The Boat Tinkerer: Episode 45 Electrifying Sandpiper Part 1

Sandpiper came without electrics (not counting the battery-operated cabin lights). There are good reasons for this, other than keeping the price down. There is less to go wrong, and there is a lot of fun to be had on boats without electrics. People have been sailing boats for millennia before the likes of Willam Gilbert and Sir Thomas Browne discovered magnetism and electricity in the 17th Century. (Benjamin Franklin’s later experiment with a kite in a thunderstorm seems to have been embellished, which would have helped his political ambitions).

Also, there is a lot you can do with small battery-powered bits and bobs. The cabin lights have been mentioned. I now have a battery-powered radio. Other owners use battery-powered outboard motors. But, the list is limited. What about a depth-sounder/fish finder (like the one sitting in my drawer)? Or an auto-helm (like the one sitting in my drawer)? Or the occasional trip with a portable fridge (like the one sitting in my caravan)? Or some electric pumps to pump out the ballast, or to pump freshwater to the tap? True, these latter items are on the nice-to-have rather than must-have list, but the list could expand endlessly with an electrified boat. There are also good reasons to install electrics.

Like other Cygnet owners, I have thought long and hard on this topic. The very last thing I intend to do is to drill a hole in my shiny new boat, which is exactly what I would need to do to install cables tidily. My strategy, then, is to put off this fateful day as humanly possible, if ever I were to change my mind. I need to develop the electrics in a reversible way, being as unintrusive as possible. Further, the Admiral would never forgive me for making some horrible alterations to the pristine Sandpiper (and she has first-hand experience of my capabilities in this regard).

The strategy I have decided upon is to make a demountable plywood base plate that could be bolted and unbolted from the starboard bulkhead (the wall between the cabin and cockpit on the right hand side).

But, how can you fix bolts to the bulkhead without drilling holes? I’m glad you asked. The answer is to use stainless steel tee-nuts glued to the bulkhead. They are small and don’t need holes. The worst that would happen, with this approach, is that I would be left with the tee -bolts glued to the bulkhead.

The first challenge, then, was what glue to use. I could have used epoxy resin, thickened with a filler to make a gooey paste. Epoxy resin does not flow fast, but it does flow far. I wondered if the epoxy resin would form dribbles and snots on the bulkhead, which leant at an overhanging angle of about 10 degrees and seemed perfectly oriented to create these unwanted features. Also, I only wanted a small amount, probably less than the smallest cans of resin and hardener. After staring at the big shelf of Sika products in the Bug Green Shed for fifteen minutes or so, I decided to buy a tube of Sikabond 145 Supergrip, which promised to glue anything to anything with a rigid bond. I did not want something that would flex and creep.

Before taking the glue anywhere near the boat, I gave it a trial. Not having a suitable piece of fibreglass to hand, I glued a tee-nut to an aluminium square tube, after roughing the surfaces with an angle grinder. I hung some weights off it, using plastic bottles filled with water for the weights; 1 litre being 1 kilogram.

On my first attempt, I found that the glue had not set in the centre of the tee nut. It seems the Sikabond 145 cures with exposure to the atmosphere, like Superglue and other C3 glues. As the stainless steel of the tee-nut and the alumium proxy for the fibre-glass formed perfectly hermetical seals, the centre of the glue blob took longer to cure than the rim. I tried again and waited three days instead of one.

This time, the glue blob had set, so I started attaching weights, working all the way up to 11kg (I ran out of plastic bottles and buckets) and then left it. A week later, I was pleased to see the assembly still holding the weight with no sign of sagging or creeping. The glue worked as I had hoped.

The next step was to cut a plywood plate to shape. I used a tick-stick on a piece of cardboard salvaged from the greengrocer’s bin and worked on a blank. I was pleasantly surprised to find I could cut the bulkhead plate and the battery tray (more on this later) from a single piece of 6mm plywood that I bought, again, from the Big Green Shed. With a little trimming and shaping, I formed the plate to fit snugly onto the bulkhead with its port side tucked beneath the companionway trim.

I drilled holes into the plywood baseplate where I wanted the tee-nuts so I could use the baseplate to hold the nuts in position as the glue cured. I had to invent some Heath-Robinson struts to push the baseplate against the bulkhead, using some scrap strips of ply and an extendable broom-handle.

With a wire brush, I scuffed the spots of the bulkhead where the tee-nuts would go. I stuck packing tape to the plywood to de-bond the cured glue, applied my blobs to the tee-nuts and set the thing in place to cure overnight. I did not want to leave it until the glue had set completely, as it might have bonded something to something else more permanently than intended.

I was a little too hasty in removing it the following morning. I had not covered the whole surface of the plywood with packing tape, so wherever the glue touched the plywood, it set. The glue also did not fully set between the tee-nuts and bulkhead, causing some tear-out on the rear face of the plate. The overall effect was that the glue had fully set where I did not want it to set, and it had not set where I wanted it to set, causing me to knock the tee-nuts out of alignment.

I decided to nudge the tee-nuts back into alignment, only to find the glue setting as soon as I moved them. Thankfully, I got everything back to where it needed to be. After re-assembling my Heath-Robinson struts, I left it, again. A week later, I took off the baseplate and found the tee-nuts solidly set in place, needing some trimming of excess glue.

The bolts were made from cut-down button-head bolts from the local nut and bolt shop. A tip for cutting down bolts with a hand-held hacksaw is to fit a nut between the cut and the bolt head. This provides a flat, adjustable surface to cut against, protects the thread you want to keep, and helps knock off the inevitable burrs when you unwind the nut. If you have ever attempted to thread a nut onto a cut bolt, you will know the fiddly nuisance those burrs can be.

Finally, in this episode, I roughed up the sides of the boxes that I will fit onto the plywood baseplate and bolted the assembly in place. If it survived the road trip to the boat club, and a Sunday afternoon race, it would probably last a while. Thankfully, it did.

Now, the magic of my demountable system truly starts. I took the baseplate home to work on it further whilst leaving the boat in its parking-bay at the club.