Strange old thru-hulls

[tyrol]

Here's photos of a couple of my thru-hulls. I know I at least need to put proper seacocks on, and potentially replace the thru-hulls as well. But how?

Some of the "pipes" on the inside are fibreglass, but some are metal. They seem to be glassed right into the hull and there's no flange on the outside, just a hole, leading me to believe that maybe there's a flange (on the metal ones anyway) sandwiched into the hull itself? Can't just hole saw it out in that case without making a giant hole... The hull is solid glass about 1/4" thick.

One of the metal pipes has no thread or barb so I can't put a seacock on it regardless.

Advice??
Thanks,
Ty

[Joli]

Use an angle grinder and whack em off. Then install a proper seacock.

http://www.boatus.com/boattech/casey...lseacock_B.gif



Oh, and when you install the new seacocks make sure to work them regularly.

[tyrol]

Hmm, good idea... The new thru-hull would have to fit within the old hole then though, making it quite a bit smaller, wouldn't it? Unless I can somehow drill out the old piece to the right diameter. And I'm worried about damaging the hull if I attempt that? The first picture, no prob, but two and three where it's metal?

[ssullivan]

Joli has the only solution. Those odd seacocks need to be cut right out. If anything, cutting them out will give you a hole larger than the current hole, allowing you to put a larger seacock in if you are worried about water volume.

Just check into the required hole sizes for various seacocks and make sure there is one that will cover you if you cut a hole in the hull around these old non-closeable seacocks. Once the old one is out, it will be an easy job - just like installing a seacock on a new boat.

[tyrol]

All righty, will do. I'll let you know how it goes. Thanks Joli and Sean.

[hellosailor]

Tyrol, there's through-hulls in the proper and traditional sense, and seacocks, and somewhere in between every type of plumber's nightmare. But *almost* all the time, even if there's nothing showing outside the hull, someone has installed some type of flush fitting that does "mushroom" outside the hull so it isn't just a pipe running into a hole. Joli's line art shows a through hull plus a ball valve, which is often considered "improper" but is a very commonly accepted installation nonetheless. I wouldn't be concerned about either way, nor about the plastic-vs-metal issues.

"Doing it right" would mean exploring each of the suspect fittings, probably taking a dremel or other small tool and probing around the fitting to find out the extent of it, and then removing and replacing the whole thing completely--if you wanted to replace it. That can be a lot of work, and "scary" to a lot of boat owners because it means holes in the boat. If you look around, you'll find plenty of articles or sites to show you how to properly install a fitting, how/when to use a backing plate, how to seal a hole in the hull...It's really not a hard job, just scary until you learn how easy it is to do.

Metal means bronze, in theory. Except a lot of the best "marine bronze" fittings also technically qualify as brass, and some makers won't even tell you what alloy they use, they consider it a trade secret. Of course any metal alloy is susceptible to galvanic issues, so when someone tells you plastic can crack or melt...Sure it can, but it never suffers galvanic problems. Different, not better or worse.

More important is that each fitting is robust, secure, properly clamped and in working order. If there's any way that something big and heavy (or a foot) can impact the tube and break it...that needs work. But from what I see, the main issue you might have is that there are no backing plates, so an impact on the tubes could shear them, or break the fitting free. That can be repaired in place, by adding plates around them, and building up the fiberglass around them to brace the fittings better to the hull. Some cleanup with a wire wheel, some extra layup with epoxy and glass and filler to beef them up...I can't see any real reason to rip 'em all out or cut them off, unless you're planning a major overhaul on the haul and don't mind spending a lot of money on it. Or really really bullet-proofing for a globe hop. Good fittings won't be cheap. The ones you have, with a little work, can be made good enough.

And then, of course, you DO have damage control plugs, one sized to each fitting, and tied to it with a lanyard, as per the ORC regulations, right? Somehow it just seems there's always something higher on the ToDo list, but at least this year I drilled holes and put strings in 'em all. Maybe in the spring I'll tie them to the fittings, instead of letting them hang in the galley.<G>

[tyrol]

Hey Hellosailor,

Kiwi's out of the water now, so I want to take care of things "properly" - plus I need to make sure things are up to spec for my insurance. Not to mention that I won't feel comfortable without seacocks. That said I don't think I can get new seacocks to attach to these thru-hulls, so I guess I need to remove them and thus my problem:

I think these things are the originals from the 60's and so don't know how they're made. I don't think the pipe just runs into the hole, but it doesn't have a mushroom on the outside which is my concern - I think the mushroom might be sandwiched between layers of the hull? And it will be easy enough to grind off the pipe, but I'll also need to enlarge the hole for the new thru-hull and is that going to mean using a holesaw through a fibreglass and metal layer? I'm a bit worried that could get a bit messy...

It's not that I need a bigger hole, it's that the existing pipe uses up some of the hole if I just whack the protruding end off.

Know what I mean?

[hellosailor]

Tyrol-
The "flush" type fittings are shaped like a big flush-driven screw head, a "Y" profile with the top of the "Y" spreading out and being set into the hull. WIth a hull only 1/4" thick (!) that would be unlikely. A "mushroom" head is more conventional, and racers often fair that in by adding fairing OUTSIDE the hull to smooth it up to the edge of the mushroom rim.
But if you've just got "stuck a pipe in it"....yeah, I could see that being a concern. "it's that the existing pipe uses up some of the hole " Even then, you'd want to clean out all the old pipe because it is of unknown reliability. "HUll archaeology" time, huh?<G>

[tyrol]

Yeah, I guess it's time to do some exploring...

I was going to ask about the hull thickness too, now that you've noticed it... The deck is balsa cored, but from what I can tell (looking at the hole where I did remove a thru-hull), the hull is just solid glass and seems to be about 1/4" thick. Is that abnormal??? I know these were more racer than cruiser when they were built...

[Boracay]

Your boat is not sinking (out of the water) so my suggestions are ....
Don't touch the seacocks/standpipes etc.
Do a survey of your boat with particular empasis on the plumbing. From the photos it looks like other repairs/rewiring etc may be in order.
Now decide where the seacocks should be. Imagine them in those positions. It could be that they are already in the right positions but if as it is an old boat chances are they are not.
It seems to be common practice for cockpit drains to be large pipes and sometimes these are (in steel boats anyway) welded to the hull and cockpit with no seacock.
While you are doing this think about things like raw water strainers etc.(is a new engine in your future?)
If the pipes are solid fibreglass of a suitable thickness and act as standpipes to a suitable distance above the waterline it may be possible to leave them in place.
At this stage it may be possible to reduce the number of opening in your hull.
Now consider the difficulty of blanking off the water inlets that are not needed and reinforcing the hull in those areas.
Now consider placing all seacocks in the correct positions using proper installation methods.
If you really are unsure about the best way to proceed I would stronly recommend doing a deal with an experienced surveyor. It might be a couple of hundred bucks well spent.
Carpenters are supposed to measure twice and cut once. I find it wise to measure ten times and then to think about it.

[hellosailor]

Tyrol, what's normal or abnormal about any boat?<G> 1/4" of fiberglass apparently has worked, it probably gets thicker further down.

[Steve Rust]

If you find out that you end up with holes to large for seacocks when you remove the standoffs how about cutting them off but leave a inch or two protruding inside the hull. With a rasp clean out and rough up the inside and fill them with thickened epoxy paste, maybe add some chopped up glass fibers too. Add several of layers of cloth overlapping the hole on the outside. For good measure add a nice fillet of thickened epoxy around the nub on the inside of the hull. Drill new holes of the proper size where needed.

[mudnut]

Try and ask the PO whats gone on.The pics look like they have been "Glassed in".If ya carn't get hold of the PO,try cutting the "Glassed in bits"away down to the thru hull fittings.IMHO I think those fittings look like they need replacing anyway.Mudnut.

[David_Old_Jersey]

Hopefully the hull is solid fibreglass (and not cored like the deck).

I would be tempted to cut off the existing fittings and repair the holes, and then cut new ones.

Possibly this will make the job easier overall, but it would also give you a chance to relocate any for better access or even reduce the number of holes required...........if your Head is plumbed in you may want to make sure that the inlet and outlets are sufficiently apart to ensure that you do not pump in part of what has been pumped out!

BTW I would also double clip the hoses to the fittings.

[tyrol]

Hey y'all, thanks for all the great comments and advice.

I do feel uncomfortable with those old things so am happy to follow the general advice to completely replace them. I'm also in the midst of replacing almost all the electrical and most of the plumbing so like the idea of doing it all at once (I'm adding inverter and house bank and bigger alternator and pressure water and maybe hot water so you better expect a lot more questions!)

I was under the general impression it was best not to move thru-hulls around, but would much rather do so - the existing ones are inaccessible and difficult to maintain which kinda defeats half the purpose, right?

So, to repair the holes, per Steve's advice - whack them off to an inch (I guess for the epoxy to grab strongly?), rasp, fill, fillet the inside and epoxy, cloth and fair the outside... Sounds pretty doable. Any other warnings or advice on that?

And relocating them - other than David's advice to keep the head inlet and outlet a decent distance, any other input? I'll redo those, exhaust out, cooling water inlet, sink drains... Probably won't redo cockpit drains as they drain above the waterline in the very back and look pretty sturdy (there's no seacocks though)...

And if I go with flanged seacocks (like the Forespar), can I screw the flange to the backing block or should it be bolts through the hull and everything?

Thanks again!