Replacing Transom Shower while avoiding eating fibreglass dust.

Published On August 15, 2014 | By Mark Baese | Boat Projects

There are a few benefits to owning a 20 year old boat. One of those benefits is all the extra time you get to spend on the internet trying to figure out if new parts are remotely compatible with old parts. This can also be referred to as take-a-wild-guess-at-what-may-or-may-not-work time.

As I found out in my adventures with plumbing a galley faucet, my boat has some old-timey plumbing that took some trial and error to figure out. Mostly errors, some trial… but it got done.

To say I wasn’t eager to repeat the same mistakes as I try and install a new transom shower would be an understatement. I did however need to replace the unit. It’s needed replacing for a couple of seasons. The handle of the shower was leaking whenever the water system was pressurized – which meant we only ever turned on the water pumps the instant we needed water and turned them off instantly after we were done. This was our temporary solution to keeping the bilge from slowly filling with water from the leaky handle.

This works well with one of the first safety tips I remember learning about boating: water belongs on the outside of the boat.

First a little history. This is what I needed to replace:

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As you can see, the flimsy plastic lid was no longer actually attached to the factory original 20 year old unit. I played with the idea of just replacing the handle and hoses so I wouldn’t need to pull the cup out and have the possibility of doing fibreglass work making the hole larger, etc. It didn’t make sense though as most units I was looking at were pretty much the same price after shipping with or without a fancy new stainless steel holder. Oh, and stainless steel just looks badass.

The other thing I believe I deduced from my research is that the unit above was an old Scandvik unit – or at least it looks like one. One thing I noticed when looking at new ones online, they often mentioned buying a $3 adapter fitting. I still don’t fully understand  the plumbing on my boat, but I do know that I should just buy the $3 adapter and hope that something – either the standard fitting or adapter that comes in the package – will fit my current fittings and hopefully mean zero pipe cutting and messing about this time.

Pulling everything out was simple. Just unscrew the old hose from the plumbing below deck and pull it out. The old unit was cracked and well aged. The plastic was hard and brittle. I’m pretty sure if I dropped it, it would have shattered:

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Again, in my effort to avoid effort – I did my best to find something I thought would be compatible and settled on this very similar and well priced unit:

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It came with a fancy stainless steel holder too. If you look closely at the non-spraying end, you can see an adapter attached to it – and an adapter in a plastic bag in the box. You know what they say about adapters – you can never have too many parts that you will only ever need one of. No idea why it came with two.

The only unknown was how big the hole was under my current shower holder. The new unit was likely to be larger, but I wasn’t sure by how much. I started to remove the old shower:

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It actually wasn’t hard to remove. Just unscrew and remove all the water proof sealant that was under the lip. As you can see, it would need some cleaning up first. Hello knife work.

It also became clear I would need to enlarge the hole fairly significantly:

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You can also see how gross the old lid is here on the right. The new unit on the left was much beefier.

I didn’t have any proper tools that would cut a symmetrical hole big enough, so my plan was to use the Dremel to simply cut a larger opening. Using a Dremel to simply do anything, isn’t really that simple. It should cut fibreglass well enough – but not in this case because the fibreglass was backed by plywood and was extremely thick. The multipurpose cutting bit pretty much didn’t work at all. In fact, it actually flew out of the Dremel when I applied some pressure. That bit is in my boat bilge somewhere – but to this day I have not been able to locate it.

Plan B was to use the sanding drum to just sand a wider diameter. That plan was also a failure. So far most of my trial and error is ending in error.

Plan C was to use the stone grinding drum that you use to sharpen tools to sand a wider diameter. That worked. It created lots of heat and dust which meant slow going. I’ve also heard that inhaling fibreglass is frowned upon by doctors and medical professionals. I did my best to mitigate the damage while hoping this photo wouldn’t land me on any watch lists:



The hole re-sizing was the most difficult part of the gig – and really, it wasn’t that bad. Once that was done, I was able to start using 3M Marine Sealant to put the new holder in and screw it down.



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This next photo it’s really messy, but I wanted to ensure it was waterproof since we splash a lot off he swim platform. I figured when it dries, I can scrape off the excess I couldn’t clean up here.

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In the above photo you can also see a slight crack in the holder in the right. That was me being manly and trying to jam things that were too large into too small of a hole. (Insert innuendo here). It doesn’t make a difference though and you can’t notice it with everything in place.

Here it is a little more cleaned up – and works like a charm:

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The best part is the adapter fit like a charm – and zero leaks.  We don’t leave our water pump on overnight or while we’re away from the boat because safety – but it’s nice to leave it on when we go out for the day and not worry about leaks.

I’d peg the difficulty of this project as relatively easy. The hardest part was making the hole bigger – but not too big. It took a while, but once that was done – everything slid right into place and connected properly.

A side benefit on replacing the leaky unit is that this shower now sprays further. Not sure if it’s just better that way – or if the spray head is just cleaner  without 20 years of crust built into the inside. Either way, things are much better looking and working.

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