24 One-Design Class Sailboat Handbook 



has a tendency to pound or bounce. Actually, its major virtue is ease of 

 construction, particularly if the bottom is planked athwartships rather 

 than fore-and-aft. With the exception of the modified flat-bottom— which 

 can be identified by the abnormal flare of the sides— this type of hull 

 has few good sailing virtues. 



The V-bottom hull avoids most of the difficulties of the flat-bottomed 

 hull. It is stable, seaworthy and has good speed. Actually, this type is best 

 for the beginner. 



The round-bottomed hull is the strongest and lends itself to a better 

 appearance. Under normal conditions, it doesn't have quite as much 

 stability as a V-bottom hull. It may not be able to carry as much sail 

 without heeling objectionably, but its stability can be increased by proper 

 use of ballast, less sail or by greater skill on the part of the skipper. This 

 type of hull is fast, but there's no proof that it's really faster than the V- 

 bottomed in small-sized sailboats. 



The arc-bottom is fairly uncommon, except in the Comet, Lightning 

 and Star classes. In all basic elements it is similar to the V-bottom and its 

 characteristics are also similar. But this type of hull is more expensive to 

 construct. 



In addition to the standard type of hulls, there are two other one-design 

 class shapes that should be mentioned. They're the scows and multishapes 

 such as catamarans. Scows are beamy, slightly round bottomed, extremely 

 shallow-draft or "skimming-dish" type sailboats and are of light con- 

 struction. This type of hull is most suitable for protected waters such as 

 lakes or bays. Catamarans are fully described in Chapter 8. 



As is discussed in the rating of sailboats for handicapped racing in 

 Chapter 5, the longer the boat and the more sail area it flies, the faster 

 it goes. But while a small boat may not in actual fact go as fast as a larger 

 craft, it seems to go a great deal faster since the occupants are much 

 nearer to the water. In many cases it can go faster for its length than a 

 larger boat. This is because many of the modem craft are able to plane. 

 Planing happens when the bow waves become sufficiently strong to lift 

 the fore part of the boat right out of the water. When this occurs the 

 wetted area of the hull is drastically reduced and with it the friction that 

 holds the boat back. The result is an increase in speed. 



Keel boats, which use a fixed ballast, are seldom able to plane because 



