Another way to get the thru-hull off is to grind the mushroom down. Being careful you can get it down to the threaded shaft portion. After which, you can push the whole assembly into the boat.
Good point. On stubborn seacocks where there is not space inside to swing a large pipe wrench I also cut off the mushroom head from outside using an angle grinder with metal cutting disc held at a 90 degree angle the the mushroom head. I make several cuts and then chisel off the pieces until the head is gone.
Great video! Want to do this to all my seacocks but don’t know the expense will have to look into it, I’d do all the work myself as that’s the best part of owning a boat but I think my boat has way too many seacocks for its size and Id want to glass over a few if I got into that project and I definitely don’t want to get into that this year.
I didn't see you use the nut for the thru-hull fitting. Did you just epoxy the backing pad to the hull and then bolt the valve to the backing plate? Then screwed the fitting into the valve? No nut or Teflon sealer on the fitting?
The nuts are discarded to the recycle bin. They are only used when someone decides not to use a proper seacock but to just screw a ball shut-off valve with no flanged base direct onto the mushroom held by the mushroom nut. In our case the backing plate is epoxied to the hull (or with a strong adhesive such as 5200), the base of the seacock is held by the three bolts in the backing plate and by the mushroom thru-hull threaded into the base. Yes we apply sealant to the threads of the thru-hull during final assembly.
I bought the Groco seacock and thru hull. Can somebody explain to me why those parts dont come with the bolts that attach seacock to backing plate? Now I have to guess what size/length of bolt to buy that will fit.
I don't use it but not a serious problem if you do since seacocks can withstand the torque of a pipe wrench to remove them if stuck on with 5200, unlike some other hardware and gelcoat. I generally use Life-caulk (polysulfide) but there are other suitable sealants available like Sikaflex 291. I have used 5200 between the backing block and hull if I don't use thickened epoxy since in that area you do want an adhesive and not just a sealant.
at about 6:54 you say that you can put a counter sunk bolt thru the backing plate sticking up. How does that work if you need to thread the seacock on to the thru hull. the bolts would prevent that from turning.
It doesn't matter if the backing block is fixed in position or not because the mushroom thru-hull is turned from outside to tighten it into the seacock. The mushroom has bosses inside that allow you to get a grip on it with a flat plate or chisel and then turn that plate with a wrench.
Do you know the three bolts from the seacock to the back pad what torque should these bolts be torque at and the through hull itself should there be a torque as well to the seacock? I like to torque everything I build for the purpose of not over tightening bolts and stripping stuff out, looks like you did about 3 ft pounds of torque but is there a torque spec anywhere? What a rule of thumb how many years are the seacocks good for or do you wait till they start to seep then change them out?
I know there are certain jobs where it's important to quantify how tight is tight but I rarely use a torque wrench because for most jobs such as this it isn't needed. Everything is bedded in sealant and the three nuts are nyloks so no danger of coming loose after tightening. As for overtightening that's not possible with short-handled wrenches. A long torque wrench that I'm familiar with also won't fit in some of the spaces where seacocks are located. If a seacock is visibly leaking I just replace it. If I suspect a leak inside then I pop off the hose to confirm and then replace the seacock. I rarely see a seacock that is installed properly needing replacement and I expect 20+ years of service in most cases. Often a problem is barnacle buildup inside when valves are not regularly turned. More often I see old ball valves screwed onto thru-hulls that look suspicious from age or ancient leaking tapered seacocks that could possibly be resurrected but generally are so old and worn it's not worth the trouble.
@@atomvoyager What are the things that can be done when there's barnacle buildup inside when valves are not regularly turned, and the valves won't fully close? Thanks in advance.
@@island663 A bottom cleaning diver, or yourself, will stick a tool such as a large screw driver in from below and knock out any barnacles or oyster shells. If the handle still won't turn, I'd wait until next haulout and disassemble or replace if needed. I've never had them jam that bad though unless they were very old of unknown date from a previous owner. What is common though is to have the flimsy plastic handle snap off in your hand when barnacles grow inside a marelon seacock, which is the main reason I rarely use them except on a trailer sailer that isn't in the water long term.
Question: when you screw the mushroom from the outside, do you tighten down or do you leave a little bit of the sealant like about an 8 inch overnight so that when you tighten from the inside, you have a rubber seal and not all squeezed out
Some people recommend that for deck fittings but that won't work on a seacock. The reason I don't do deck fittings that way is partly because you have to be very careful to turn only the nut and not the fastener or you risk breaking the seal. The other reason is it is generally not needed because you will countersink the deck hole so that some sealant always remains along that beveled edge. On seacocks you should drill the hole in the hull about 1/8" larger than the mushroom thru-hull and that is where the seal is made and so it can't squeeze out during tightening. You won't be able to turn the seacock because it is bound by the three bolts coming up through the flanged base. If you come back a day later not only can you not tighten the base but you can't turn the thru-hull and if you tighten the nuts on the base then you break the seal of the thru-hull.
I purchased these parts at a good discount through my West Marine wholesale account. I'm not sure if their retail prices are competitive so you need to check other suppliers to compare.
I noticed you don't put any sealant on the upper side of the mushroom's thread. I have seen other people doing it and I'm wondering what is better. Any suggestion?
I apply sealant up about 1" on threads from mushroom head which is slightly more than hull thickness and enough for a good seal. Adding sealant higher up the threads doesn't do anything anyway and just makes future removal more difficult. You can apply more if unsure but the extra will just squeeze out anyway and make a bigger mess.
@@atomvoyager i was afraid that water could find a way through the thread between the seacock and the truhull from inside. I'm replacing eleven of them, I admit I'm quite stressed :-/
@@ontyposrl You're right. I forgot to mention that i also put some sealant on the base of the seacock or on top the backing plate. I think that is better than just putting it way up on the threads but you can also do that.
I drill the holes so there is about 1/8" gap all around and fill the gap with sealant. That gap may be slightly larger sometimes depending on the availability of standard hole saw sizes for that seacock size. I think a tight fit has no advantage here and if loose it's easier to get the threads to line up with the backing block and its bolts.
You don't say if you want the parts cost to do yourself or parts and labor having a boatyard do the job. The parts for ten seacocks would cost about $1,900 retail and a couple hundred more if you need the backing plates. Labor would be about 2 hours for each seacock. If you just ask the yard to do it they may install a cheaper version consisting of ball valves screwed onto mushroom thru-hulls so you need to specify exactly what you want first. Maybe show them this video and ask them if they can do the same.
It's a type of PVC foam board. They're pricey though so I often just make similar ones from G10 fiberglass board. www.groco.net/products/valves-seacocks/accessories/backing-blocks
There's some info on this online that should pop up in a search that includes seacocks. For example, here's a discussion with the consensus being don't bother to bond seacocks at all. I'm not sure of what and why you are bonding though. www.cruisersforum.com/forums/f55/grounding-thu-hull-fittings-211574.html
Ur vids are so useful. Always nice to watch someone who knows what there doing. Thanks
I have used several of your videos in my own refit. This one included. I learned what to buy and how to install it the right way. Thank you.
Thanks. I'll be tackling this job this summer and found this helpful.
What a great presentation for a novice like me! Thank-you.
Another great instructional video, thanks for taking the time to share your wisdom!
I was just literally thinking about replacing seacocks and lookie here, a great how to!
Thanks. Very clear and informative.
Love your video's... just outstanding
Great info once again. Thank you.
Another way to get the thru-hull off is to grind the mushroom down. Being careful you can get it down to the threaded shaft portion. After which, you can push the whole assembly into the boat.
Good point. On stubborn seacocks where there is not space inside to swing a large pipe wrench I also cut off the mushroom head from outside using an angle grinder with metal cutting disc held at a 90 degree angle the the mushroom head. I make several cuts and then chisel off the pieces until the head is gone.
Thank you
Great video! Want to do this to all my seacocks but don’t know the expense will have to look into it, I’d do all the work myself as that’s the best part of owning a boat but I think my boat has way too many seacocks for its size and Id want to glass over a few if I got into that project and I definitely don’t want to get into that this year.
Thank you!
Super helpful. I wish we could have seen what you did on the outside to create the perfect white circle. Fiberglass I guess…
The white circle outside is just Interprotect 2000e epoxy primer.
I didn't see you use the nut for the thru-hull fitting. Did you just epoxy the backing pad to the hull and then bolt the valve to the backing plate? Then screwed the fitting into the valve? No nut or Teflon sealer on the fitting?
The nuts are discarded to the recycle bin. They are only used when someone decides not to use a proper seacock but to just screw a ball shut-off valve with no flanged base direct onto the mushroom held by the mushroom nut. In our case the backing plate is epoxied to the hull (or with a strong adhesive such as 5200), the base of the seacock is held by the three bolts in the backing plate and by the mushroom thru-hull threaded into the base. Yes we apply sealant to the threads of the thru-hull during final assembly.
Excellent
I bought the Groco seacock and thru hull. Can somebody explain to me why those parts dont come with the bolts that attach seacock to backing plate? Now I have to guess what size/length of bolt to buy that will fit.
How did you hold the backing block in place when you epoxied it to the hull? Thanks for the video.
The thickened epoxy may hold it on its own because the backing plates are light but I usually tape it with masking tape or duct tape until it's cured.
Thanks.
I see a lot of installers on YT using 5200 on these seacocks. That is very permanent! Is there a more flexible sealant that could be used instead?
I don't use it but not a serious problem if you do since seacocks can withstand the torque of a pipe wrench to remove them if stuck on with 5200, unlike some other hardware and gelcoat. I generally use Life-caulk (polysulfide) but there are other suitable sealants available like Sikaflex 291. I have used 5200 between the backing block and hull if I don't use thickened epoxy since in that area you do want an adhesive and not just a sealant.
at about 6:54 you say that you can put a counter sunk bolt thru the backing plate sticking up. How does that work if you need to thread the seacock on to the thru hull. the bolts would prevent that from turning.
It doesn't matter if the backing block is fixed in position or not because the mushroom thru-hull is turned from outside to tighten it into the seacock. The mushroom has bosses inside that allow you to get a grip on it with a flat plate or chisel and then turn that plate with a wrench.
I've always heard that brass on a boat was bad because it corrodes, and bronze was better. Would stainless nuts be better?
I may have mistakenly said brass but I assume they are bronze.
Do you know the three bolts from the seacock to the back pad what torque should these bolts be torque at and the through hull itself should there be a torque as well to the seacock? I like to torque everything I build for the purpose of not over tightening bolts and stripping stuff out, looks like you did about 3 ft pounds of torque but is there a torque spec anywhere? What a rule of thumb how many years are the seacocks good for or do you wait till they start to seep then change them out?
I know there are certain jobs where it's important to quantify how tight is tight but I rarely use a torque wrench because for most jobs such as this it isn't needed. Everything is bedded in sealant and the three nuts are nyloks so no danger of coming loose after tightening. As for overtightening that's not possible with short-handled wrenches. A long torque wrench that I'm familiar with also won't fit in some of the spaces where seacocks are located. If a seacock is visibly leaking I just replace it. If I suspect a leak inside then I pop off the hose to confirm and then replace the seacock. I rarely see a seacock that is installed properly needing replacement and I expect 20+ years of service in most cases. Often a problem is barnacle buildup inside when valves are not regularly turned. More often I see old ball valves screwed onto thru-hulls that look suspicious from age or ancient leaking tapered seacocks that could possibly be resurrected but generally are so old and worn it's not worth the trouble.
@@atomvoyager What are the things that can be done when there's barnacle buildup inside when valves are not regularly turned, and the valves won't fully close? Thanks in advance.
@@island663 A bottom cleaning diver, or yourself, will stick a tool such as a large screw driver in from below and knock out any barnacles or oyster shells. If the handle still won't turn, I'd wait until next haulout and disassemble or replace if needed. I've never had them jam that bad though unless they were very old of unknown date from a previous owner. What is common though is to have the flimsy plastic handle snap off in your hand when barnacles grow inside a marelon seacock, which is the main reason I rarely use them except on a trailer sailer that isn't in the water long term.
Question: when you screw the mushroom from the outside, do you tighten down or do you leave a little bit of the sealant like about an 8 inch overnight so that when you tighten from the inside, you have a rubber seal and not all squeezed out
Some people recommend that for deck fittings but that won't work on a seacock. The reason I don't do deck fittings that way is partly because you have to be very careful to turn only the nut and not the fastener or you risk breaking the seal. The other reason is it is generally not needed because you will countersink the deck hole so that some sealant always remains along that beveled edge. On seacocks you should drill the hole in the hull about 1/8" larger than the mushroom thru-hull and that is where the seal is made and so it can't squeeze out during tightening. You won't be able to turn the seacock because it is bound by the three bolts coming up through the flanged base. If you come back a day later not only can you not tighten the base but you can't turn the thru-hull and if you tighten the nuts on the base then you break the seal of the thru-hull.
Where did you purchase your valves? Thank you
I purchased these parts at a good discount through my West Marine wholesale account. I'm not sure if their retail prices are competitive so you need to check other suppliers to compare.
What did you use for the backing plate to hull? 5200?
I used thickened epoxy - resin with West System 406 silica added. You can also use 5200 if you prefer.
I noticed you don't put any sealant on the upper side of the mushroom's thread. I have seen other people doing it and I'm wondering what is better. Any suggestion?
I apply sealant up about 1" on threads from mushroom head which is slightly more than hull thickness and enough for a good seal. Adding sealant higher up the threads doesn't do anything anyway and just makes future removal more difficult. You can apply more if unsure but the extra will just squeeze out anyway and make a bigger mess.
@@atomvoyager i was afraid that water could find a way through the thread between the seacock and the truhull from inside. I'm replacing eleven of them, I admit I'm quite stressed :-/
@@ontyposrl You're right. I forgot to mention that i also put some sealant on the base of the seacock or on top the backing plate. I think that is better than just putting it way up on the threads but you can also do that.
Did you drill that hole TOO large for your through hull fitting? It looked really loose when you test fitted it.
I drill the holes so there is about 1/8" gap all around and fill the gap with sealant. That gap may be slightly larger sometimes depending on the availability of standard hole saw sizes for that seacock size. I think a tight fit has no advantage here and if loose it's easier to get the threads to line up with the backing block and its bolts.
I have a yacht that needs to replace 10 Thur hall.
Do you have idea how much should be cost?
You don't say if you want the parts cost to do yourself or parts and labor having a boatyard do the job. The parts for ten seacocks would cost about $1,900 retail and a couple hundred more if you need the backing plates. Labor would be about 2 hours for each seacock. If you just ask the yard to do it they may install a cheaper version consisting of ball valves screwed onto mushroom thru-hulls so you need to specify exactly what you want first. Maybe show them this video and ask them if they can do the same.
Thank you
Is it fiberglass those backing pads?
It's a type of PVC foam board. They're pricey though so I often just make similar ones from G10 fiberglass board. www.groco.net/products/valves-seacocks/accessories/backing-blocks
"Bonding wire to zinc anode"
I'm looking for information on this concept. Can anyone reccomend a vid/channel/info source??
There's some info on this online that should pop up in a search that includes seacocks. For example, here's a discussion with the consensus being don't bother to bond seacocks at all. I'm not sure of what and why you are bonding though.
www.cruisersforum.com/forums/f55/grounding-thu-hull-fittings-211574.html