1977-2000 Suzuki DT5/6/8 Outboards Service Manual, Page 96Get this manual
PROPELLER CONSIDERATION OF TRANSOM
(1) Rough waters
The DT55W8 outboard motors availabIe for two transom sizes, (15in and (20inSelect the outboard motor to suit the boat, that is, to meet this requirement: Locate the cavitation plate 30 to 50 (1.2 to 2.0 in (standard) below the bottom of the boat
Cavitation
boat whose bottom is such as to promote "cavitation"long-keeled boat is such one