Strange old thru-hulls

[hellosailor]

I can't see that it matters whether there are throughbolts (each one another hole in the hull and another thin bit of structure to worry about) or whether the entire fitting is held to the hull with a large spanner bolt around the inside of it. Or, screwed to the backing block which, in theory, has become an integral part of the hull anyway.

I'd suspect that once you draw up a list of how many new seacocks you need, what sizes they are, and you start looking for a preferred vendor for them, you'll find the limits on size and type make a lot of those decisions for you.<G>

By the way, if you ever bed a fitting like this in 3M's 5200? It takes quite some time to make a complete cure, but once it does...that's a structural bond, and you're not going to be able to remove the fitting without destroying it. A good thing, if that's your intent.

If you haven't done glass work before, West Systems Epoxy (a major US supplier for boaters, not West Marine) has extensive docs and pdfs about all this available online. And if you don't mind calling the US, also free tech support from genuine technical people. Good products, too.

[tyrol]

Okay, I'll get the 5200 as I doubt I'll ever want to remove these once I install them. I guess I'd better wait til it warms up a bit... And I'd rather just screw the flange to the backer rather than make more holes, so that's good too.

My glass experience has just started but I'm feeling pretty good about it (using West System Epoxy and the docs you mention). I've done some fairing to my lead keel and assorted dings on the hull, replaced some bulkhead tabbing, remounted most of my deck hardware properly and build a new battery compartment. Closing up the old thru-hulls seems like a combination of the above... I'll send completed photos for critiques!

This is certainly a major learning experience, but I'm loving it...

[Steve Rust]

tyrol
Don't be temted to use just staight resin. Add a high density filler. You may also have to do it in two steps as epoxy can get quite hot if too much is concentrated in a small area. Do the second layer after the first has cooled off but before it cures. I would recommend using 3M 4200 instead of 5200. Same sealing properties but it does allow for dissassembly in the future.

[tyrol]

Just a little update - started removing my thru-hulls and it turns out that most of them are just threaded pipe fibreglassed into the hull which I could just unscrew with a little effort. In other words about 1/4 inch of threads (no flange, no mushroom) holding the fixture in place! The good thing is that it will be easy to put a mushroom on after all and I can easily use existing holes rather than repairing them and creating new ones. Here's a photo of the raw water intake. Cheers, Ty.

[Steve Rust]

Thank god they don't "make em like they used to".

[hellosailor]

Ty, that is truly frightening. Was the built home-built by someone? Did the last owner have big floppy shoes, a big red fright wig, a red rubber nose, and answer to the name "Bozo" ?!

[tyrol]

Well it WAS the 60's! But seriously, I guess it's a lot of luck that she's still floating at 39 years old.

[David_Old_Jersey]

Yikes!

The good thing about doing the job yourself is that you will know that it has been done properly.

I am sure you have been Googling already, but.......



Seacock Removal and Replacement


Easy to spend someone else's money and time!, but I would suggest you also take the opportunity to replace the hoses. and as I am sure you know, a bit of heat will make them easier to fit.

Finally, you may want to consider fitting a "strainer" to the raw water intake from experiance they do stop plastic bags getting sucked up the intake!




- they also make them in plastic for a couple of quid.

Fix them on with small grub screws that only go enough into the hull to hold it on (not bolted or screwed through the hull!) - the idea being that even though a plastic bag may get sucked up against the intake and prevent the water inflow, when yer stop the engine it should drop off when the suction stops.

[GordMay]

David:
The excellent article doesn’t seem to mention sealing the edges of the hole, to prevent moisture intrusion into the solid laminate.

[Joli]

Originally Posted by David_Old_Jersey

Yikes!

The good thing about doing the job yourself is that you will know that it has been done properly.

I am sure you have been Googling already, but.......



Seacock Removal and Replacement


Easy to spend someone else's money and time!, but I would suggest you also take the opportunity to replace the hoses. and as I am sure you know, a bit of heat will make them easier to fit.

Finally, you may want to consider fitting a "strainer" to the raw water intake from experiance they do stop plastic bags getting sucked up the intake!




- they also make them in plastic for a couple of quid.

Fix them on with small grub screws that only go enough into the hull to hold it on (not bolted or screwed through the hull!) - the idea being that even though a plastic bag may get sucked up against the intake and prevent the water inflow, when yer stop the engine it should drop off when the suction stops.

Hate to be picky but.....

That is not a proper seacock and should not be used below the waterline. The thread of the thru hull is cut and you can get crevice corrosion in the area between the ball valve and the thru hull. If this happens and the valve breaks off between the thru hull and flange plate you have no way to close it other then a DC plug.

Install a proper seacock, thru bolt it, and mate it to a thru hull, double clamp it and close it when you leave the boat. This is bullet proof, dont skimp, most boats sink sitting at the dock while unatended.

I like the Appolo's better then the Groco's (we have both) The bolt hole pattern of the Appollo makes it easier to spin in the thru hull after the seacock is bolted to the hull. I also use 5200 for this job. If you ever have to take it apart put some heat to it, it'll spinn off.

Appollo

http://i3.ebayimg.com/04/i/05/17/7c/cb_1.JPG


Grocco


http://www.pyacht.net/online-store/s...BV_Seacock.gif

Prep



http://www.tritondaysailor.com/images/thholeinhull.jpg

Installed



http://www.landfall-marine.com/ps%20seacock.jpg


The question of bonding is well, a whole other subject. We don't but our surveyor says do.

[David_Old_Jersey]

oooops yer right, not my choice of fitting..........


I would normally have had a good look before posting something - must be more careful.

[tyrol]

So it is not proper just because it doesn't have the flange? Or does it have tapered threads? Or both? I was going to use the Marelon stuff and got the idera that either flange or no flange was acceptable...

[DeepFrz]

It should have the flange. The ones without a flange are "in line" valves for piping, not for thru hulls.

Deep

[tyrol]

Ummm, I bring this up because I've actually already bought some of the (expensive) Marelon flangeless ball valves, and I won't use them if they're not safe or not up to code, but I read that the ABYC used to require flanges on seacocks and doesn't anymore. Is that right?

I can certainly see why they're desirable for strength, but are they necessary if you have enough, and not too much, thread available on the thru-hull? These will be installed where there's no risk of being stepped on. Is there anything I'm missing?

Regardless, I'm glad for all advice on safety, regardless of requirements - the requirements aren't going to help me bail out a flooding boat...

[ssullivan]

Tyrol... I hadn't been on this thread for a while and just wanted to give you a hearty "thumbs up." Good job getting those threaded intakes out. YIKES!

Of course all the advice above is correct (making sure to seal so no moisture can get into the hull laminates). But I think you're a long way toward having what was at first a scary project done. Installing the proper seacocks in a well-prepped hull is the easy part.