DIY Sopranino Ukulele Part 1

Ok – there are lots of things I’m supposed to be doing but here’s another project just for fun. I’ve long wanted a Sopranino Ukulele but I can’t really afford one, plus it would be fun to have a go at making one.

A Sopranino is smaller than a Soprano Ukulele – the Soprano has a scale length of around 13″/330mm and the Sopranino has a scale length of around 12″/305mm. One big advantage of this size is that I can resaw the timber on my mini-bandsaw which has a capacity of around 75mm.

This is the concept I came up with:

Design for Sopranino Ukulele
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New Daggerboard for Owl – Part 1

Owl needs a new daggerboard. The current one is plywood and might be getting weak. Given I might need to stand on it to right Owl after a capsize this needs sorting.

Owl’s daggerboard – a big slab of plywood

Plywood is generally a bad idea for centreboards, daggerboards and rudders on dinghies as half the wood grain is running in the wrong direction. Once the thin outer skin buckles there isn’t much strength left to hold it all together. In any case it looks like Owl’s daggerboard has the outer skin of the plywood running across the board rather than down it – unconventional although this might be deliberate to put the load into the thicker underlying plys.

The board is 16.6mm thick, 410mm wide and overall 912mm long including the handle on the top. The part within the boat (dagger board casing) is 345mm.

Design considerations

The daggerboard is currently too far aft. I don’t think this hull was ever really designed as such – the fact that the original rudder only just touched the water is a hint – and the daggerboard case is too far back. If I taper the back edge of the daggerboard somewhat this will help a bit. Making the daggerboard longer will help the aspect ratio but also making the board harder to handle. Still a bit longer should be ok.

Given how thin the board needs to be, the profile is going to have to be Neil Pollack’s design for a parallel sided foil. I’ve put this into a spreadsheet for ease of use.

Other Owl Jobs

I need to re-finish the woodwork – this was done in Woodskin so that shouldn’t be too hard once the weather warms up.

I would like to get more buoyancy into her – I don’t have a huge amount of confidence in the built-in buoyancy given the design standards of the rest of the boat – so a couple of buoyancy bags under the seats wouldn’t be a bad idea. I will need to mend one of the seat supports and make sure everything is strong enough to take the load.

Filthy device

The dirtiest electric motor I’ve ever seen

I tried to fix my other half’s electric mixer and the inside was so filthy I had to share it. This is 20+ years of flour and cocoa powder. Actually very well made – all metal mechanism and the electrics are fine. However the wormwheels are stripped after mixing heavy mixtures for all that time so not viable to fix 😦

Wanderer Dinghy – buoyancy and ballast

Overall I’m very happy with the stability of Custard – my Wanderer dinghy. I’ve never had any concern about capsize. The junk rig helps with this – it is very easy and fast to reef as the gusts are coming in. It is also easy to put up full sail again when the gusts have gone through so there is no temptation to avoid reefing.

However. there are times when capsizing would be a really bad thing to do. For example, when older people are in the boat who would be impacted by immersion in cold water and would find getting back on board very hard.

There is a version of the Wanderer equipped with a steel centreboard. This apparently makes the dinghy very hard to capsize. However, it also increases the weight of the dinghy by about 38kg making the boat much harder to pull up a slipway and move around on land. Online opinion seems to be that while this works, one might as well get a Wayfarer and sail it heavily reefed.

The Wanderer does have floorboards, and it occurred to me that there is enough space under the floorboards for about 40l of water; i.e. about 40kg of water ballast. This could be pumped out before trying to get the boat up the slipway, or just when the wind was light.

Alternatively, I have a pile of old bricks at the bottom of the garden. Each brick weighs about 3.2kg so I’d only need 12 bricks to get to 38kg. Again, the bricks would be easy enough to put in and take out as necessary.

I sanity checked the question on the DCA forum and people seemed very supportive of the idea, so when I get time I’ll have a go and see what happens.

I’m also planning on getting some buoyancy bags for under the side-decks. The existing buoyancy is under the side seats. This works ok at keeping the boat afloat and limiting the amount of water sloshing around, but doesn’t help stop the boat capsize once water is coming over the side. If the top of the sides was buoyant this would help the ballast pull the boat upright.

I’m still working on getting Custard waterproof so this isn’t going to happen soon – I’ve got to get the front rubbing strip back on and sealed up first. Owl – my other boat – needs a new dagger board so that also needs doing. The current board is about 40 years old and plywood so I suspect it will snap off, particularly if I needed to use it to recover from a capsize.