Thru-hulls are going in

Friday 8 Oct, re-launch 2021, HHN day 9: A full day preparing all fittings for the 5 thru-hulls, then fitting 3 out of 5 backing plates.

Up nice and early again. Well, you have to be this time of year because the daylight has gone by 6.30pm these days. Today was a full day on thru-hull fittings. 2 of these thru-hulls are for the deck-scuppers, which drain just under the waterline. These are a little bit over-engineered, because most boats just let water on their decks run off the side decks into the sea. But not Hallberg Rassy! Water running down the hull leaves dirty streaks, so HRs have their deck water deposited to the sea where no one can see it happening. And no dirty streaks either. Anyway, I digress.
There are 2 scuppers that drain into each thru-hull. Their hoses join at a very fancy brass Y-piece fitting on top of the seacock. Replacement Y-pieces are impossible to buy in the USA with NPT threads. Hence, I need to save the originals, have their BSP threads cut off and new NPT threads cut. Pfff, quite an ordeal. But must be done.

So, first thing in the morning it’s off the Stephen’s (East Coast Rigging) shop, with a number of things to do there. Firstly, remove these Y-pieces from the old pipe work. To do this, I heat the connections with a propane torch to liquify the magic Hallberg Rassy pipe-glue (Loctite 275) Then, with some effort, unscrew the Y-pieces I need to save.
Next job is to shorten all the mushroom-head thru-hull fittings to the correct length, so that each one doesn’t quite bottom-out in the seacock, which allows the seacock (inside) and the thru-hull (outside) to tighten snugly from each side of the hull. Each thru-hull needs about 15mm cut off its length. I start with a hacksaw, but then Stephen sees me and suggests using his belt sander. I didn’t think a belt sander would do the job, but I was very much wrong. With super coarse paper, it ate the bronze fittings like I was sanding soft wood! You learn something new every day. And I have to say, from Stephen in particular, I learn a lot!

Then it’s a short trip to see Freddy, at Phipps, to have the NPT thread cut on the Y-pieces. Which he does by the end of the day.

Back at the boat, the next task is to dry-fit all the fittings into their respective holes in the hull and check all lengths and orientations will work out, such that the hoses fit back on OK. A few alterations there, but in the end, we are good-to-go for epoxying-in the backing plates to bond them to the inside of the hull, for the seacock(s) to sit on.
To do this, I use Six-10 epoxy with some added fibre-balls so that it becomes a thick paste. The objective is to put a thick layer on the underside of the backing plates (3-5mm) then dry-fit the thru-hull into the seacock such that the backing plate squeezes the epoxy out the sides. And at the same time, and most importantly, this ensures the backing plate is exactly parallel to the outside of the hull so the thru-hull (outside) and seacock (inside) sit perfectly flush … and not squint with gaps around it.
Doing this needs 2 of us, Oana on the inside holding the seacock screwed to the epoxied backing plate, and me on the outside screwing in the thru-hull until is touches flush with the hull, then tightened until Oana tells me the epoxy has squeezed out all the way around the outside of the backing plate. Then it’s done. Just needs time to set.

Just before we go to bed, I remove all the fittings while the epoxy is still not quite cured hard, to ensure I can actually get them out!
OK, you got all that? Good! You can do it yourself next time 😊

At the end of the day, we have 3 of the 5 backing plates epoxied neatly into place. Tomorrow we will finish the last 2, then paint inside and out with Interprotect-2000 (epoxy paint) to ensure all surfaces are sealed water-tight, before actually screwing in the thru-hulls using 3M 5200 sealant. It’s all quite a job, and one I’m really looking forward to ticking off the to-do list.