Microtransat

By Dermot Tynan • May 4, 2013

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.

By Dermot Tynan • May 16, 2013

The new ALIX board has arrived. It's to the left of the picture, sitting on top of a copy of the Lyon's Notes (which is appropriate). It's running my custom version of NanoBSD quite nicely, and can see the GPS without any difficulty. The GPS unit is a BU-353 unit (the USB version) which is out of the shot. It's attached to the window, and gazing at the man-made stars. To give a breakdown of what's in that photograph, the ALIX is on the left. In the USB port is the GPS, the RS-232 cable at the top of the board is communicating with my development machine (running FreeBSD). The red CAT5 cable is connecting the board to the "house network." The Atheros CM9 radio is a miniPCI card mounted on the underside of the board. It works on 5.8GHz and on 2.4GHz. In this case, I'm using 5.8GHz because (apparently) it has better cross-water characteristics and the band isn't as crowded. The mini coax cable is at the top-left of the picture, connected to a short, 9dBi antenna. You can also see a 12v cable with barrel plug. At the top-right of the picture is a WRAP board, also developed by PC Engines. It was being used as a testbed for the operating system, but that is no longer needed thanks to the ALIX.

By Dermot Tynan • May 30, 2013

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.

By Dermot Tynan • June 3, 2013

After a lot of sanding, fibreglassing and applying resin, the hull is looking like it is ready for salt water. As you can see from an earlier post (Hull 001 is almost ready for fibreglass), the hull is formed by gluing thin balsa strips to the plywood bulkheads. These strips give the hull its shape, and also provide a modicum of structural integrity. On the outside of this balsa, are 3 layers of 300g chopped-strand matt, finished with a layer of fibreglass tissue. Each layer is impregnated with polyester resin. Likewise, the inside of the hull is coated with two layers of 300g CSM. Ultimately, all of the balsa wood is covered with at least two layers of fibreglass, which is a good idea because fibreglass on its own isn't that strong, and is susceptible to rotting, particularly in warm, humid waters.

By Dermot Tynan • June 7, 2013

As the hull is now watertight, and we're mere weeks away from having a sealed hull with keel and rig, it's OK to start looking at actually getting this thing to sail.

Up until now, I've been somewhat obsessed with getting the physical aspects of the boat to a certain juncture. The reasoning is simple; until there's a boat, all of this other stuff is just a waste of time. Well, now there's a boat...