Page 11 - NAVAL FORCES 03/2017

T echnology Spotlight

The most radical hull in current service is the trimaran,
here typified by USS “Tulsa,” being prepared for launch.
(All photos via author)

Norman Friedman

Unconventional Hull Forms

Nearly every surface warship in the The main non-landing craft survivors of The main current candidates to replace
world has the same sort of hull: A air-cushion hulls as replacements are the conventional hulls are trimarans (like the
displacement hull, long and slender if Norwegian “Skjold” class missile boats “Independence” class), semi-planing hulls
it is to be fast, beamier if it requires and mine countermeasures craft. Similarly, (like the “Freedom” class), and wave- piercing
great hopes were once held out for hydro-
hulls (like the “Zumwalt” class and the planned
greater steadiness. From time to time foils, particularly those with submerged foils French frigates). All these alternatives are re-
radical alternatives are tried. A few and consequently better sea-keeping charac- sponses to the inherent limitations of conven-
decades ago, it seemed that various teristics. For example, at one time it seemed tional hulls; in each case the great question is
kinds of air- cushion hulls that the US Navy (USN) would whether the price paid for an unconventional
might replace conventional build as many as 30 “Pegasus” class hull buys enough advantages to be worth the
ones, not only for landing (Author Photo) missile hydro foils. They proved trouble. Unconventional hull forms are typi-
craft (many of which use extremely expensive to operate, and cally proposed to solve one (or more) of three
inherent problems: Speed, steadiness (e.g.,
no one wanted to buy them when
them) but also for larger the USN prematurely retired the six to operate a helicopter), or ship motion in a
ships, such as corvettes and it built. seaway. The problem is generally the way in
frigates. A detailed look at
unconventional hull forms. Dr. Norman Friedman
is a regular contributor to NAVAL FORCES.

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