There is a lot of wisdom in what Mike writes and refers to. The soft chine hulls are less effecient at planing speeds--and there are "kits" added to some larger Bayliners which have soft chines to increase their speed, effeciency on a plane and stability at higher speeds--but there is a loss of sea keeping ability.
There was a fleet of water taxies in Los Angeles for many years, which were 40 to 45 feet long and were soft chine boats but ran at 12 to 15 knots. The bottom profile was similar to a Down East/Lobsterman type of boat.
The Down East boats are a compromise of effeciency at a plane/semi displacment speed and sea kindliness of a soft chine--but flat bottom. You cannot divorce the chine shape from the entire hull shape. But a down east type of boat would not be necessarilly a good passagemaker.
The soft chine hull is more effecient at displacement speeds. Some hard chine hull forms, such as a semi dory (have a narrow beam water line) are effecient handle well and track well at semi displacement speeds.
The problem with any short keel, is that the boat can pivot or trip on that short keel. The longer keel helps to prevent this, as the boat accelorates going down the face of a wave.
If you are making coastal passages, perhaps a semidisplacement boat would make some sense--but for ocean crossings, a full displacement hull would be more effecient and seaworthy.
Bob Austin
There is a lot of wisdom in what Mike writes and refers to. The soft chine hulls are less effecient at planing speeds--and there are "kits" added to some larger Bayliners which have soft chines to increase their speed, effeciency on a plane and stability at higher speeds--but there is a loss of sea keeping ability.
There was a fleet of water taxies in Los Angeles for many years, which were 40 to 45 feet long and were soft chine boats but ran at 12 to 15 knots. The bottom profile was similar to a Down East/Lobsterman type of boat.
The Down East boats are a compromise of effeciency at a plane/semi displacment speed and sea kindliness of a soft chine--but flat bottom. You cannot divorce the chine shape from the entire hull shape. But a down east type of boat would not be necessarilly a good passagemaker.
The soft chine hull is more effecient at displacement speeds. Some hard chine hull forms, such as a semi dory (have a narrow beam water line) are effecient handle well and track well at semi displacement speeds.
The problem with any short keel, is that the boat can pivot or trip on that short keel. The longer keel helps to prevent this, as the boat accelorates going down the face of a wave.
If you are making coastal passages, perhaps a semidisplacement boat would make some sense--but for ocean crossings, a full displacement hull would be more effecient and seaworthy.
Bob Austin
