Installing a seacock.

[Ed Schenck]

Finally going to do it, replace the 1/2" thru-hull and ball-valve with a 3/4" seacock on the head intake. I did this years ago on the engine cooling intake. My problem is that the bilge is very shallow up forward. And not very wide. I have the ball-valve on an elbow and a filter attached to that.

In the picture the thru-hull is bottomed out in the seacock. The gap is 1 and 9/16" inches. Our H37C hulls are very thick up there, maybe even an inch. But even with a 1/4" plywood spacer I will run out of threads.

I could use a 1/2" spacer but now I risk being too high for the elbow and the filter. So my plan is to cut the thru-hull shorter after I have fitted it to the boat. I can't see any drawbacks in shortening but thought I would ask.

By the way, if you Google "installing a seacock" the top hit is Don Casey on BoatUS. The second hit is much better and guess who? Yep, Maine Sail. And currently I have his "picture on the right", the "non-preferred" method. But he does not mention shortening the thru-hull.

 

[Maine Sail]

Ed,

Most ALL thru-hulls installed into proper seacocks are cut to length. Install a proper backing plate and the flanged seacock then thread in the thru-hull till it bottoms out. Measure the difference from the head to hull and remove that measurement + 1/8" to 1/4"..

I would highly suggest the use of a flanged adapter & UL Marine ball valve vs. a flanged seacock. Makes future changes of the valve easy & simple. I also much prefer the "dished" thru-hulls as opposed to the o-ring type groove. Much more sealing surface area..

This is a dished head thru-hull. It holds a LOT more sealant than the groove in your photo.

This is a Groco flanged adapter:

They allow for proper thread matching:

Here's a photo by a guy who actually made GOOD USE of the flanged adapter. He was able to stuff a plug into the thru-hull and replace the ball valve. A simple ten minute job. Without the flanged adapter this would have been a very, very expensive haul out and time consuming replacement. The flange and thru-hull, once installed can be considered nearly permanent and the valves replaced on an as needed basis simply and without a haul out and anywhere in the world..

Photo Courtesy Incredible Hull

By the way, if you Google "installing a seacock" the top hit is Don Casey on BoatUS. The second hit is much better and guess who? Yep, Maine Sail. And currently I have his "picture on the right", the "non-preferred" method. But he does not mention shortening the thru-hull.

The first photo makes mention of it;

"This item is called a thru-hull or sometimes a "mushroom head". They are straight threaded (NPS thread) so they can be cut to the correct length for your hulls thickness and then be threaded into a female straight threaded seacock or a flanged adapter. The one on the right has already been cut to length. Most all thru-hulls installed into proper seacocks will need to be cut to the proper length.":

 

[rhythmsurfer]

Looks great Ed.

 

[Ed Schenck]

Ah MaineSail, you always throw a wrench into my plans. Now I do understand and see the advantage. But do I really have to return my parts to Jamestown? Let me repeat what I think the advantages are. You like the mushroom head because you can get more sealant at the hole. And the flanged adapter allows replacing the valve in the water. Umm, not sure that sells it for me. You are right, reading it twice I did miss the part about shortening. Thanks for taking the time.

 

[Johnb]

What is the purpose of the stainless (?) screw in the flange? Grounding maybe.

 

[Maine Sail]

What is the purpose of the stainless (?) screw in the flange? Grounding maybe.

It's a bonding screw...

 

[Maine Sail]

Now I do understand and see the advantage. But do I really have to return my parts to Jamestown?

Not if you don't want to..

Let me repeat what I think the advantages are. You like the mushroom head because you can get more sealant at the hole.

Spot on. The only thru-hulls I have ever seen leak, other than ones that were a thru-hull with a valve threaded onto it, were they type you show with the very small sealant retention groove.

Properly installed into a stable, through bolted, flanged & proper seacock you'll likely never have an issue.

And the flanged adapter allows replacing the valve in the water.

No not entirely.

The Flanged adapter allows the replacement of a failed valve ANY TIME and with no disruption of the hull through bolts, bedding compound, no destruction of the thru-hull and a LOT less labor.

Our own boat had two Apollo seacocks installed in 2002/2003 when the engine was replaced. The yard did a terrible job, no backing plates, but the valves are good quality flanged Apollo/Conbraco valves. They are in need of replacement already!! They look fine on the outside but are no longer opening and closing as they should. (sorry for the grainy pic it's all I had)

This is going to require that I cut them out because they were sealed with 5200. Instead of being a 30 minute job, max, with no destruction of the thru-hulls it will be more like a full day job.

If they had been flanged adapters I'd simply thread on a new bronze UL Marine valve for a LOT less effort, time and $$$$.. Ball valves in the marine environment are not the longest lasting products. The old "real" seacocks like Spartan or Blakes were 100% 85-5-5-5 bronze and could be re-lapped and re-built and they can last 40+ years or more. Ball valves can't be re-built and I've never seen them last anywhere near as long as a tapered cone style....

With the availability of flanged adapters I feel it can be considered an unwise investment to not use them.. In fact they don't cost that much more, if any more.

Umm, not sure that sells it for me.

If you plan on keeping your boat, someday you'll be all dirty, sweaty, cussing an mussing and mumbling..."should have bought those flanged adapters..."...

SBO Chandlery 3/4" Valve = $20.28


I am SURE Dave or Phil would be GLAD to quote you on a flanged adapter and valve together!!


Jamestown Flanged Adapter 3/4" = $31.28

Jamestown Buck Algonquin Seacock = $44.29


The extra $8.98 seems a minor investment now considering the $$$ in the future when that permanent seacock fails to open or close..

You can also find the IBV-750 (valve)/$18.52 and IBVF-750/$25.04 (flange) for less money:

http://www.boatfix.com/shop3/store/viewItem.asp?idProduct=26652

http://www.boatfix.com/bykeywordnew2.asp?textfield=GRCIBVF750&texttype=2

At this store they come to less money than the seacock from Jamestown..

 

[Ed Schenck]

I really do appreciate your attention to detail MaineSail. Not sure about the math, I paid $59.37 total. But it is more about my laziness than money I suppose. I'll have to box and ship the parts back to Jamestown. Then I have to find a source for the thru-hull. I called Jamestown and they only know about the grooved flange.

 

[Jim Legere]

Ed, I changed out all my original H-37C gate valves for the Apollo flanged ball valve seacocks like you have several years ago. Where I could, I reused the orginal thru-hull fittings. I think they were Perko or Wilcox Crittenden. They all had the "O-ring groove" as opposed to the dish that Maine Sail likes. In the case of the head, I had to go up to 3/4" as 1/2" Apollo seacocks are not available (to my knowlledge). All thru-hulls had to be cut to fit. I also used epoxy painted marine ply as backing plates. I used 3M4200 for bedding and some kind of blue pipe goop I purchased at a plumbing supply store for the threads. I have not had any trouble with them whatsoever.

The 3/4" seacock for the head has a 90 deg. "street-ell" on top of it that goes to a tee that supplies water to the head and also supplies a galley salt water hand pump and, in the future, an anchor washdown pump. All this fits nicely below the cabin sole.

Jim

PS: I think it is more important to "stage" the tightening of bedded underwater fittings than to worry about the o-ring versus dish debate. I bedded my thruhulls in 4200 and partially tightend up using the backing plate and a nut (not the seacock). Left it for a day or two and then came back, gooped on the thread sealant inside and cranked the seacock on (while someone on the outside backed up with a thruhull wrench to prevent turning). This way I knew I had not "starved the joint". Thruhull wrenches are cheap and handy tools but a wrench handle or other flat bar the right size will also work.

 

[Maine Sail]

Jim

PS: I think it is more important to "stage" the tightening of bedded underwater fittings than to worry about the o-ring versus dish debate. I bedded my thruhulls in 4200 and partially tightend up using the backing plate and a nut (not the seacock). Left it for a day or two and then came back, gooped on the thread sealant inside and cranked the seacock on (while someone on the outside backed up with a thruhull wrench to prevent turning). This way I knew I had not "starved the joint". Thruhull wrenches are cheap and handy tools but a wrench handle or other flat bar the right size will also work.

Jim,

The install method for proper seacocks is to fully install and bed the seacock or flange to the inside of the hull then lather up the marine sealant to the thru-hull and drive the thru-hull home tightening it down, all the way, just once. That is why there is a groove or a dish to retain sealant. Both work, I just prefer the dish as there is more sealant surface area. As I mentioned with it going onto a proper through bolted seacock then there is no risk of it spinning and breaking the seal. I would not rush out to return that thru-hull if using it with a properly mounted seacock.

 

[Ed Schenck]

Thanks guys. I will take pictures. But it could be weeks before the weather is warm enough to do any epoxy work. We are just about to have another bout of rain and snow. The first task is to enlarge the hole to 3/4" and get it square to the mounting plate.

 

[Maine Sail]

The first task is to enlarge the hole to 3/4" and get it square to the mounting plate.

The easiest way I have found is to;

1- Use a fiberglass backer

2- Then thicken up some epoxy, VE resin or PE resin with some cabosil, milled fibers and chop.

3- Next wax the thru-hull and stick it into the hole from outside the hull and use a 2X4 propped against it to hold it into place.

4- Now slather your mixed thickened resin onto the hull and block.

5- Then use the thru-hull nut to draw the two together. Once tight fillet the edge around the backing plate with what squises out and clean up any excess resin. (If the hull has a deep curvature then you want to pre-shape the backing block to fit the hull better)

6- This makes for two parallel surfaces and a life long backing block that will never rot.

7-If you don't want to drill all the way through the hull for the seacock, some folks oddly enough don't like to do this, you can also use this method. Backing Blocks Alternate Method

 

[Ed Schenck]

MaineSail, your work and documentation astounds me. Do you ever sleep? And your workshop must be amazing. I used to have a drill press, lathes, good saws, etc. But not in a little condo(don't ever downsize, boat maybe but not home). I guess I can pay to have the work done because I really do not want to drill the three bolt holes. And I cannot even remember how I did the engine seacock.

 

[Mathurin]

Compas Marine (Maine Sail ) has three very nice articles about seacocks and thru hulls, anyway I think all the articles in there are worth a look !!!

http://www.pbase.com/mainecruising/boat_projects

 

[BStevenson]

As an addendum to the wealth of knowledge that MaineSail has provided, if the thru-hull is bedded with 5200, you can use heat to soften it up for removal. I had to replace a recalled seacock from Groco and their tech guy suggested this. He recommended a propane torch on the outside to get it uncomfortable to touch, but not crazy hot. I used a heat gun instead (cheap Harbor Freight model) since it was a gas powered power boat. It worked quite well.

The only problem I had was re-engaging the thru-hull threads on the new valve. The threads were not square when cut to length and the last thread rolled over. It wouldn't engage properly and I ended up with 5200 everywhere. That stuff does not clean up easily. After dressing the ends square, the re-assembly went easily. I like the idea of the flanged adapter.

Good luck.

 

[sandpiper10471]

5200 can be cleaned up when still wet with paint thinner (in Canada, Varsol) or acetone. I am sure there are other chemicals but these work for me. I prefer not to use acetone if I can help it due to fumes, quick flash-off etc. Always use a good mask and skin protection. Turpentine will likely work too. And of course there is that good old ubiquitous WD40. Lots of rags or paper towels and a handy bag for disposal. 5200 gets on EVERYTHING.

 

[guidera48]

I also replaced all my seacocks. I was removing the engine water intake thru hull when it broke. Not even half a turn and Pow! You can see in the first picture the threaded body of the thru hull still inside the elbow. I assume this was factory?
I replaced the 1/2 engine water and head supply with 3/4 units. I added another 3/4 for the A/C and galley pump. They have directional barbs so they can be directed towards the hose without much trouble. They are installed but not bedded yet. Waiting for another set of hands to help. I made a tool with ribar to tighten the mushroom head from the outside as tightly as possible when I replaced the galley and head thru hulls.

 

[Ed Schenck]

I recognize that shallow black bilge Jose. But not the location. Where are you working that the sole edges look like that? It looks like you cut something out. And yes, that gate valve on the elbow was original. Right again, scary!

 

[Stephen Trapani]

Apparently this is the currently-on-this-site-best-possible-method (I haven't been paying close attention) but the four holes in the hull per seacock gives me the heebee jeebees. I'm thinking the less holes below the waterline I have to keep track of, the better. Then, one of my seacock/valves is marelon, from back when that was the thing to do...

 

[Jim Legere]

Re: Installing a seacock

Apparently this is the currently-on-this-site-best-possible-method (I haven't been paying close attention) but the four holes in the hull per seacock gives me the heebee jeebees. I'm thinking the less holes below the waterline I have to keep track of, the better. Then, one of my seacock/valves is marelon, from back when that was the thing to do...

I have to agree with you about 3 extra holes per seacock. IMO, the through bolting is a throwback to the days of wooden boats. In a thick glass hull like the Cherubini Hunters, once a flanged seacock is threaded down tight on the appropriate through hull with a good backing plate (wood or glass) and lots of bedding compound (like 3M 4200 or LifeCaulk) thats the end of the story. A 10 lb sledge hammer would have a hard time breaking that valve off the through hull. I thought about drilling the bolt holes and passed.