differences racing & cruising sails
I am doing a project on the difference between racing & cruising sails ,
I already found a lot of usefull information but I could still use some help.
Does anyone knows the differences in the shapes of racing mainsails,spinnakkers?
Also in according to aerodynamics.
From what I've seen, the aerodynamics of cruising and racing sails are basically the same. The differences concern durability, ease of handling, and cost. These are largely driven by the materials, not the shape. Where you do see differences in shape, they are also driven by these factors. For example, a smaller roach with polyester vs a large roach or square-head main with a material that can take the greater leech loads.
For example, a cruiser may opt for a masthead cutter rig with a stiff mast and fixed backstay that allows one to fly a roller-furling genoa, a staysail on the inner forestay, and has a smaller mainsail. A racer may opt for a fractional rig with a bendy mast and running backstays to control luff tension, large main, and an extensive sail inventory to match the conditions. The cruiser doesn't have to worry about handling runners on tacks or risking the rig in an accidental gybe. The stiff mast is also more rugged and the inner forestay prevents the mast from inverting when the mainsail is reefed. The smaller main is also easier to raise and to reef.
Cruisers will opt for some sail combinations, such as twin headsails for running downwind, that make for easy handling but sacrifice too much performance for the racer. Cruisers will also use rigs that break the sail area into more manageable pieces, like ketch and yawl rigs. Again, the motivation is handling but the shapes of the sails will be the same within the limitations of the materials.
The racer will also use exotic materials with a high elastic modulus to ensure the sail retains its shape over a wide wind range, but the sail will only retain its racing shape for a few seasons. The cruiser will tolerate a wider range of sail shapes (because the performance is good enough instead of the best) and will use a lower modulus material, such as polyester, and in a heavier weight to achieve durability that will last for years. However, some modern materials, such as spectra, are also finding increased popularity with cruisers when they offer durability (spectra has the best UV resistance among the modern fibers), the cost is reasonable. These modern materials allow the sail to be lighter and thus easier to handle.
Some racing innovations, like fully battened mainsails, have also found a home with cruisers because the fully battened main doesn't flog when the sail is luffed, and it flakes well on the boom. In addition to improving the performance.
Cruisers also picked up on asymmetrical spinnakers because they are easier to handle in some ways than a symmetrical spinnaker. Even for a symmetrical spinnaker, I think the difference between a cruising spinnaker and a racer's will be more in the size rather than the shape, with the cruiser opting for a smaller sail to make it easier to handle.
And some cruising innovations have been adopted by racers, such as roller furling headsails, and cantilevered masts with wishbone booms. The bring the ease of handling to race boats with shorthanded crews.
Bottom line is, for a cruiser it's not all about aerodynamics but for a racer, it is.
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