Perfectly normal depending on sea state. 16 kn is correct for glassy seas, 12 - 13 is right for heavier seas.
The XXI is faster submerged than surfaced. At every bell, iirc.
The XXI was designed with a whole slough of advancements over previous designs, surfaced speed wasn't one of them.
And, as Fubar mentioned, charging the batteries slows the boat a bit.
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In the month of July of the year 1348, between the feasts of St. Benedict and of St. Swithin,
a strange thing came upon England...
My U297 build thread
Last edited by Osmium Steele; 07-06-11 at 11:11 AM.
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