U. S. Coast Guard Island Class 110 WPB PDF Download

Author: Dominic S. Cusanelli
Publisher:
ISBN: 9781423540908
Category :
Languages : en
Pages : 100

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Book Description
Model experiments were performed to evaluate the performance of a stern flap on a U.S. Coast Guard Island Class 110 WPB patrol boat. Several stern flap designs of various chord lengths, spans, and angles were evaluated. The selected stern flap design was based upon maximizing power reduction at high speed, while satisfying secondary powering criteria prescribed at cruising speed and best economic speed, and limits set on desired running trim angle. A stern flap with chord length 2 ft. (0.61 m), span of 8.7 ft. (2.7 m), and an angle of 7.5 degrees trailing edge down, is recommended for installation on the Island Class. At full load, with the stern flap installed, the maximum attainable speed will increase by 0.8 knots. The stern flap maximum power reduction of 5.8 percent was attained at 16 knots. This 5.8% powering reduction includes an empirical 1.5% reduction for stern flap scaling effects as determined from tests on other ship models. Stern flap annual fuel savings for the Island Class is estimated at more than 13,000 gallons/year. The time to recover the estimated cost for stern flap fabrication and installation is less than one year. It is recommended that bow spray rails also be installed in the Island Class. The bow spray rails affected a significant reduction in the amount of spray and forward deck-wetting generated at the bow. A new DTMB Model 5526 was constructed for this project. A ship/model correlation allowance of CA = 0.0003 was estimated from a powering comparison between BAINBRIDGE ISLAND (WPB 1343) and Model 5526.