Bouwe Bekking explains why Team movistar has switched hydraulic keel rams 31/1/06

Bouwe Bekking explains the reasons why the VOR movistar team decided to take drastic action and replace new titanium canting keel hydraulics with the original stainless steel ones.

According to Bekking they are in no doubt that it’s the right decision. The titanium rams have caused nothing but trouble since the early part of Leg 2 whereas the stainless steel ones that the team used for 20,000-mile training period prior to the start of the VOR in Vigo gave no problems whatsoever.

So why did Team movistar switch rams just before the start? Pedros Campos, team manager explained: “?it was a simple search for more speed, another turn of the screw for the boat’s performance, but we now know that we were not forced to make the decision as everyone was pushing the limits.”

By using the titanium rams the team was able to save over 100 kilos of weight. Which, as Olympic gold medallist Xabi Fernandez explained: “those weigh saving kilos can be diverted to the bulb and stay below the minimum authorised weight; the heavier the bulb, the more sail area you can deploy and the faster the boat goes.”

But why did the titanium rams fail? Greg Waters, expert in hydraulic systems
for canting keels working for a specialist company Central Coast explained: “The hydraulics have failed us because they are made from titanium; it is a very valid material. The problem arose because they were too light, even for titanium. In my opinion, they should have been about 50 per cent heavier, and even then, they would have saved a lot of weight in comparison with the ones we are going to mount now. Titanium has peculiarities that have to be taken into account when working with it, and it is better to make them a bit heavy rather than the ideal weight.”

Central Coast mounted the hydraulics on movistar on its initial crossing from Australia to Spain. Waters continued: “Initially, the idea was to mount carbon hydraulics. While the team was waiting for them to be ready, we made the stainless steel ones, which were the hydraulics used by the boat, without incident, when it sailed from Newcastle (Australia) to Vigo. The carbon ones were mounted in Sanxenxo and they scarcely lasted 20 minutes, so we went back to the stainless steel ones. We were later asked to make a second steel set, just in case they were needed, and just a few weeks before the start, the team opted for the titanium ones, which we do not manufacture.”

The hydraulics work all the time the boat is sailing – in this case over 470 hours on the second leg of the Volvo Ocean Race – even when the keel remains in a set position. According to Team movistar the titanium ones used to reach Melbourne could not stand up to the demands of the race from Cape Town. Waters concluded: “Their safety margin was insufficient. This variable measures the number of times that can resist the theoretical pressure they work at, which, under normal sailing conditions is 35 tonnes for each hydraulic arm, 70 tonnes in all. But, on occasions, this figure is exceeded, for example when you fall over a wave, and that is when they are under the most stress. So: the titanium ones had a margin of between 1.5 and 2, while the ones we are going to mount now have a margin of between 5 and 6, so you could say that with the stainless steel hydraulic arms, we will triple the safety margin.

“The only thing we have to change is the system pressure, because as the new hydraulic arms are bigger, they work at a lower pressure than the old ones. Everything else remains unchanged.”