Tuesday 14 April 2015

New Mainsail

Hi everyone,
With the Galley Makeover set of blogs complete I can now describe other work.  The other big expense we've been looking into has been a new mainsail.  We are very happy with the yankee headsail made for us by Extreme Sails in December last year.  We decided to have Dubbo and Carl make us a new main.  Like the headsail it will be constructed from 8 oz cruising laminate.

New mainsail under construction
Our old mainsail is approaching 10 years old.  It is a very nice sail built by Hood and with an area of about 28.5 sqm.  Other than its age it has one major flaw - only two conventionally sized reefs.  We eventually decided that our cruising plans demand a main which can be reefed down to trisail size.  Since the boat is setup for two reefs we knew we wanted two reefs in the new sail - but very deep ones.

Initially the concept was to have a conventionally cut sail with less than full hoist.  The full new sail would have the area of the old sail with one reef - about 24.5 sqm.  Its first reef would be equivalent to double-reefed and its second equivalent to triple-reefed.  This would have worked but would have left us underpowered in light airs.

With a bit more thought we realised that with less than full hoist we could add additional roach to the sail.  This recovered most of the area lost with a shorter luff and conventional roach, giving us 26.5 sqm.  So with the extra roach the new sail will only be have 2 sqm less than the old, but will have the deep reefs we need.

Full size sail with extra roach
Double-reefed to trisail size
The new sail will have full-length battens like the old sail.  However it will have slugs with rollers to reduce friction when hoisting and lowering.  The rollers run up the aft face of the mast, which is happily suitably flat!

Roller Slugs
The sail's leach cord will run from the clew to the head and down the luff, allowing adjustment at the tack.  Much better than trying to adjust it at the clew.

It will be interesting to see how the boat performs with the new sail.  The centre of effort will be lower, reducing healing moment.  The centre of effort will also be further aft, increasing weather helm.  She has always had minimal weather helm when beating, particularly in light airs.  A little more may well be an improvement.

Looking forward to receiving the new sail in a few days.

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