Through hull and valve questions

Ask a question...get an answer (or two).
Post Reply
User avatar
Rachel
Master of the Arcane
Posts: 3044
Joined: Tue Dec 07, 2004 7:59 pm

Through hull and valve questions

Post by Rachel »

My boat has seven through hulls, and one log propeller exit below the waterline. There's an assortment of gate valves and ball valves, but no true seacocks (photos below). Right now my boat is out on the hard, which would make it a great time to replace some of these, except it isn't...

There are a few reasons why I'm not just jumping in and replacing all of these. For one thing, I'm busy with the bilge, and for another it's cold outside and dark early, so not great weather for working on things or making fiberglass patches if I elimate some of them. I'd like to live with things for awhile in any case, so that I can make better decisions about which ones to replace with seacocks and which to eliminate.

Of course the boat has lived with many of these for 40 years, and if the PO still had the boat it would be launched next spring probably without a second thought about these. If I'd bought the boat in the water, I might not be starting this thread so soon. And it's not that the PO was terribly thoughtless: Many boats on the Great Lakes - with its fresh water and very short season - do still have gate valves. I think the editor of Good Old Boat even wrote an editorial defending them up to a point, if I remember correctly (he wasn't saying they are great, or anything anyone should install, but was responding to the idea that everyone on the Great Lakes should immediately schedule a panicked haul-out and change them).

On the other hand, I hate the though of dicey things below the waterline. That's something I really don't want to think about every time I come around the corner to my boat...

Here's a question: Since I have no immediate need to use some of these valves (and would just be keeping them closed), could I just take them out and put in new, bronze through hulls, tighten them down from inside with the nuts that come with them, and then cap them off somehow? Then if I decided to eliminate them later, no big loss, and if I decided to keep them, I could put seacocks on (wait, I'd have to remove them to screw them back into the seacock, right?).

I know this is totally subjective, and the prudent mariner would immediately change all of these for seacocks, but I'm just trying to strike a balance between the me that's screaming "Out! Out! Take them out and replace them with proper seacocks!" and the other me saying "Just launch the boat and stop camping in the boatyard. They've been like that for ages. You can haul later this year, when things are warmer and more relaxed." One note is that I would probably keep the portside cockpit drain valve closed unless I replace that clear hose.

And is that Sumlog exit okay? I guess they don't normally have any kind of seacock, do they?

Okay, you probably want to see what I'm talking about:

Image
Engine intake valve.


Image
Port-side cockpit drain gate valve. As you can sort of see, the icebox drain has been Teed into the line, with clear, "not for use below the water line" hose used above the tee. Oh, and how embarrassing, my wire-nuts are showing!



Image
Another view. Yeah, non-AWAB clamps and not always two, either (though maybe that's okay if they're good clamps?).



Image
Here's the starboard-side cockpit drain gate valve. Although these would be kind of hard to get to (but not impossible) with the engine there, at least there is plenty of room for hose (I believe) between the cockpit drains and the hull.



Image
This valve is capped off, but it's the former seawater intake for the galley sink, and it's in a locker under the sink (stbd). I now realize I forgot a couple of photos -- there is a larger gate valve (like the cockpit drain ones) for the sink drain. I'm not sure what these backing pads are made of. That brown stuff is hard, so I'm not sure if it's rotting backing pad, or some kind of resin leftover, or something even more frightening I haven't though of yet...


Image
This is the head intake valve. Although I realize from reading that there may not be many threads engaged (shudder), at least the top of this line is captured by the shelf the head sits on, so it can't be easily broken off.

Also, there is another large gate valve near this one (sorry, forgot photo) that is capped off like the one under the sink. It's the head discharge (the head is routed into a holding tank only, since the Great Lakes are a no-discharge zone).

--- Rachel
bcooke
Master of the Arcane
Posts: 2272
Joined: Sat Oct 04, 2003 10:55 pm
Boat Name: Jenny
Boat Type: 1966 Pearson Triton
Location: Rowley, MA
Contact:

Post by bcooke »

I guess I would be tempted to keep the valves shut and launch. Plan a haulout in the summer when the yard isn't too busy to remove the seacocks you don't need and fill the holes.

Any seacock locations you want to keep could be changed pretty easily now though. I think you could do them all in a day. I don't know how low a temperature 3M 5200/4200 can go but that is what I would use for bedding new seacocks.

That log fixture looks pretty odd but I really can't see it well enough to comment on. It looks like it is just stuck through a hole (crooked at that) with some goop to keep the water out.

-Britton
-Britton
Work is overrated.

Most everything you read on the Internet is wrong.

The Website
The Blog
User avatar
Peter
Boat Obsession Medal Finalist
Posts: 580
Joined: Mon Nov 15, 2004 11:23 pm
Boat Name: Pagan
Boat Type: Albin Ballad 30
Location: Pedder Bay (Victoria), BC, Canada
Contact:

Post by Peter »

Britton wrote:I don't know how low a temperature 3M 5200/4200 can go but that is what I would use for bedding new seacocks.
I used 3M Fast Cure 5200.
It tacks up nicely in about an hour and cures in about 24 hours.

The instructions say not to apply below 40 degrees F, which might be a tall order where you are, Rachel.
Peter
==================
Victoria BC Canada
Albin Ballad 30

http://www.mostlyaboutboats.ca
User avatar
Tim
Shipwright Extraordinaire
Posts: 5708
Joined: Tue Apr 01, 2003 6:39 pm
Boat Name: Glissando
Boat Type: Pearson Triton
Location: Whitefield, ME
Contact:

Re: Through hull and valve questions

Post by Tim »

Rachel wrote:My boat has seven through hulls, and one log propeller exit below the waterline. There's an assortment of gate valves and ball valves, but no true seacocks (photos below). Right now my boat is out on the hard, which would make it a great time to replace some of these, except it isn't...
Do your gate valves operate? The look to be in mostly good condition, and should be since they lived in fresh water. Just because the valves look good doesn't mean they are in proper operating condition, so you should test them not only for basic operation (i.e. turn the handle), but also ensure they close fully and don't leak. You'll need to close the valves in question and fill the hoses and then leave them for a day or two in order to monitor the watertight integrity of the closed valve.

As long as the valve bodies, related fittings, and through hulls are in good structural condition, and if you plan to leave certain valves open (such as your scuppers), then the ability to have a totally watertight seal, for the way you plan to use the boat in the near future, isn't necessarily paramount. You can live with them for now, in other words. Unless any of the valves are somehow substandard. (See my further comments towards the end.)

Looking though the photos again, however, I see a lot of pipe nipples in the mix. We've all determined that you can't find bronze pipe nipples, so those are probably brass. Brass doesn't belong in any potentially underwater connection, so while you may not need to replace your valves right now, those nipples probably have to go. And pretty soon, though as long as your valves work you can do it with the boat in the water if you want.
Rachel wrote: There are a few reasons why I'm not just jumping in and replacing all of these. For one thing, I'm busy with the bilge, and for another it's cold outside and dark early, so not great weather for working on things or making fiberglass patches if I eliminate some of them. I'd like to live with things for awhile in any case, so that I can make better decisions about which ones to replace with seacocks and which to eliminate.

Of course the boat has lived with many of these for 40 years, and if the PO still had the boat it would be launched next spring probably without a second thought about these. If I'd bought the boat in the water, I might not be starting this thread so soon. And it's not that the PO was terribly thoughtless: Many boats on the Great Lakes - with its fresh water and very short season - do still have gate valves. I think the editor of Good Old Boat even wrote an editorial defending them up to a point, if I remember correctly (he wasn't saying they are great, or anything anyone should install, but was responding to the idea that everyone on the Great Lakes should immediately schedule a panicked haul-out and change them).
There are a few reasons why gate valves have fallen out of favor.

First, and most importantly, it's very easy for the seal to become compromised because of the way the valve operates. Debris can get in there and prevent the valve from closing properly, or at all. Ball valves don't have this issue, which is why they gained popularity.

Next, gate valves are rarely flanged, and therefore the whole arrangement is less strong than a valve that incorporates a strong mounting flange (i.e. a true seacock). This can be an important issue, particularly if the valve becomes sticky and hard to operate, but again: it's not as if your boat will immediately blub-blub to the bottom if you launch her with these valves still in place.

Finally, and far less importantly, quarter-turn ball valves offer a clear and immediate visual indication of whether they're open or closed, whereas you can't tell with a gate valve. Also, the handles and stems become easily corroded and may become inoperable as a result. This is only an issue in salt water, really. And it won't happen overnight.

I wouldn't go so far as to defend gate valves and condone their continued use, and I believe that you should eventually replace them all, but a bit of common sense comes into play when determining the importance of their immediate replacement. I suspect that things are probably in good enough shape that you don't have to worry about it right this minute. Schedule it for your next haulout. If you don't get your boat in the water soon, she may not get in this year, the way these things compound and expand to use all and more available time. Do only what is absolutely required at this stage, and lacking evidence to the contrary, I don't think the through hulls are on that list right now--unless there is a true reason to replace any of them right now, such as substandard materials or clear signs of structural or other unsuitability. (Again: see my comment at the bottom of this response.)

Otherwise, I'd install your new garboard plug, clean the bilge, and launch.
Rachel wrote:Here's a question: Since I have no immediate need to use some of these valves (and would just be keeping them closed), could I just take them out and put in new, bronze through hulls, tighten them down from inside with the nuts that come with them, and then cap them off somehow?
Assuming the existing valves work and don't leak, as I discussed above, you're better off leaving things as is for now. I don't see any reason to replace the through hulls right now unless their condition truly calls for it--which it doesn't sound is the case, at least for most of your fittings. Again: schedule the replacement of all the valves and through hulls for a later date, even later this year, but there's no reason to breathlessly take care of it all now, unless you want to turn your boat into a torn-apart project for the whole summer.
Rachel wrote:...and the other me saying "Just launch the boat and stop camping in the boatyard. They've been like that for ages. You can haul later this year, when things are warmer and more relaxed."
Listen to this voice for now, but don't ignore the one telling you that something better is eventually called for.
Rachel wrote:One note is that I would probably keep the portside cockpit drain valve closed unless I replace that clear hose.
Good call.
Rachel wrote:And is that Sumlog exit okay? I guess they don't normally have any kind of seacock, do they?
No, they don't have a seacock. Leave this alone until the time comes (if the time comes) when you want to remove it and patch the hole.

Was this shown in one of the pictures? I didn't see it.
Rachel wrote:Image
Another view. Yeah, non-AWAB clamps and not always two, either (though maybe that's okay if they're good clamps?).
Double-clamping is a misnomer in many cases. Most hose barbs simply do not have sufficient room to allow for two clamps to seat properly on the barb without ending up too close to the end of the hose or the hose just past the barb. Older hose barbs and some straight nipple connections are often truly long enough to allow the use of two clamps, if desired.

The clamps need to be quality in any event, but a single hose clamp is most usually better than two on modern fittings.

Those are pretty cheesy looking hose clamps, too, so I'd suggest replacing them on all your underwater hoses now.

Note that the only hoses for which double clamps are indicated, whether by US Code or CFR (therefore required) or ABYC (therefore suggested, if not strictly required by any enforceable law) are the fuel fill hose at both ends, and the engine exhaust hose at all connections. Nowhere does it even mention double clamps for other hoses.

Many hoses are ruined by inappropriate clamping. Following proper clamping procedures and using high quality clamps will ensure long-lived safety.
  • 1. Clamps too close to the end of the hose can cause damage to the end of the hose, particularly if over-tightened. THe hose end may splay out and crack, or form other damage.

    2. Clamps too close to the hidden end of the barb inside the hose can actually start to force the hose off the barb--again, particularly if over-tightened, where the force can cinch the hose together and actuall start squeezing it off the barb.

    3. The typical perforated hose clamps bite into the hose and damage the outer casing. In addition, the sharp edges of most hose clamps cause similar damage.

    4. Tight enough is tight enough. You don't need to crank them down to within an inch of their lives. When they are secure and don't leak, it's enough.

    5. Inexpensive clamps have non-stainless adjustment screws that often corrode and fall out. Obviously this is a bad thing.

    6. A single quality clamp, with a solid, rolled-edge band and made of all 316 stainless (yes, AWAB), secured roughly in the center of the hose barb, is the most secure way to go about it.
Rachel wrote:Image
This valve is capped off, but it's the former seawater intake for the galley sink, and it's in a locker under the sink (stbd).
What is that capped with? Whatever it is, remove that cap and replace it with a bronze one. You don't want obviously mixed metals like that in a saltwater boat--never mind that the cap looks like some sort of zinc-plated thing that is utterly inappropriate here.
Rachel wrote:Image
This is the head intake valve. Although I realize from reading that there may not be many threads engaged (shudder), at least the top of this line is captured by the shelf the head sits on, so it can't be easily broken off.
That actually looks fairly well threaded to me. There are virtually always threads showing when a fitting is tightly secured, though you are right that incompatible threads on pipe fittings lead to a lot of improperly threaded installations.

I don't like this valve, though. It looks like a boiler-type valve, which may be brass, and the handle doesn't look stainless to me either--it looks zinc-plated. Of the pictures you've shown us, this particular valve looks like it might be worth replacing now. But read on.

Here's a final question. If you launch now, when would you realistically be able or willing to haul again to address any of these issues?

I truly think you'll be better off to get your boat in the water sooner than later and make her the true liveaboard that you want and need. Breathe a little, clean things up, and make her home--and relax. You could leave every issue you've pointed out for a later date, but some of them shouldn't be left for too long, particularly given the fact that it is looking increasingly as if your boat's former owner or caretakers used fittings that might be suitable in the lakes, but not so much in the ocean.

That said, several months or more in the water isn't going to make these things fall apart. Maybe late summer or early fall would be a good time for a haulout dedicated to replacing these fittings to suit your desires. But I think that trying to cram this all in now, when what you really need (and a main reason for buying the boat) is a place to call home. While I am in no way condoning nor supporting installations that aren't all they should be, sometimes a little sense and judgement is called for, and prioritizing the bigger picture.
---------------------------------------------------
Forum Founder--No Longer Participating
User avatar
Ceasar Choppy
Boat Obsession Medal Finalist
Posts: 622
Joined: Thu Mar 09, 2006 11:05 am
Location: Port Starboard, MD

Post by Ceasar Choppy »

Peter wrote:
Britton wrote:I don't know how low a temperature 3M 5200/4200 can go but that is what I would use for bedding new seacocks.
I used 3M Fast Cure 5200.
It tacks up nicely in about an hour and cures in about 24 hours.

The instructions say not to apply below 40 degrees F, which might be a tall order where you are, Rachel.
After having cursed many a PO for bedding thruhulls and seacocks in 5200 as I tried to remove them to replace, I would implore anyone not to do this. The strength of 5200 here is overkill if the seacocks are installed correctly. 101 works just as well for this application. Not only is 5200 very difficult to remove, sometimes part of the boat goes with it.

If you plan on keeping your boat for 10 years and it comes time to replace thruhulls, you will appreciate how much easier they will be to remove. Sorry if I sound preachy, but I removed 9 thruhulls last year and my arms still ache thinking about it.
Figment
Damned Because It's All Connected
Posts: 2847
Joined: Tue Apr 08, 2003 9:32 am
Boat Name: Triton
Boat Type: Grand Banks 42
Location: L.I. Sound

Post by Figment »

I don't like this valve, though. It looks like a boiler-type valve, which may be brass, and the handle doesn't look stainless to me either--it looks zinc-plated. Of the pictures you've shown us, this particular valve looks like it might be worth replacing now. But read on.
The whole impact-resistance thing is important, but this is my personal #1 beef with the use of non-flanged valves: It's all too common for them to have been procured via non-marine sources, and this is perhaps the ONE case where that really counts for something.
Even the HIGHEST quality valve carried by your local hardware or plumbing supply house uses a combination of dissimilar metals. In 99% of all industrial uses that's perfectly fine, but somewhere in that assembly there is something that will not survive a saltwater environment for long. Even valves with "bronze" bodies (notice that they never specify WHICH bronze they use) and "stainless" ball can have brass or mild-steel or zinc components elsewhere in the mechanism.

OK, enough of my pet peeve.

I'm kinda on Britton's mindset with this one. Cost aside, replacement of all of these valves with proper seacocks really should not be a terribly time-consuming operation. You're not cutting any new holes, not trying to fair anything in, most have what appear to be adequate backing plates, it really is a straightforward issue of replacement. I wouldn't even worry about the curing temperature of the sealant. So what if you launch with partially-cured sealant?

Just one guy's opinion, of course. I doubt you'll go far wrong with either path.
User avatar
catamount
Candidate for Boat-Obsession Medal
Posts: 378
Joined: Sun Jun 19, 2005 7:30 am
Boat Name: GREYHAWK
Boat Type: Peterson 34
Location: Boothbay Harbor, ME
Contact:

Post by catamount »

Ceasar Choppy wrote:After having cursed many a PO for bedding thruhulls and seacocks in 5200 as I tried to remove them to replace, I would implore anyone not to do this. The strength of 5200 here is overkill if the seacocks are installed correctly. 101 works just as well for this application. Not only is 5200 very difficult to remove, sometimes part of the boat goes with it.

If you plan on keeping your boat for 10 years and it comes time to replace thruhulls, you will appreciate how much easier they will be to remove. Sorry if I sound preachy, but I removed 9 thruhulls last year and my arms still ache thinking about it.
How often does one have to replace thru-hulls? and Why?

On my boat, I've pulled most of my thru-hulls only because whatever bedding compound was used 25 years ago has finally broken down and some of them were beginning to weep. I plan to re-use the existing (bronze) thru-hulls. They shined up well, and are still bronzy and not pinkish, so...

That said I will probably use polysulfide rather than 5200 when I put them back in, just because you never know... What would be the arguments in favor of using 5200 for this?

My curiousity is aroused as to just what are the appropriate uses for 5200. About the only place I can really see using it is in the keel-to-hull joint! (Oh, and for sail repairs) But I'm open to suggestions...

Regards,
Tim Allen -- 1980 Peterson 34 GREYHAWK
Harborfields Housekeeping Cottages, West Boothbay Harbor, Maine
Sailors for the Sea, a new voice for ocean conservation
Quetzalsailor
Master of the Arcane
Posts: 1100
Joined: Fri Aug 26, 2005 9:53 am
Boat Name: Quetzal
Boat Type: LeComte North East 38
Location: Philadelphia, PA

Post by Quetzalsailor »

I've heard that some boats have gate valves for seacocks. I've heard of through hulls breaking off when you operate the valve handle. I've heard of the wood backing blocks rotting out and leaving the through hull or seacock with nothing to keep it from tipping as you crank on the handle.

I would not panic about this stuff; I would simply fix each and every one of these below-waterline issues, the plumbing valves, the wood backup blocks, the non-bolted seacocks, the wrong fitting type, the wrong hose clamp, the wrong hose, etc., in accordance with ABYC practice.

Decide which seacocks you need, which you might wish to plug forever or move; prioritize the ones that look the nastiest or prevent you from doing something else, or are vulnerable to damage. Pick two, three, or four each season and make them right.

Our 37 year old boat had 6 seacocks and 2 transducer mountings, and a mystery threaded thing that looked like a through hull filled with caulk. Three seacocks were original. Two of them were unoperable. One, newer seacock was mounted on the throughull and the backing block was a little soft. The transducers are quite new. The mystery turned out to be a defunct depthsounder transducer. We'll start our third full season this spring. Last spring I replaced three seacocks and through hulls, added one, moved one, filled two old holes and reshaped one. Of the three I have yet to do, one's easy and the two in the head are gonna' be awful. However, the head valves are mounted up on the stem of the through hull and I dread their breaking off as I operate 'em.

I used a Marelon seacock for the cockpit drain because of the geometry of the drains. I used bronze for the other three that I did last year, complete with fiberglass backer blocks and bronze bolts. I replaced all the associated hoses and clamps.
feetup
Almost a Finish Carpenter
Posts: 99
Joined: Tue Jan 16, 2007 11:35 am
Location: Ladysmith, Vancouver Island

Pipe threads in fittings

Post by feetup »

Just for general information, the standard that the American Society of Mechanical Engineers uses in the construction and operation of pressure vessels among other things states that the minimum number of threads that should be engaged on a NPT joint should be as follows...

1/2" to 3/4" =6 threads engaged.
1", 1 1/4" and 1 1/2" = 7 threads engaged
2" , 2 1/2" and 3" = 8 threads engaged

It goes up to 12" but I would be surprised if anyone had an 8" through hull.
These specs are for pressure fittings, but would be a very good rule of thumb for something like a boat that you really, really don't want to have a threaded joint failure below the waterline.

FWIW

Feetup.
bcooke
Master of the Arcane
Posts: 2272
Joined: Sat Oct 04, 2003 10:55 pm
Boat Name: Jenny
Boat Type: 1966 Pearson Triton
Location: Rowley, MA
Contact:

Post by bcooke »

Good info on the thread engagement but ...

Maybe I am showing my nerdy colors here but seacocks don't use NPT threads as far as I know. NPT (national pipe thread) are the tapered threads that jam together creating a tight leakproof seal. My seacocks (Forespar Marelon) use a straight thread.

I am also expecting my seacocks to last for another 40-50 years. With proper maintenance I think their lifespan could be indefinite. I don't plan on ever removing the seacocks and if lightning strikes and I do want to remove a seacock well then that's why God invented disc grinders.

The proper material for bedding seacocks is one of those topics that keep coming up here on the forum. Everyone has their reasons and I think in the final analysis, just about anything works so go with what makes you comfortable.

-Britton
-Britton
Work is overrated.

Most everything you read on the Internet is wrong.

The Website
The Blog
bcooke
Master of the Arcane
Posts: 2272
Joined: Sat Oct 04, 2003 10:55 pm
Boat Name: Jenny
Boat Type: 1966 Pearson Triton
Location: Rowley, MA
Contact:

Post by bcooke »

Good info on the thread engagement but ...
It was late. You were specifically directing your response to the threads on those pipe fittings in the photo weren't you? Oops, my bad.

-Britton
-Britton
Work is overrated.

Most everything you read on the Internet is wrong.

The Website
The Blog
User avatar
Tim
Shipwright Extraordinaire
Posts: 5708
Joined: Tue Apr 01, 2003 6:39 pm
Boat Name: Glissando
Boat Type: Pearson Triton
Location: Whitefield, ME
Contact:

Post by Tim »

bcooke wrote:Good info on the thread engagement but ...

Maybe I am showing my nerdy colors here but seacocks don't use NPT threads as far as I know. NPT (national pipe thread) are the tapered threads that jam together creating a tight leakproof seal. My seacocks (Forespar Marelon) use a straight thread.
The through hull fittings, which thread into the bottom of the seacock, use straight threads (untapered, or so-called "iron pipe thread" (yes, even if it's not iron pipe)), but the tailpieces that you screw into the top of the seacock inside the boat use tapered (NPT) threads so that they form that all-important tight jamming seal. There are different threads on each side of the seacock fitting--straight female threads on the bottom (hull) side, and tapered female threads on the top side. This is always important to remember, and it's critical to use the proper male threads when attaching nipples or barbed tailpieces to the inside of your flanged seacocks.

Straight threads are needed on the through hull because the fitting must be able to thread completely into the seacock, or however far it can to tighten against the hull. Tapered threads can't be bottomed out, and only thread a specific amount, which is why they can't be used on the through hull side of the seacock.

Most straight ball valves, such as those often seen masquerading as "seaccocks", have tapered threads, which is why they don't thread properly directly onto the inside of a threaded through hull fitting.

The various pipe threads can be extremely confusing, even for people who should be in the know (like welding shops, right Britton?).
---------------------------------------------------
Forum Founder--No Longer Participating
bcooke
Master of the Arcane
Posts: 2272
Joined: Sat Oct 04, 2003 10:55 pm
Boat Name: Jenny
Boat Type: 1966 Pearson Triton
Location: Rowley, MA
Contact:

Post by bcooke »

Very confusing. And when the 'professional' says there is only one kind of pipe thread and that is what he used it gets pretty frustrating trying to sort it out too.
-Britton
Work is overrated.

Most everything you read on the Internet is wrong.

The Website
The Blog
User avatar
Ceasar Choppy
Boat Obsession Medal Finalist
Posts: 622
Joined: Thu Mar 09, 2006 11:05 am
Location: Port Starboard, MD

Post by Ceasar Choppy »

catamount wrote:
Ceasar Choppy wrote:After having cursed many a PO for bedding thruhulls and seacocks in 5200 as I tried to remove them to replace, I would implore anyone not to do this. The strength of 5200 here is overkill if the seacocks are installed correctly. 101 works just as well for this application. Not only is 5200 very difficult to remove, sometimes part of the boat goes with it.

If you plan on keeping your boat for 10 years and it comes time to replace thruhulls, you will appreciate how much easier they will be to remove. Sorry if I sound preachy, but I removed 9 thruhulls last year and my arms still ache thinking about it.
How often does one have to replace thru-hulls? and Why?

On my boat, I've pulled most of my thru-hulls only because whatever bedding compound was used 25 years ago has finally broken down and some of them were beginning to weep. I plan to re-use the existing (bronze) thru-hulls. They shined up well, and are still bronzy and not pinkish, so...
If your THs shine up without the pink, that is great. It is time to change them when they turn pink. Unfortunately, they tend to turn pink from the inside out so sometimes you cannot tell. All depends on where you sail and how much electricty is floating around in your marina!
catamount wrote: My curiousity is aroused as to just what are the appropriate uses for 5200. About the only place I can really see using it is in the keel-to-hull joint! (Oh, and for sail repairs) But I'm open to suggestions...

Regards,
Good question! I only use it to mount stuff to bulkheads I don't want to put a screw or bolt through! LOL.
User avatar
catamount
Candidate for Boat-Obsession Medal
Posts: 378
Joined: Sun Jun 19, 2005 7:30 am
Boat Name: GREYHAWK
Boat Type: Peterson 34
Location: Boothbay Harbor, ME
Contact:

Post by catamount »

Ceasar Choppy wrote:
catamount wrote: My curiousity is aroused as to just what are the appropriate uses for 5200. About the only place I can really see using it is in the keel-to-hull joint! (Oh, and for sail repairs) But I'm open to suggestions...

Regards,
Good question! I only use it to mount stuff to bulkheads I don't want to put a screw or bolt through! LOL.
It occurred to me that another good use for 5200 would be the deck-to-hull joint. :-)
Tim Allen -- 1980 Peterson 34 GREYHAWK
Harborfields Housekeeping Cottages, West Boothbay Harbor, Maine
Sailors for the Sea, a new voice for ocean conservation
User avatar
Rachel
Master of the Arcane
Posts: 3044
Joined: Tue Dec 07, 2004 7:59 pm

Post by Rachel »

While we're on the topic of through-hulls, a question popped into my head while I was driving along today:

From what I understand, you shape the hull side of a through hull backing pad to match any curvature of the hull that exists there. I can imagine doing that for a wooden backer, but I like the idea of using G10 or some similar fiberglass product, and they sound rather hard to work.

Does one customarily shape them? (And if so how.) Or... what about pushing one onto a pile of thickened epoxy in the designated spot, then letting it set up. If that's an option, would you want to use something to make it release from the hull so that it was molded to shape, but then removable before finally re-affixing it? Or?

Thanks,

Rachel
Figment
Damned Because It's All Connected
Posts: 2847
Joined: Tue Apr 08, 2003 9:32 am
Boat Name: Triton
Boat Type: Grand Banks 42
Location: L.I. Sound

Post by Figment »

Rachel wrote:what about pushing one onto a pile of thickened epoxy in the designated spot, then letting it set up.
Bingo.
Edit: within prudent limits, naturally. The curing process is exothermic after all.

(sometimes a little wood wedge is required in the pile of epoxy to ensure that it sits properly)
User avatar
catamount
Candidate for Boat-Obsession Medal
Posts: 378
Joined: Sun Jun 19, 2005 7:30 am
Boat Name: GREYHAWK
Boat Type: Peterson 34
Location: Boothbay Harbor, ME
Contact:

Post by catamount »

And no need to make it removable -- let the G10 backing plate become one with the hull
Tim Allen -- 1980 Peterson 34 GREYHAWK
Harborfields Housekeeping Cottages, West Boothbay Harbor, Maine
Sailors for the Sea, a new voice for ocean conservation
keelbolts
Skilled Systems Installer
Posts: 271
Joined: Mon Jun 12, 2006 12:20 pm
Location: Tidewater, VA

Post by keelbolts »

I never do anything on my boat without bearing in mind that, eventually, I'm going to have to do it again. The idea of glueing a seacock into a boat makes me uncomfortable.
Hirilondë
Master of the Arcane
Posts: 1317
Joined: Thu Dec 28, 2006 8:50 am
Boat Name: Hirilondë
Boat Type: 1967 Pearson Renegade
Location: Charlestown, RI

Post by Hirilondë »

keelbolts wrote:I never do anything on my boat without bearing in mind that, eventually, I'm going to have to do it again. The idea of glueing a seacock into a boat makes me uncomfortable.
Yup! There are so many ways to do something well that can come apart. And you never know when you may change your mind.
Dave Finnegan
builder of Spindrift 9N #521 'Wingë'
--------------------------------------------------------------------------------------------------------------------------------------------------------------------
Gresham’s Law of information: Bad information drives out good. No matter how long ago a correction for a particular error may have appeared in print or online, it never seems to catch up with the ever-widening distribution of the error.
Quetzalsailor
Master of the Arcane
Posts: 1100
Joined: Fri Aug 26, 2005 9:53 am
Boat Name: Quetzal
Boat Type: LeComte North East 38
Location: Philadelphia, PA

Post by Quetzalsailor »

Unless I missed something in one of the previous posts, you don't glue the through hull or the seacock in. You can glue the backing block in. If it's a fiberglass backing block, it's part of the boat. If it's a built-up area of fiberglass, it's part of the boat. The throughhull and the seacock need to be renewable. I counterbored my backer blocks and buried bronze nuts in there. Comes time to renew the seacock the bronze capscrews will come out.

It is wonderfully difficult to get some throughhulls out: some are gooped in with polyester filler, some glued in with 5200. If it's just the through hull that's stuck in place, you can make a puller with a bit of threaded rod, large washer, nuts, wood strongback and blocks. Of course, you must be sure that a nut isn't buried under some filler (imagine the installer who bedded the through hull, put a nut inside and glopped filler around it to bed the seacock...)

If the seacock is simply threaded onto the throughhull, even buried somewhat in filler, take the plug out and clamp or bolt a huge long lever to it. It's usually inconvenient to use a 5' lever but it worked for me.

If you can't succeed that way, an hour or so will suffice to grind the flange off from outside. Yes, you can grind even a recessed, flush flange off without damaging the fiberglass. Been there; all you are trying to do is cut the flange from the threaded stem; the remaining gnawed ring will pop out.

Bed the thoughhull in your favorite goo. Thread the seacock onto it using pipe dope.
keelbolts
Skilled Systems Installer
Posts: 271
Joined: Mon Jun 12, 2006 12:20 pm
Location: Tidewater, VA

Post by keelbolts »

I reread Rachel's post. She is talking about glueing the backing plate in - not to seacock. Duhhhhhhh. My bad.
Post Reply