Today I replaced 3 seacocks…(it actually took a month)

Excalibur has Marlon plastic seacocks in the heads and the bronze seacocks for the cockpit drains and galley sink were either seized or on their way out. I decided to replace the bronze seacocks with plastic seacocks as they’ll be less maintenance, and everything else connecting the seacocks are plastic so there’s no reason to be superstitious about these new plastic fangled seacocks!

Here’s a couple of Marelon videos if anyone’s interested:

First job was to remove the old seacocks. Queue a new tool, a gigantic wrench called ‘Faithful’ ( it’s actually written on the wrench).

Unscrewing the seacock from the skin fitting was pretty impossible. With every turn of the seacock, the skin fitting would rotate. The skin fitting had no notches on the inside (like new ones do) to allow anything to be inserted into the skin fitting to stop it rotating while the seacock was unscrewed.

Queue the angle grinder. Taking an angle grinder to a newly acquired boat was not desirable, but it was essential. I basically angle grinded the skin fitting down from the outside as carefully as I could. I’ll let the pictures do the explaining.

I was then able to pull the seacock and the remainder of the skin fitting which is still screwed on to the seacock out.

After this I took my new skin fitting and discovered it was slightly bigger than the previous hole. Queue a rasp and some elbow grease. I enlarged the hole and primed it with primicon.

I’ve cut some backing pads out of exterior plywood which I painted with bilge paint to protect them further from water ingress. People seem to have mixed opinions about plywood backing pads. I shall keep an eye on them, but don’t expect them to get sufficiently wet to degrade as quickly as some people thing they may do. Time will tell.

I removed the old pipes off the cockpit drains.

We (I had some help) sikaflexed the white skin fittings  and pushed them through the holes in the hull, slid the backing pad on (which had more sikaflex on), and then screwed on the stop cocks. We did a dry run first off with no sikaflex to position the seacock handles as desired.

The next job was to join the cockpit drains and galley sink to the stop cocks with some new piping and jubilee clips.

I used a combination of a heat gun and a wooden bung to expand the pipes as the cockpit drains and the galley sink outlets are slightly bigger than the 1 1/2 inch piping that force4 supply.

2 pipes went on relatively easily, but fitting the pipe on the cockpit drain on the starboard was infuriatingly difficult. I spent a good day upside down trying to get the piping on. I can’t relate how I spent heating up new bits of piping, shoving wooden bungs up the piping then cooling it down. I eventually gave up the next day and called it quits, when a fellow sailor for the yard dropped by a bit of piping after hearing my woes. After 15 minutes I successfully got the piping on, the piping was only a few ml bigger, but it made all the difference.


The job took ages to do, mainly because I had to wait for parts to come in, and it either rained putting the job off, or the chandlery ordered the wrong size parts. It was an infuriating project, but I’m glad I did it. I probably saved about £300 doing it myself, and I learnt something, so not all bad.


The boat is now in the water, and out of 3 seacocks, 1 of them is dribbling. The leak isn’t enough to take it out of the water, but it’s enough to annoy the hell out of me. I would take a guess that its not the skin fitting thats leaking. I put lots of sikaflex arount the skin fitting so I dont think water is coming in from there. My guess is the water is somehow coming up through the seacock and then running down the inside of the thread between the seacock and the skin fitting thread.

On the seacock handle is a little white round piece of plastic, which if you pull it out is a plug. The plug fits neatly into the skin fitting on the outside. I intend to plug the skin fitting. If the water stops dribbling out then I know the leak is coming from the threading and not from between the sealent and the skin fitting  (if that makes sense)



Author: Tim Butler

Related Posts

No Comments

Leave a Reply