Service manual

GENERAL INFORMATION

SERVICE MANUAL NUMBER 26

90-861329--1 MARCH 1999 Page 1A-7

For best speed and minimum spray, the corner between the bottom and the transom should

be sharp.

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a-Bottom

b-Corner

c-Transom

The bottom is referred to as having a “hook” if it is concave in the fore-and-aft direction. A

hook causes more lift on the bottom near the transom and forces the bow to drop. This

increases wetted surface and reduces boat speed. A hook, however, aids in planing and

reduces any porpoising (rhythmical bouncing) tendency. A slight hook is often built in by the

manufacturer. A hook also can be caused by incorrect trailering or storing the boat with

support directly under the transom.

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a-Hook

A “rocker” is the reverse of a hook. The bottom is convex or bulged in the fore-and-aft direc-

tion. It can cause the boat to porpoise.

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a-Rocker

Any hook, rocker or surface roughness on the bottom, particularly in the all-important

center-aft portion will have a negative effect on speed, often several miles per hour on a fast

boat.

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