacks 5200. Or maybe it was Practical Sailor? Anyway, if no one else can find it, I will post it when I get back to Raleigh.

Ken Coit
S/V Parfait CD-36 #84

Ed and John,

Thanks for those suggestions..all of which I will use. Ed..good idea with that puller, if they did use 5200 (I hope not).


John, I am glad you mentioned the assembly aspect of the seacock, because I was able to mentally picture the exploded diagram as you wrote it. well done. Now to find a 1/4" steel bar..might have something in the garage even.

If it weren't for that piece of advice guys, I would have started off with the assumption that the body of the seacock screwed down onto the tail piece of the thru-hull, and so would have had some problems getting it off.


Thanks again..is this a great Board or what!?!


Larry DeMers
s/v DeLaMer
Cape Dory 30 ~~~Sailing Lake Superior~~~

Hi,

I am going to remove a seacock and it's thru-hull fitting on our CD30, and want to confirm the removal steps with someone that has done this before.

I know there was a thread about this earlier, but cannot find it when the keywords seacock and thruhull are used for the search. It must have been buried in a discussion of another topic.

The way I recall the construction of the seacock/thruhull is with the thruhull being attached to the hull from the outside with two bolts, that go through the fiberglass, thru the backing block on the inside, and then thru the seacock, which was screwed down on to the thru hulls tailpiece.

Is this essentially correct? Is there an adhesive or a sealant between the thru-hull and the boats outside skin, and what is the best way to break this bond when removing the thru hull?

Larry DeMers
s/v DeLaMer
Cape Dory 30 ~~~Sailing Lake Superior~~~

Yeah Larry, you generally have it correct with a couple of exceptions.

The thru-hull is threaded into the seacock body via the hole through the hull and backing block material. The thru-hull is not bolted, only the seacock and backing block are. Caulking if done properly is usually a polysulfide such as LifeCaulk. The caulk is applied between the thru-hull flange and the hull and at the base of the threads where they meet the flange. It is also placed between the backing block and the hull. Another application is applied between the seacock body and the backing plate and on the bolt threads and around their heads before installing. I recommend nylock nuts on the bolts.

Understand that the thru-hull is the last thing installed. The "seacock does not screw down onto the thru-hull" as you remarked. The thru-hull screws up into the seacock after the seacock is completely installed. The first step is to trial fit everything before doing the actual install. If you are installing a new thru-hull you may need to shorten it, that's why you need to do a trial fit first.

Install the seacock and backing block first and use the thru-hull if necessary to line up the components if there is any play in the alignment of the holes that will receive the thru-hull. As you tighten down the bolts that secure the seacock in place excess caulking will squeeze out into the hole for the thru-hull. Clean out most of it and be careful not to smear it up into the seacock body. Try and smear an even amount all around the inside edge of the hull and backing block hole. Apply a small amount of anti-seize compound to the upper threads of the thru-hull that will engage the seacock. That will make it easier to remove in the future. Apply a liberal bead of caulk to the entire flange area of the thru-hull and thread it into the seacock. Tighten with a thru-hull wrench or use a piece of 1/4" flat steel that will fit into the thru-hull and engage the nibs. Then just clean up the excess polysulfide with a latex squeege and mineral spirits.

If the previous installer used polysulfide you will be able to break the seal bond by unscrewing the thru-hull with the thru-hull wrench or the piece of steel mentioned above. If they screwed up and used 5200 or any other polyurethane you know you will have a very difficult time removing the thru-hull.

parfait@nc.rr.com

[Larry DeMers]

Ken,

I found that product listed in B/US catalog last night, and ordered the spray this am. It is called "Anti Bond 2015" and goes for $12.99, with a P/n of 401800.

Since I got this advice from several guys, I assume this means that those damn things are stuck on with 5200!? I have ordered a cartridge of 4200 (half the strength of 5200) to caulk the new sensor in with. Do you see any problem with this idea?

Thanks again,

Larry DeMers
s/v DeLaMer

Larry,

I am travelling without my latest issues of Cruising World and Sail, but I am pretty sure that in at least one of those there is an ad for a new solvent that attacks 5200. Or maybe it was Practical Sailor? Anyway, if no one else can find it, I will post it when I get back to Raleigh.

Ken Coit
S/V Parfait CD-36 #84

Ed and John,

Thanks for those suggestions..all of which I will use. Ed..good idea with that puller, if they did use 5200 (I hope not).


John, I am glad you mentioned the assembly aspect of the seacock, because I was able to mentally picture the exploded diagram as you wrote it. well done. Now to find a 1/4" steel bar..might have something in the garage even.

If it weren't for that piece of advice guys, I would have started off with the assumption that the body of the seacock screwed down onto the tail piece of the thru-hull, and so would have had some problems getting it off.


Thanks again..is this a great Board or what!?!


Larry DeMers
s/v DeLaMer
Cape Dory 30 ~~~Sailing Lake Superior~~~

Yeah Larry, you generally have it correct with a couple of exceptions.

The thru-hull is threaded into the seacock body via the hole through the hull and backing block material. The thru-hull is not bolted, only the seacock and backing block are. Caulking if done properly is usually a polysulfide such as LifeCaulk. The caulk is applied between the thru-hull flange and the hull and at the base of the threads where they meet the flange. It is also placed between the backing block and the hull. Another application is applied between the seacock body and the backing plate and on the bolt threads and around their heads before installing. I recommend nylock nuts on the bolts.

Understand that the thru-hull is the last thing installed. The "seacock does not screw down onto the thru-hull" as you remarked. The thru-hull screws up into the seacock after the seacock is completely installed. The first step is to trial fit everything before doing the actual install. If you are installing a new thru-hull you may need to shorten it, that's why you need to do a trial fit first.

Install the seacock and backing block first and use the thru-hull if necessary to line up the components if there is any play in the alignment of the holes that will receive the thru-hull. As you tighten down the bolts that secure the seacock in place excess caulking will squeeze out into the hole for the thru-hull. Clean out most of it and be careful not to smear it up into the seacock body. Try and smear an even amount all around the inside edge of the hull and backing block hole. Apply a small amount of anti-seize compound to the upper threads of the thru-hull that will engage the seacock. That will make it easier to remove in the future. Apply a liberal bead of caulk to the entire flange area of the thru-hull and thread it into the seacock. Tighten with a thru-hull wrench or use a piece of 1/4" flat steel that will fit into the thru-hull and engage the nibs. Then just clean up the excess polysulfide with a latex squeege and mineral spirits.

If the previous installer used polysulfide you will be able to break the seal bond by unscrewing the thru-hull with the thru-hull wrench or the piece of steel mentioned above. If they screwed up and used 5200 or any other polyurethane you know you will have a very difficult time removing the thru-hull.

demers@sgi.com