Installing new head seacock/thru-hull

[Leo MacDonald CD30K]

Hi CD'ers,
I'm installing a holding tank pumpout capability to my CD30K. Every thing but the overboard seacock/thru-hull is in place. The right angle hose adapter, seacock and thru-hull have been purchased from Spartan. On drilling the hole through the hull I found the gap between the liner and the hull itself was approx. 1/4 in, a little more at the bottom than the top. My initial thought was to fill the gap area with GRP and mount the valve on the surface of the liner. However, I don't think the GPS packed into this small gap will be 100% complete. I now an considering cutting away sufficient liner to mount, and thus seal the thru-hull, directly on the hull. Note the hull is 1/2 in, thick and the liner is 3/16 in. thick. A third option would use the liner piece cutout as a backing plate with 5200 between it and the hull, between the thru-hull and the hull & between the seacock and the liner piece.
What say the collective wisdom ???
Leo MacDonald CD30K Heather Ann (on the hard - this being now GOOD due to a HOLE in hull - in Groton CT)



macdola@gwsmtp.nu.com

[Jeff Schmoyer]

Leo,

I'm going to vote strongly for cutting back the liner, NOT bonding liner to hull. I think it's going to be hard to get a strong bond between liner and hull because you don't have access to much surface area. This, plus I could easily see this bond receiving a lot of strain as the hull and liner flex in opposite ways in a seaway.

Previous owner on my CD27 installed same under the port settee. The liner was cutback in a nice neat circle about 8" in diameter (used a very large hole saw I guess). Unfortunately, they used a plumbing supply house 90 degree angle seacock and a smallish unsealed piece of plywood for a base. Wouldn't you know it- the setup leaks. So this winter, I have to tackle this. I only hope they didn't bed everything w/ 5200!

Jeff



Jeff.Schmoyer@IFF.com

[Tom]

Hi CD'ers,
I'm installing a holding tank pumpout capability to my CD30K. Every thing but the overboard seacock/thru-hull is in place. The right angle hose adapter, seacock and thru-hull have been purchased from Spartan. On drilling the hole through the hull I found the gap between the liner and the hull itself was approx. 1/4 in, a little more at the bottom than the top. My initial thought was to fill the gap area with GRP and mount the valve on the surface of the liner. However, I don't think the GPS packed into this small gap will be 100% complete. I now an considering cutting away sufficient liner to mount, and thus seal the thru-hull, directly on the hull. Note the hull is 1/2 in, thick and the liner is 3/16 in. thick. A third option would use the liner piece cutout as a backing plate with 5200 between it and the hull, between the thru-hull and the hull & between the seacock and the liner piece.
What say the collective wisdom ???
Leo MacDonald CD30K Heather Ann (on the hard - this being now GOOD due to a HOLE in hull - in Groton CT)

I second Jeff's opinion. I had one installed by a yard. They cut back the liner epoxied a teak backing plate to the hull and then drilled through. The wood may not be necessary but I'd go to the hull. Notice there are no other through hulls that go thrugh the liner.



TomCambria@mindspring.com

[Bill Goldsmith]

I'm going to second Jeff's vote about cutting away the liner. The most important thing to be sure of is adequate backing on the inside to absorb the flexing of the opening and closing force of the seacock. AYBC standards actually require the backing to enable the seacock to withstand someone standing on the installed seacock at a 45 degree angle. I doubt that filler of any kind between the liner and the hull will give you that kind of certainty. I would cut away enough liner to allow a decent size chunk of wood to be bonded to the hull where the hole is, perhaps with 5200, or epoxy. Do not, however, bond the through-hull to the hull with 5200 or epoxy. You may wish to remove that through-hull some day. There are better underwater bedding compounds for that. There's a pretty good diagram of a professional installation in Nigel Calder's Boatowner's Mechanical and Electrical Manual.

Good luck and hope for an early Spring!

Bill Goldsmith
cd27 #172
Second Chance
Croton-on-Hudson, NY

Hi CD'ers,
I'm installing a holding tank pumpout capability to my CD30K. Every thing but the overboard seacock/thru-hull is in place. The right angle hose adapter, seacock and thru-hull have been purchased from Spartan. On drilling the hole through the hull I found the gap between the liner and the hull itself was approx. 1/4 in, a little more at the bottom than the top. My initial thought was to fill the gap area with GRP and mount the valve on the surface of the liner. However, I don't think the GPS packed into this small gap will be 100% complete. I now an considering cutting away sufficient liner to mount, and thus seal the thru-hull, directly on the hull. Note the hull is 1/2 in, thick and the liner is 3/16 in. thick. A third option would use the liner piece cutout as a backing plate with 5200 between it and the hull, between the thru-hull and the hull & between the seacock and the liner piece.
What say the collective wisdom ???
Leo MacDonald CD30K Heather Ann (on the hard - this being now GOOD due to a HOLE in hull - in Groton CT)

goldy@bestweb.net

[Olli Wendelin]

Leo,

I recommend cutting the liner oversize to allow seating the thru hull directly to the hull/ backing block. I have several thru hulls in my head and v-berth area which are done this way.

I have considered increasing the holding tank capacity and pump out capabilities on my CD30 ketch. My ship was origionally commissioned without any tank. The 3 gallon tank now installed is mostly for show. Could you e-mail me the details of you arrangement, maybe a photo?

Olli Wendelin
BLUE MOON
Charleston, SC



wendelin@spawar.navy.mil

[Leo MacDonald CD30K]

Olli,
The holding tank exactly conforms to the VERY irregular puka at the forward end of the space below the V-berth. Capacity is 24 gal. and MFG is Kracor (?) with inspection port approx. top center. The pumpout fitting exits top fwd with internal plastic (?) pipe running at a diagonal to the aft lower area. Most likely a liner / tank design coordination. Kracor may be able to supply it, they are still in the tank business. The V-berth is "the shop" with boards still in place. If they come out I'll take pics and dimensions and snail mail them.
You still in the water??
Thanks for your info.
Leo, CD30K Heather Ann



macdola@gwsmtp.nu.com

[jim stull]

Hi CD'ers,
I'm installing a holding tank pumpout capability to my CD30K. Every thing but the overboard seacock/thru-hull is in place. The right angle hose adapter, seacock and thru-hull have been purchased from Spartan. On drilling the hole through the hull I found the gap between the liner and the hull itself was approx. 1/4 in, a little more at the bottom than the top. My initial thought was to fill the gap area with GRP and mount the valve on the surface of the liner. However, I don't think the GPS packed into this small gap will be 100% complete. I now an considering cutting away sufficient liner to mount, and thus seal the thru-hull, directly on the hull. Note the hull is 1/2 in, thick and the liner is 3/16 in. thick. A third option would use the liner piece cutout as a backing plate with 5200 between it and the hull, between the thru-hull and the hull & between the seacock and the liner piece.
What say the collective wisdom ???
Leo MacDonald CD30K Heather Ann (on the hard - this being now GOOD due to a HOLE in hull - in Groton CT)

Hi Leo
I replaced all the old gate valves and added new valves for a new 13 gal holding tank. As previously mentioned the valves need to be mounted very solidly to an epoxy bonded and sealed wood plate to the hull. Then the valve is solidly bolted thru the backup plate to the hull. If it was bonded thru the liner any possible leak in the setup, for any reason, would be almost impossible to detect, as it could migrate between the liner and the hull and then show up in the bilge. Drive you nuts trying to locate it.
Get one of the good reference books and study the set-up. This is serious business!
BTW: One problem I had with several of the new valves was getting the bolts to line up corectly. It was difficult to get a clear shot with a drill and any misalignment will cause problems getting the bolts thru the holes in the valve OR the heads of the bolts will be cockeyed when you try to pull them up tight. I ended up buying a right angle drill to finish the job. However you probably have more working room than I did on my CD25.
Jim



jtstull@icubed.com

[Leo MacDonald CD30K]

Hi guys,
Thanks much for the response. Given I now plan to cut the liner away AND use a backing 'plate', what is the preferred method/tool to cut the liner without damaging the hull proper?
Leo



macdola@gwsmtp.nu.com

[Tom]

Hi guys,
Thanks much for the response. Given I now plan to cut the liner away AND use a backing 'plate', what is the preferred method/tool to cut the liner without damaging the hull proper?
Leo

Isn't it great how you get the answers immediately on this BB! One way to do it that is real clean is to use the largest hole saw you can get. Leaves a nice round hole. You can turn it by hand or with a wrench if you don't have a power drill large enough or there isn't room to get a drill in.



TomCambria@mindspring.com

[jim stull]

Hi guys,
Thanks much for the response. Given I now plan to cut the liner away AND use a backing 'plate', what is the preferred method/tool to cut the liner without damaging the hull proper?
Leo

Hi Leo
As Tom says a hole saw does a perfect job. If the hole thru the hull has already been cut (leaving no purchase for the pilot drill) or if the hole size is very large I have had good success using a router with a straight cutting bit. "Sneak" up on the proper depth, (the thickness of the liner), by lowering the bit in small increments. A liminate trimer is ideal but any small router should work if space is available. A bit of practice would be in order on some scrap to get the feel of the operation. Of course this operation is VERY dirty so eye protection and dust mask will be necessary! In putting in the new portlites into my boat, I had to cutaway the liner around each old window to have access to the hull. This was the best system that I found. If you want to take the time to make a "perfect" opening a scrap wood pattern can be made and a pattern bit used to trace around it.
Jim



jtstull@icubed.com

[Leo MacDonald CD30K]

Thank you all,
All my thoughts were hashed out in the precieding messages and I thank you.
So, the plan is to 1) cut out a section of the liner (most likly w/ holesaw), 2) adhere a backing plate to the hull, 3) install the thru-hull / seacock, 4) pump the xxxx out of the holding tank and go on to the next project.
When this is complete I'll post the trials and tribulations story. Thanks again guys.
This b/board is a great resource. Thank you Walt.
Leo MacDonald, CD30K #57, Heather Ann



macdola@gwsmtp.nu.com

[Scott]

The router can do the job but you may not have enough room for that if you are working where I think you are. Another option is a Dremel tool with a router-like head. This thing is only about 2 inches in diameter and can get into much tighter spaces. With either router approach, recommend you use a jig or similar guide rather than try to "free-hand" it.



RitcheyVS@aol.com