Dr Harken introduces towing genoa cars, proper cockpit sail trim
by Hannah Cotterell, Harken UK 24 Apr 2015 11:19 BST
24 April 2015
Dr. Harken © Harken UK
Putting your genoa car in the right place
In the days since the furling and reefing genoa came into popular use, there has been a general drop off in good sail trim on cruising boats. It is easy to change the size of your jib without leaving the cockpit. This has led to these systems being almost ubiquitous on any modern cruising and, to a growing extent, racing boat - and quite right too! However, the reluctance (on good safety and comfort grounds) to leave the cockpit often leaves the genoa lead car in the wrong place on the track, resulting in a poor sail shape, lack of power, flogging leeches, causing damage to the sail and reduced capability for sailing upwind, none of which is remotely desirable.
The answer comes in two parts: Firstly, knowing where the car SHOULD be, and secondly moving it there. Of course, being able to move the car easily makes the first task easier to accomplish!
The best solution by far is towing genoa cars that run on ball bearing tracks. This will enable you to move the car, and see the effect on the trim-all under full sheet load and from the comfort and safety of the cockpit.
Challenges when moving your genoa car
The challenges start when we look at the tracks we have in place today-usually T-Track with the cars secured by pinstops into the hole in the track. Once the sheet load is on, there is enormous friction between car and track. Pulling it forward under load is impossible and any attempt to do so will usually result in damage to the car, the track, the towing system or you-sometimes all of these. It is possible to tow on T-Track, but you will need to unload the sheet first by tacking, luffing, easing the sheet, or by furling the sail up. You can then move the car and put the load back on. This is not the most convenient of methods, but it will work.
If you are lucky, you might have tracks that are ready for ball bearing cars. If not, to get the full benefit you will need to change the tracks. This can be a rather daunting prospect-headlining down, removing the old track (depending on how it is attached this might mean grinding or unbolting or unscrewing from tapped plates in the deck), finding a track with the same pitch and size for the fasteners as the existing track, making good and redrilling if that is not possible. The fun is almost without end. You might consider giving this task to your boatyard.
Installing a towing arrangement
Once you've got the tracks right, you need to install a towing arrangement. The car will normally have a sheave or two on the front and you can add an end control to the front of the track, then it is simply a question of reeving the purchase and leading the towing line back to the cockpit and securing it. On smaller boats a cleat is appropriate. As you get larger, a clutch is probably more appropriate.
While we are on the subject of towing line loads, the steeper the sheet goes up from the car to the clew, the higher the load will be on the line. A modern high clewed purpose built furling headsail will present something like a 45 degree angle - the towing line will see about 30% of the sheet load. On a typical No 3 blade jib the towing line might well see more than half of the sheet load. For this reason, if you are going to be using a blade jib you might want to consider a separate car for the purpose with either a much higher purchase OR pin-stopped in position.
Once your towing genoa car is installed...
Once your system is installed, it's time to go sailing. and Let's get the system set up. Your furling genoa might well have calibration marks on the foot so that you know how much sail you have reefed. It makes sense to get the car in the right place for unreefed sailing and take a note of the car position or, better yet, mark the position. Then reef to the first calibration mark, move the car to the best position and again mark or note the position. Do this for all the calibration marks and you will have a great starting point when you are sailing normally. Reefing is suddenly quick and easy and you will sail with the correct sail area, properly trimmed-worth any amount of challenging fitting surely?
That's all for now...
Dr.Harken!
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