Saturday, 26 January 2008
Of jibs and drogues
I’ve had a brief affair with a small jib. With a suitable triangle of Dacron in the cupboard I couldn’t resist trying it out. I stepped the mast in the aftermost position and rigged the jib from a pulley at the masthead to the deadeye on the stem. I lead the sheet back to the cockpit and tied it off with a clove hitch on the thole pin.The headsail worked after a fashion; while it was too small really to pull I found that in light airs it did make half a knot’s difference to our speed. I didn’t, however, notice any significant change in pointing ability. In stronger winds, although I banged tension on the halyard, the luff was unstable. The sail thrummed and hummed and wouldn’t settle. In the end I struck it and undertook the tricky operation of changing the mast position at sea.
The original idea behind the jib was to move the centre of effort slightly further forward to achieve a tad more lee helm with the mainsail, which could be compensated by sheeting in the mizzen more tightly. However, the reason that more lee helm seemed desirable was because I was sailing OB with the rudder raised. Having given up this practice in favour of the more conventional method of tying off the rudder amidships I’ve obviated the need for more lee helm.
Onawind Blue sails herself fine like this though she is slightly more inclined gradually to change course. I think this tendency can be eradicated by finding a better method of tying off the rudder.
I’m afraid it all sounds impossibly technical—I perceived a need for a jib due to a technique that I was using. But changing the method rather than the sail plan proved the more effective solution.
What this incursion into rig dynamics has made plain is that OB is still under canvassed. She’s about 25 sq ft short of the prescribed amount. This extra sailcloth, which represents 20% of the total area, will make her far zippier in light airs and faster still when the breeze is up. Getting a set of the right sized sails has moved up my list of things to do.
Now I still have a useful triangular piece of sailcloth in the form of my ex-headsail. I’ve tried rigging it as an awning and it works although it is rather slim for decent shade. Ideally, if it’s to stay on the boat, it should perform two functions so I’ve thought about attaching the luff to the leach and thus making an open ended cone which can be used as a drogue.
Drogues look like windsocks. Used in extreme conditions they are deployed via a long rode from the stern of a boat to slow it when running downwind under bare poles and thus lessen the dangers of broaching and capsize. I don’t think I’ll be doing much running downwind under bare poles but a drogue may be very useful for returning to the beach in the, not uncommon, event of the waves having increased while I’m out sailing. Rowing towards the shore through breakers, a drogue should slow us at that critical moment when OB starts to surf and a broach and capsize become imminent possibilities. Although I have gained practice at returning to the beach through waves and can control the boat with a degree of confidence, I’m all too aware that there are waves over a certain height that ice my stomach and dry my throat.