@ bill good again:
Regarding catching dinner in your saltwater intake: although I know people who've done this, it has only happened to me once, and it was an eel.
(NOTE: the word "YOU" in the following is not aimed specifically at you, Bill, but at anyone reading this, which helps me realise that may well also applies to your post, and its applicability to the usual situation, where the saltwater pump is stand-alone)
Although it was evidently a large-ish eel (the inlet was quite sizeable) I'm guessing it was stressseed out and somewhat stretched and lengthened by circumstance and suction alike on insertion, because it showed all the signs of being a large (and long, and VERY tough) plug
in a smaller diameter hole. Not good news.
I like standpipes (mainly used on metal hulls, but can be applied more widely under certain controlled circumstances) because what happened to that eel was that the bit outside the boat, and the bit in the flexible hose, both became sustantially larger than the bit in the non-expanding metal ball valve and thru-hull. This caused it to develop a wasp waist (although of course much more subtle) and meant that trying to use air to force it out would have just enlarged the eel, which had gone in head
first as you would expect, and things would no doubt have gone quickly downhill from there. Bear in mind that one did not at the time KNOW it was an eel.
Ideally a standpipe would be a conical bore, reducing gently all the way up to the waterline .... but that would use a great deal of material to do from solid, and I don't fancy welding it.
In the case in point, we had some joiners, but no long lengths of suitable hose spare, but IIRC we were able to leave the eel as a guardian of our watertight integrity (he was certainly a hell of a lot more "integrated" than the mandated 'soft wood plug') , cut the hose off inboard of his head
, and splice the remainder to a less essential hose leading to another thru-hull which was re-purposed.
INCIDENTALLY: on the "softwood plug" topic: I didn't realise until the occasion arose that there is actually a good feature in the fact that the taper is always too bloody steep. I always realised it was to extend their diametral range, but it bothered me that as a result they did not stay in place.
The "good feature" I mentioned is this: Provided you have spares of each size, (which you should do, as usually many thruhulls on a given boat will be the same diameter) a good way to go about things is to use the first for two purposes: Ram it in the offending hole, and get someone to lean on it. Take an OTHER identical plug
, and mark on it the amount protruding from the first one, which is being used for immediate relief but also as a tapered gauge: a primitive but effective way of measuring holes.
So now you whittle away the second plug, starting a little way towards the smaller end from that point and working towards the BIG end, so you end up with a much shallower taper starting at a diameter which, as well as you can judge, will go about an inch into the fitting.
And the softness of the wood should do the rest.
Don't smack it in too hard, especially if you made a really shallow taper, or you will risk splitting the fitting, especially when it swells and is unable to back out.
If you have a Zyliss vice (I forget the model) and a galley
bench to clamp it to, you can use your electric
as a lathe headstock in the supplied clamp, and use the Zyliss tailstock, and make a superb job of it ! But whittling (or, quicker, a decent wood rasp) will do just fine.