Precision Required

It’s still March (2020). It’s BCSD¹ as far as the blog is concerned (just). Loyal readers (all two of youwill notice that there is no time lapse video in this post. The management apologies for this omission – it was initially due to a memory lapse by the operator and then a shortage of critical equipment meant that this facility was temporarily unavailable.

It’s time to fit the centre board case. As they used to say on Blue Peter ², it’s something I made up earlier – a hollow open sided rectangular box about 4 ft long x 2 ft high x 2 inches wide ⁵. The long top and bottom sides are open so I leave you to imagine how flexible the whole thing was.

The snag is the inside needed to be lined with glass fibre cloth and I could not work out how to do this after the box had been assembled, so I made it in two L shaped pieces – each consisting of a big side slab and a little end flap. Glass fibre cloth was epoxied in place on the inside surfaces of the L and then, once everything was fixed but not totally cured, the two L were married together. Thickened Epoxy was slathered over the inside of each end and a piece of glass fibre tape was lowered through the slot and pressed firmly into the goop. Not particularly pretty, but I hope effective.

Now back to fitting the slot into the hull.

I needed to climb into the hull. This would be the first time I’de attempted this feat. Would it take my weight? The hull has a 4 foot long slot in it where the centre board case will fit, between the left and right (oops, port and starboard) sides of the bottom plank (sorry, plank 1 ⁷). So the bottom of the boat is quite bendy without the slot glued in place. Fortunately, the underlying trailer has a convenient transverse beam in the right place and there were a few pieces of 18 mm plywood lying around so a pair of supports were made to hold up the planks and there was a space for the centre board case to fit between them as it  protruded through the hull.

I climbed gingerly into onto the hull – there were a few creaks and groans but no rending sounds so the first test was passed. The centre board was “offered up” and the slot was found to be slightly short. Easily fixed with a rasp.

But then the implications of this slot hit home – if it wasn’t lined up longitudinally and vertically true to the hull, the centreboard would be all wonky and she wouldn’t sail at all well.

Back to all that wearing alignment of the hull with the laser guide. I needed to use the camera mount to hold the laser level…(in this case for a vertical line).

Laser display

This turned out to be quite simple and the case was soon lined up and tack glued into place.

The following day I mixed up lots of Epoxy, thickened it with filler, wetted the joints with un-thickend epoxy, soaked yards of woven glass fibre tape in un-thickened epoxy and glued the case in place with lovely filleted joints.

Phew.

Notes

1 Before Corona Shut Sown

2        

Blue Peter ³

                                                                              

3 Not that Blue Peter (international code flag P). I mean the childrens programme on BBC TV (is it still being shown?) where the presenters made stuff using sticky backed plastic 4

4 I never got a badge

5 1.2 x 0.6 x 0.05 metres. ⁶

7. See nomenclature in a previous post “And a few steps back”

8 I’d left the laser display board at home and Samantha too ⁴

9 Apologies to I’m Sorry I haven’t Clue and the late Humphrey Littleton.

Mad March winds

It’s now (in real time ¹ ) the second week of March. The last three weeks have seen almost continuous rain and strong winds across the UK. But the builder and the owners agent have not been here to experience them. We’ve been skulking in the antipodes, in relatively benign conditions (except where we particularly needed clear weather). Now back in the UK we find the local intermittent chalk stream in full flow – the first time for over four years – as the water table has finally risen above the spring line. The local fields are sodden and trodden into seas of mud by cattle or horses. But the daffodils are coming out and there’s even a sign of green leaves on the local blackthorn.

Enough of these nature notes: I wonder how the cow boatshed had survived this turbulent atmosphere.

So, we awaken Martina from a four week slumber and trundle north west, along the valley road. Then up rocky lane, passing a sea of mud where HS2 work is restarting. Through the various copses before turning onto the farm. Still up, past the old chicken sheds, turn left by the yellow (sometime) site office, towards the bonfire site.

Somebody has helpfully put a skip in the way. Turn towards the scouts canoes and then reverse down the track to park outside the shed doors. But do make sure you miss the old site loo.

So far, so good.

Past the scouts canoes, a digger other useful stuff

The empty plaster tank is still there – so perhaps no one has been in. Slide it away and open the doors the would be boat is still there – a trifle damp and dusty but unchanged from when I last worked on it. It’s blowing hard outside, the roof creaks and groans and the sliding doors rattle on their rusty tracks. But we must get on.

Mind the old loo

The doors had not been touched!

Bring in the tools. Light the fire. Fetch the water. Today is rubbing down day.

Before I left at the end of January, I had tacked in place a couple of longitudinal bulkheads that make up the cockpit sides. First positioning them and holding them in place with cable ties and then “tack welding” their edges in place with little strips of mixed epoxy.  I’d put the sides and end of the engine bay in, too and held the transom against them, using the former supplied to bend it to the right shape. All these “tacked” joints need  to be roughened with sandpaper before a glass tape covered fillet can be laid over the joints.

So that’s todays weary task. The spaces are too small to get at with an orbital sander, so it’s all to be done by hand. The dust gets everywhere. The vacuum cleaner ² howls in the background in an attempt to keep it down. I’d forgotten to don my overalls, so my clothes became dusty too. My hair became whiter that ever – but a least I had had the sense to wear a dust filter mask.³

After several hours of finger and hand weary work, the job was done, the obvious dust cleared from the boat and the joints all rubbed over with a tac rag or two. ⁴

Another day: now to start filleting the joints.⁵

Filleting a joint makes the glue joint very strong. You mix up a large lump of polyester resin and hardener and mix into it a filler material that bulks it up and makes it stiffer. This is then spread along the joint and shaped to make it appear a bit like the coving between a ceiling and a wall. Then glass fibre tape is coated with more mixed resin (this time without the filler) and laid along the joint, Two or three layers are applied. It’s very messy and sticky and has to be done quite quickly otherwise the resin will set before you have finished.

The joints between the longitudinal bulkheads and the planks of the hull were each about 3 metres long. It took me ages. Then there were some fiddly small ones to do around the engine housing. But they are yet to be done.

I hope that I can now walk on the inside of the hull so that I can put the centre board case in place.

Almost looking like a boat

Notes

1. Now there’s a phrase that’s worth conjuring with.  It seems that neither physicists nor philosophers can agree on what time is or how it is made up, let alone why it can’t run backwards.
2. Not the household one, the owners agent takes a dim view of such items being misappropriated for unofficial uses. It’s the one used to clean out the pond.
3.  was not trying to avoid  Corona virus – having spent several hours in the terminal buildings in Hong Kong last week, I don’t think there’s much point. I’ll just self isolate in the boat shed for a couple of weeks
4. If you haven’t come across these things, I recommend them for the final clean of surfaces before they are painted. The tac rag is a cloth impregnated with some sort of sticky stuff (a bit like a fly paper, I suppose). When you rub it across a surface that you think is clean it’s amazing how much stuff is picked up.
5. No, I’ve not started a butchery business (although, looking at the quality of the carpentry, some might think so).