Building Tarka II (Part 1)

After the model testing, we were pretty happy with the design. Now its time to start building the real thing!

We got the frames water jet cut in Portsmouth. These were then screwed to our extremely sturdy and perfectly level eleven legged table - that got some funny looks in Ikea, I can tell you! Stringers were then fitted into recesses in the frame to form the shape of the hull!


We tapped up all of the frame with parcel tape - fingers crossed this will help release the boat from the frames when it is complete!

We next added core cell foam to the frame work which is very stiff until you heat it up. When it is warm, it is flexible and allows easy forming over the frames. This allows us to get a nice smooth shape that we can later bond the carbon fibre to!



Coming soon... Carbon Fibre photos and timelapse of the build so far!

Tank Testing (Take 2)

Time for the second set of tank testing. This time with the new hull! Same tank as last time (Solent Uni) but this time with a bigger model. We went for a 1/3 scale model instead of the 1/4 scale that we used last time to give us more weight to play with. Last time it was very difficult to do everything with 200 grams of ballast weight, this time we have 2.5 kilos to move about!


This was one of the endurance runs. You can see the trim has been adjusted to get the bow in the water and the transom just out of the water. This gives the lowest resistance at the stern of the boat and only slightly increase wave making resistance (energy used to make the wake). This looks like it could be a winning design for the endurance race...


This is a sprint run. So shouldn't the bow be out of the water? Well no. The model was fitted with an interceptor (a trim control device) to keep the trim flat and reduce resistance - you can see the spray from the interceptor at the stern! Amazing what 5 millimetres of vertical planking at the stern can do!

Model Building Tarka II

The model for Tarka II was built in pretty much the same way as Tarka I, using frames and strip wood planking. I won't bore you with details again, but here are some pictures of the model in build.

Tank Testing (Take 1)

Its taken weeks of standing out in the freezing garage superglueing our fingers to thin plywood strips. We've gone through several trees and an entire beach worth of sand paper, but the model is finally ready.

Today we took it down to the towing tank at Southampton Solent University. Their tank is 60 meters long and allowed us to test (at an equivelent speed of 17 knots).

The model is fixed to a carriage that sits on rails via a post. The carriage can then be sent down the tank at precise speeds and the resistance of the model can be measured.



The model is sent down at a series of speeds, correcting the trim each run and then a resistance curve can be produced which will give the naked hull resistance of the boat at any speed. We can use this to estimate the amount of power required to reach certain speeds.

We ran tests in the sprint and endurance conditions and the data should prove invaluable to help us design the new boat.

Model Building Tarka I

We have been set the challenge of redesigning the hull for Team Tarka. The rules of the competition mean that the hull must be optimised to fit somewhere between being really efficient at low speeds (for the endurance event) and being really efficient at high speeds (sprint event). These two cases require a hullform with completely different features.

Before we start designing the new boat, we need to get a better idea of the performance of last years boat. We want to get some accurate data from some towing tank tests.

To do this, first we need to build a completely accurate scale model of last years hull.

We started by getting some frames (bulkheads) laser cut from 4mm thick marine grade plywood. These form the basis of the model and ensure that the shape of the hull is accurate.

The next challenge was to glue even thinner plywood (1.8mm) to the frames to form the hull of the boat. This took a suprising amount of time! Once the strips were glued on, they were faired - so much sanding...

The finished hull was then ready for a thin layer of GRP and painting - more sanding!

The boat then went on a major weight loss regime, losing most of the longitudinal (fore-aft) structure and all the bulkheads were cut down.

Team Tarka 2010 first meeting

After the long summer, team Tarka reconvened today to begin planning for the 2010 competition. Early days yet, but we have new people on board, a new team captain, Jon Burton, and much stronger links to the ship science group. It should be an exciting year ahead.

First date for the diary is the 20th October, when last year's team will give a talk at the IEEE student branch. See the IEEE site for more information.

Team Tarka featured on Eland "Reel Life" blog

Eland cables have added an entry to their reel life blog about team tarka, and the important part that Eland played in getting our boat ready for the competition.