With the first round of scale model testing complete (and the second round rapidly approaching), Mark’s finished analysing the results from the towing tank. Torpiddilies 1, 2 and 3 were tested for hydrodynamic drag at various angles of yaw and also had their seakeeping abilities examined using the towing tank’s wave maker. Video footage of the tests, conducted at Newcastle University, can be seen below:
The graph below shows the hydrodynamic resistance of the three hull forms at various speeds and at zero yaw. Torpiddily One has the form of the existing Phil Morrison-designed rowing boat, number Two is based on a traditional yacht and model Three is a stability-orientated shape featuring a tunnel hull and a Deep-V anti-slamming bow.
With a much greater wetted surface area, Torpiddily Three shows much greater drag. However, the yacht and rowing boat designs show almost exactly the same resistance. What’s not shown here is how this trend changes with yaws up to six degrees – when the yacht design, with no skeg, proves to have the least drag.
This is just a small example of the large amount of data that Mark gathered from the first batch of tests. He’s now refining the hull shape in to three iterations based around the yacht design, which once again will be machined by Concept Group International in to foam supplied by John Burn Ltd. At the same time, Mark and packaging and ergonomics expert Alan Ramsay are progressing with the digital packaging model – soon we’ll be starting the build of our physical packaging buck, to make sure that the cabin, cockpit and living area are all big enough for us to live, work and sleep in. Drivetrain designer Ivo is also refining his concept, and a specialist company called Bruntons have started working on our custom low-speed propeller.
In other news, we have some more interesting and important meetings coming up. We’re heading down to Plymouth again in a couple of weeks (right after the second round of scale model tests), to hopefully achieve a number of things. First up is some software tuition with Phil Morrison, looking at analysing and optimising boat stability. That evening we’ll then, all being well, have the dinner with Tim and Debra Searle that was postponed a few weeks back – Tim is one of our carbon fibre experts and Debra rowed the Atlantic solo a few years ago – so it should be interesting and very educational!
All the best,
Mike
