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Cutting out the Bulkheads.

By Dermot Tynan, about 8 years ago.

A slight change from the version of the hull from The hull starts to take shape.; the hull height from the base of the hull to the deck (not including the keel) was 180mm. As I started to look at cutting bulkheads and the transom, it struck me that the hull is quite shallow. It looks fine from DelftSHIP but that's a low freeboard.

The beam of the boat is around 360mm, which is twice that depth. The original intent was to create a hull which wasn't too "beam-y" but that's a 2:1 aspect ratio. I decided to increase the hull height by 50%. Luckily, DelftSHIP will scale your drawing in any or all of the three vertices. So, five minutes later, and we have a new hull with a 270mm depth.

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Wind Direction Indicator

By Dermot Tynan, about 8 years ago.

Now that the hull is looking solid, it's time to start thinking again about the wind direction indicator. It is possible to detect wind speed by using an ultrasonic sensor and receiver, and measuring the delay between the two. You need to account for temperature changes and gusts can cause issues, but it is fairly reliable and has no moving parts. Generally, you use two transducers offset by a distance of perhaps 20cm for the North/South computation, and another pair in the East/West direction. I think if we were using a larger hull, such as a 4m boat, this would be a good plan. But, for the 2.4m (or the 1.2m) boat, it's just too big and awkward. Also, this jury is undecided about how well they would work, over the long haul.

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The Marvel of 3D Printing...

By Dermot Tynan, about 8 years ago.

So, while debating the different merits (or otherwise) of various mounting solutions, someone suggested using a 3D printer to actually print the housing for the masthead wind direction indicator. The more I thought about that plan, the better I liked it. As it happens, 091 Labs in Galway have a working 3D printer, from the Mendel90 family. What's more, they are trying to get a 3D printing service off the ground! I wasn't customer number one, but I was probably pretty close.

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First signs of weathering.

By Dermot Tynan, about 8 years ago.

In order to test the spiffy, new Wind Direction Indicator mentioned in The Marvel of 3D Printing..., I assembled the mechanical components (without the potentiometers) and mounted it outside. As we live in a wind-swept area, with a high concentration of sea salt in the air, it was a useful test of how the system would perform. What I couldn't test was the effect of high temperature/humidity in a salt-water environment. To do that, I'd have to move to the Caribbean (which seems like a good idea, given the Irish summer we've had so far!).