Re-inventing the wheel

Looking at the new Harken Pro-trim traveller system

Re-inventing the wheel is not that common onboard race boats, but you could argue that Diverse Yachts' Lou Varney has done just that. Diverse are a specialist electronics and hardware distributor in the UK and Varney has worked closely with the engineers at Harken to come up with what is now called the Harken Pro-trim system.

In the first instance this new mechanism has been developed for mainsheet travellers but Varney is keen to point out that the philosophy and engineering behind could easily be adapted for other high load lines where you want to get rid of the existing block and tackle control.

The Pro-trim has been through two major life stages - an early prototype which use the big wheel/little wheel principle to a system which cleverly incorporated gearing for the power.

"This all came about because I am a very lazy mainsheet trimmer," Varney jokes, "and I decided that I needed some means of pulling the traveller up and down on many boats that don’t ever have enough purchase.

"So often you get on boats and you do not have enough grunt - especially on those boats that have a lot more interior. You have no way of cascading blocks and putting lots of purchase inside the boat so there was definitely a need to find a way to up with a system that generated power for us by hand."

The prototype was tried on the successful Mills 40 Tiamat with a big wheel driving a much smaller wheel - with this difference in size delivering the purchase power. At this point the idea using a Code Zero furling drum as the big wheel came to the fore - it gripped the rope well and enabled the whole control end to be continuous, eliminating line from the deck.

"It kind of worked, but it wasn’t brilliant," comments Varney. "So then I thought we better get the Harken engineers involved with it!"

They took it on and came up with a way of putting gears into it - so not just relying on the bigger wheel, and with the power coming from the gears. The benefits were also a much more compact system, with the control end in one place by the mainsheet trimmer and the mechanical 'guts' located underneath the traveller itself.



The lines that come off the traveller go underneath the deck and go onto its own single little drum for each side. The two are driven together so that as one drum loads the other un-loads. This means that there is no line hanging about and reduces the risk of line tangles and cascades of block jamming up.

The first full scale system was fitted to the Rogers 46 Danebury Vineyards which Varney says works "very, very, well."

For the mainsheet trimmer says Varney; "the beauty of this system is that it is always clean on deck - and you don’t have loads of line. And you can build as much power into the system as you want really." This can be done by simply altering the gearing of the mechanism.

Varney explains how he has got used to it sailing: "When you are sailing upwind and you want to dump the traveller a little quicker, you can give it a little jerk and this drum will free run - which will mean that the traveller will just run down and then you just check it and then it grips back into the control wheel. So you have a good means of dumping a lot of traveller very quickly.

"When you are tacking it is so easy. You have one line in one hand and you just go straight across with it. You are always trying to get the car into the position you want it to be, with this you can control it much better and get the car straight where you want after the tack. Then you can cleat it and fully concentrate on the mainsheet."

Currently the plan is to fit the system to Colm Barrington's Magic Glove in time for Key West. "That's a 50 footer with lots of sail area and it really has no room downstairs to put any purchase system," says Varney. The new TP52 Patches is a confirmed order and discussions are ongoing with other TP52 campaigns.

There is an obvious comparison of the weight of the system compared to blocks and rope in a purchase system. Varney says that the drive shaft will come in carbon and the couplings be made out of aluminium thus reducing the overall weight. It looks right for boats with twin wheels - with the shaft running underneath the cockpit between them - but it could also be used with boats with a single through-deck wheel with the shaft mounted down by the hull.

The system can be designed-in at the start of a new build, or can be retro-fitted - especially if you have a main sheet trimmer who grumbles a lot about the amount of furniture downstairs…