Lighter Winds Cont.

Where Next?
Bob Williams
Mon 8 Feb 2016 21:35
Noon Position: 18 53.5 N 122 26.8 W
Course: West Speed: 2 knots
Wind: North nor' east, F2 light breeze
Sea: slight Swell: north nor' east 1 meter
Weather: overcast, mild
Day's run: 94 nm

Another day of light winds, in fact lighter winds, and slower progress, but at least we continue to make progress. The reason I have biased my course to the south of the rhumb line route to Hawaii is to skirt around the North Pacific high and to get into the north-east trade wind belt, but at this time of year Hawaii lies to the north of the trades, so it is a matter of striking a balance between distance sailed and finding some wind. The great circle route would have taken us even further north into the NP high's light and variable winds. It will be interesting to catch up with Harald in Hawaii to compare notes. He left San Francisco about a week before I left Mexico (in hind sight I should have done the same as him).
With light winds comes the problem of sails slatting, in particular the fully battened main. Full battens are excellent for better sail shape and easier sail handling under most conditions, but in light winds the tension in the battens cause the sail to act like a wobble board, and the energy stored in the tensioned battens is increased and released each time the sail 'wobbles', which, depending on how much tension is in the battens, can be quite a bit. In light winds I have worked out that some of the tension can be reduced by loosening the main halyard a little as well as topping up on the boom topping lift, which reduces the tension on the luff and the leech of the mainsail respectively, allowing the sail to act more like a sack of cloth, rather than a stiff board.
Despite these adjustments, come one o'clock in the morning the mainsail's crashing had become more than I could stand, so I dropped the main and raised the drifter in its place, sheeting it out through a block in the end of the boom, then guying the boom out so as to maximise the amount of sail presented to the light airs.
This morning the wind has freshened a little (I suspect a diurnal variation due to the diurnal variation in the earth's atmospheric pressure – a tidal effect I believe, but one that I confess as yet I do not understand) and backed a point* or two into the north. The mainsail is back up and the jib is down. We beam reach with a hiss from astern and a gurgle ahead. I use the fair weather to do a few small projects, namely sanding back and varnishing the timber trim over the rear of the dodger, and attending to some minor but unsightly rust between steel and timber work around the companionway.
All is well.

* A point is 11.25 degrees, or 1/32 of a circle, and while 11.25 degrees sounds awkward, a point is in fact a very natural measurement arrived at by the traditional method of halves, and is aligned with the traditional cardinal points of a compass, eg North by East is 011.25 degrees.