Plastic knot meter thru hulls

[Hesper(II)]

First-thanks Tim for setting up my new account. Lost/forgot my password but i promise to keep it close to me from here on in....

So, just bought a Morgan 24/25. We won't have much chance to work on her this winter as it's a good 1 hour plus trip to the boatyard but come spring, we'll do some work including seacocks etc. But, when I was at the boat this past weekend, I pulled out the paddle wheel assembly for the knot meter and realized that the thru hull is plastic of some type. Am I being paranoid thinking that with all the concern about bronze thru hulls and seacocks and ball valves etc that that plastic fitting could sink my boat? Should I just start whittling an emergency plug and hope for the best?

Thanks

Jim

[Tim]

They're hardly ideal, but they're everywhere, and rarely cause trouble. I have one.

[Hirilondë]

I wouldn't be paranoid about it, but having DC Plugs handy is never a bad idea. Offshore races often require them to be tethered and ready at the site of every thru-hull. I would at least consider having all the needed sizes in some central, easy to access location. You can buy them, like these: DC Plugs or whittle your own ;>)

[Bikermouse]

I noticed the same problem and worry on my Cal. I had been planning on replacing all the other plastic thru-hulls with "real" thru-hulls and seacocks with wooden plugs attached. Problem with the plastic transducer housing, though, is that it seems that a) unless the entire transducer housing falls out of the thru-hull in one piece, a wooden plug wouldn't really find a good place to fit. b) if you tried to shove a wooden plug into a plastic fitting, I'm afraid that the plastic would just shatter, making whatever problem you had exponentially worse.

As an emergency measure, for this fitting, I think that instead of a wooden plug I'll attach a short piece of hose with a plug permanently attached at on end that would fit snugly but easily over the plastic fitting, along with a few zip ties to snug it down and secure it. Just cut the wires, slide the hose on, and secure with a zip-tie or two.

Does that sound just stupid? As Tim stated, I'm guessing that there's about a 99.99% chance that I'll never need this emergency system, but I think that this system will give me the most peace of mind.

[Tim]

I think it really goes without saying that any boat, with any installations, should have some basic plan in place for dealing with the unknown and the potential some dire emergency someday. This plan might be the ubiquituous wooden plug, or even just stuffing a hole with whatever one can find on board--rags, clothing, cushions, whatever.

A bad hose or clamp is far more likely to cause a serious water ingress problem than a failed through hull (of any material) on any boat. The instance of failed through hulls that cause serious problems or sinkings is pretty darn small. Even the cheap plastic ones and the ball valve-on-incompatible threads that we all love to rail against.

Boats sink (usually at the dock) mostly from ignorance and neglect, not true equipment failures. So make your plan as makes you comfortable, as we all should, but then move on and worry about the real stuff.

[Hirilondë]

Rags forced into the opening can stop, or at least significantly slow water coming in. Probably the best thing is knowing where all of your thru-hulls are, and having a plan which includes the implements needed. Figuring it all out while you are sinking is probably too late.

As an emergency measure, for this fitting, I think that instead of a wooden plug I'll attach a short piece of hose with a plug permanently attached at on end that would fit snugly but easily over the plastic fitting, along with a few zip ties to snug it down and secure it. Just cut the wires, slide the hose on, and secure with a zip-tie or two.

Does that sound just stupid? As Tim stated, I'm guessing that there's about a 99.99% chance that I'll never need this emergency system, but I think that this system will give me the most peace of mind.

This sounds like a plan, it includes implements and it gives you peace of mind.

LOL, was posting this and got the message Tim had just replied.

[Sailor Simon]

One could consider removing the fitting(s) entirely and using a GPS for true speed over ground. Now one need only concern over extra batteries instead of holes in the hull. The less holes in ones hull, the better. Sailor Simon

[Rachel]

One could consider removing the fitting(s) entirely and using a GPS for true speed over ground. Now one need only concern over extra batteries instead of holes in the hull. The less holes in ones hull, the better. Sailor Simon

True, although sometimes it's nice to have speed-through-the-water --- which you can then compare to speed over ground for additional information. A knot log will do that without a through hull, but I think that would be a pain inshore.