Shock mitigation is a major concern of the military and several alternative technologies are being considered to reduce crew injuries. Many of the technologies currently scheduled for testing by the military, apart from cushions and seats, are not retrofitable, a major consideration for the existing military fleet. And while cushions and seats are retrofitable and are scheduled for testing, they do not reduce shock for crews involved in missions requiring standing positions.
In May 1991, the Combatant Craft Department ("CCD") of the Naval Sea Systems Command ("NAVSEA") Naval Surface Warfare Center Carderock Division Det Norfolk first evaluated the Hydroflight® system as then installed on a 23-foot catamaran. A sample of the video footage obtained from this test is included below. The objective of the test was to determine the rough water operational advantages and/or disadvantages of the 23-foot craft with and without the foil systems installed. In a report produced are the test, the CCD concluded, in general terms, that the Hydroflight® system improved the craft's sea keeping performance in a seaway, reduced vertical accelerations, and allowed the craft to continue operations in rough waters, whereas, without the system the craft was required to slow down.
In a summary of the results of that test, CCD stated in the report the following:
"The performance improvements of the Hydroflight® system decreased pitch by 63% or 17° and vertical acceleration G-loading (shock mitigation) by 58% or 5G at an 83% increase in speed."*
Accordingly, the following recommendations were made in the report:
"The foil system as tested appears to improve craft's performance in a seaway. The foil system prevents the bow from diving in a following sea or pitching in a head sea; reduces the g loading in a beam sea; and finally, increases the craft's speed at the top end. We recommend that the foil system concept be considered for application and evaluation of future U.S. Navy hulls."*
The initial NAVSEA testing during the 1990 to 1994 period confirmed the fuel savings and increased speed and stability at the same power settings for the boat with foils, as opposed to one without the foil system.
* Source of both quotations: NAVSEA Combat SYSENGSTA, Report No. 60-225, entitled "Trial Results of 23 ft. Hydroflight with Foil System."
The new high-performance prototype deep vee craft currently being developed will be ready for Navy testing soon.
| This video provides a dramatic demonstration of the sea trials conducted with HFS-equipped craft. | |
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| Click the control button on the upper left of a player to begin viewing. If play does not begin, try the rewind ("Step Back") button first, followed by the play button. |