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Re: [PSUBS-MAILIST] Submerged speed calc



A couple of years ago Peter Madsen wrote about Kraka and her snorkeling performance.  His comments:

...the primery problem that hits a classic shape during high underwater speed is a "nose up" tendency. Kraka has a hull that has this tendency since most of the drag inducing superstructure is above the center of thrust, causing a rising torque as uw speed increases. At some 6 knots the boat ( expected ) goes out control, since at this speed the dive planes are 15 degrees down - yet the boat still rises. That is the limit of the design.

Great that Kraka just rises for him when going out of control.  At the time he seemed to really like running on snorkel and was getting into work on his UC3 boat which has a modern shape more optimized for submerged speed.   http://www.bluesky-services.dk/submarine/pages/page_050_uk.html


take care-
Paul