The Offshore Voyaging Reference Site

Sail Area: How Much and How to Distribute It

How Much Sail?

Question: How much sail area do you think an offshore boat should have for a given weight?

Answer: Our boat, Morgan’s Cloud, has a comparatively high sail area displacement ratio for her type, of 16.5. This combined with good sails and her very easily driven hull shape means that we can sail in quite light airs without resorting to substantially overlapping sails. I think that cruising boats should have as tall a mast as possible, within reason, without compromising stability. High aspect ratio foresails are easier to handle and roller reef better. Propper sail area makes for faster passages and the shorter the time you are at sea, the less chance of severe weather.

How to Distribute Sail Area

Question: What is your thinking on how sail area should be positioned between the fore triangle and mainsail on short handed cruising boats?

Answer: I think there are two ways to go: The first is to have a big mainsail and a small fore triangle so that the jibs are small, and to be a sloop. The second is to have a bigger fore triangle and be a true cutter—one that carries the staysail all the time with a jib topsail (Yankee). I think that the first is better for inshore sailing since the boat is easily tacked but the second is better for offshore since, particularly if both staysail and jib topsail are on roller furlers, it gives more flexibility.

Morgan’s Cloud is a cutter with a large fore triangle. Her relatively tall mast and large sail plan allow her to sail well in as little as 6 to 8 knots of apparent wind and we can go all the way to heaved-to in gale force winds without making any sail changes using our two foresails on roller furlers and 3 deep reefs in the main.

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