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Catalina/Capri 25/250 Sailor's Forums

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Thru-hull Potential Disaster Avoided

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Deric
Captain

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USA
408 Posts

Initially Posted - 02/02/2008 : 16:47:58

Hello Folks,

I recently purchased '78 Cat 25 last September. I knew I had to replace the thru-hull and valves. I am so grateful for this website community for helping me understand why thru-hulls, seacocks, valves, are critical to the safety of a boat.

In the picture provided, The old plumbing is located on the right: the new plumbing on the left. You may note that the end of the pipe on the old thru-hull had been cut on an angle. This angle was made so that the contour of the pipe matched the curve of the hull - - Did Catalina produce the thru-hulls as such?

The new thru-hull has a mushroom rim, which strengthens the position of the thru-valve against the hull.

Notice that the new replacement also has a triangle base - - to fasten it to the hull securely. The old thru-hull had only been glassed to the hull.

Lastly, a handle on the new valve makes it easy for one to determine the status of the valve: Open or Closed. The old gate valve doesn't provide an indicator to determine the status its status, alas, "Round and round she goes, where she's at nobody knows."

Can you imagine the potential disaster the old thru-hull and valve could have caused?

My next action item is to get a block to place between the hull and the triangle base of the new replacement.

BTW - the two valves on the old plumbing were assigned to the sink and ice box respectively. I have decided not to use the ice box; hence, I only have one valve.

Edited by - on

ClamBeach
Master Marine Consultant

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3072 Posts

Response Posted - 02/02/2008 : 17:36:22

Yup, that's the old stock arrangement. A bronze pipe nipple glassed to the hull in a 'volcano' of fiberglass. Not the best setup, but I haven't heard of any that actually failed in service. Many (most?) of us have gone through the same replacement so we can sleep better at night.

Your new setup is plenty skookum.

Edited by - on

Dave Bristle
Master Marine Consultant

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Djibouti
10005 Posts

Response Posted - 02/02/2008 : 23:00:11

We call that old setup "to-hulls", since they don't really go through. As Clam indicates, I don't recall any reports of sinkings, but several reports of the old one practically falling out of the hull when the owner went to replace it.

Catalina switched around '83, I believe--at least by 1985--to flush-mount thru hulls (with a countersunk disk on the outside) and ball valves. What you've done is even a little more solid. Did you add a little backer for that triangle to tighten against?

Edited by - Dave Bristle on 02/02/2008 23:03:13

OLarryR
Master Marine Consultant

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USA
3466 Posts

Response Posted - 02/03/2008 : 08:03:39

Another benefit of you upgrading your seacock is getting away from gate and globe valves which are notorious for having some water leakage past their internal seats. The ball valve in your current setup is much more reliable for providing bubble-tight, zero leakage past the seats.

As you now have a new configuration, it probably will last many years with no need for maintenance, etc. Rcmd cycle the valve (shut to open and back) every so often so they do not get stiff to operate.
When I purchased my '89 over 2 years ago, one of the seacocks was very, very stiff to operate. These were the later version that are made of a composite reinforced plastic ball valve mounted adjacent to the hull. I figured if I could get to the valve from inside the hull, perhaps I could shove a slight amount of grease onto the ball and then cycle it to ease up the stiffness. But I was having a hard time getting off the hoses and did not want to exert too much force...boat was in the water. I wound up taking care of it when I brought the boat over for a bottom pressure washing. While they were pressure washing, I came prepared with a little brush and shoved just a bit of synthetic bicycle grease up into the seacock port from outside the hull. When I got back to my finger slip, I cycled the valve numerous times and the stiffness has gone away.

Edited by - on

Deric
Captain

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USA
408 Posts

Response Posted - 02/03/2008 : 08:11:04

Hello Dave,

Yes I plan on placing a backing plate between the triangle base and the inside of the hull. I have read that most folks are using marine grade plywood, some folks have used fiber board, while another has used redwood.

Do you have a recommendation for the backing plate?

I chose using the separate triangle base rather than having a seacock with a triangle base as one unit, because I liked the idea of replacing only the ball valve without having to detach a seacock from the hull.

For those interested, I have included the links to a web site that may help clarify the differences.

detachable triangle base:

http://www.groco.net/new-prdcts-home/ibvf-08.htm

seacock with triangle base:

http://www.groco.net/07-scks-valves/bv-fs-07.htm

Here is a link that I thought had clear instructions about seacock replacement:
http://www.diybob.com/diySeacock.htm

BTW- I am not affiliated with any marine products, companies, or services.
Just someone who is new to sailing.

Edited by - on

Dave Bristle
Master Marine Consultant

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Djibouti
10005 Posts

Response Posted - 02/03/2008 : 10:07:37

Well, for somebody who's new to sailing, Deric, you're certainly on top of this one! For backers in the hull, particularly below the waterline, I lean toward something like a plastic cutting board from your local hardware store. Cut a small piece, round all corners and edges, and bed it into something like Life Caulk (which you can use inside and out). The backer's primary purpose is to prevent concentrated stress from the points of the triangle--you also want to prevent the same from the corners and edges of the backer.

A couple of other things I concluded (that others might disagree with):

1. The galley sink drains best if it isn't sharing the thru-hull with the ice-box drain. Under some conditions, the sink tries to empty into the ice-box, or the ice-box breaks the syphon action for the sink. (The ice-box, to me, was useless except for dry storage anyway--a controversial opinion.)

2. Also to get the best drainage, try to eliminate any upward loops in the hose from the sink to the thru-hull. Air can get trapped and hold up the flow. Sometimes a strategically placed block of wood or wire hanger is all that's needed.

Your '78 is lucky you bought her!

Edited by - on

ClamBeach
Master Marine Consultant

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3072 Posts

Response Posted - 02/03/2008 : 10:30:56

"Do you have a recommendation for the backing plate?"

I used a piece of scrap mahogany and contoured it with a rasp and sandpaper to match the slight curvature of the hull in that area.

Most any wood will work fine even regular plywood as long as you saturate it with epoxy. Side note: You can thin "WEST System" epoxy with acetone to increase its penetration. Bed the backing in 3M 101/4200 or even 5200. As a good practice, be sure to round the corners on any backing plates... even one like this that won't get any loading or flexing.

Edited by - on

PZell
Admiral

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USA
548 Posts

Response Posted - 02/03/2008 : 13:19:40

I had the original set-up which has now been changed. But, PO had also connected bilge pump drain line thru the valve. I left that valve open once and went sailing. Long story short water siphoned back into bilge, pump wore out battery and boat filled up to bunk level with water before we caught it. Whew a close one. Since then I've reopened the bilge scupper hole in the stern and pump bilge out directly there with a protected back flow valve. The new setup under the sink has the mushroom end. I connected sink & ice box there. I feel much better. Just a warning in case anyone else has the bilge routed thru the underwater valve.

Edited by - on

Dave Bristle
Master Marine Consultant

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Djibouti
10005 Posts

Response Posted - 02/03/2008 : 13:35:43

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Originally posted by PZell
 ...Just a warning in case anyone else has the bilge routed thru the underwater valve.<hr height="1" noshade id="quote"></blockquote id="quote">HUGE, HUGE NO-NO! It should be as high above the waterline as practical--right up by the gunwale.

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The Officers, Staff and members of this site only provide information based upon the concept that anyone utilizing this information does so at their own risk and holds harmless all contributors to this site.