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Originally Posted by FERdeBOER
The sail is needed. Not only for placing sensors, but because without it, the sub would rotate on its longitudinal axis without control.
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Um.. no. The metacentric height would prevent that. The center of gravity is below the center of bouyancy then ensuring a righting movement that would keep the top side UP.
When a sub is at PD it tends rock due to the forces acting on the vertical sail surface. Actually, I believe that a sub without a sail would be more stable at PD as the rounded surface would not be as effected by wave action.
But....
One reason for the sail is that the boat can be deeper and still pierce the surface interface. Thus the boat is less affected by wave action and surface tension/ducting.. If you place these masts and sensors in the hull, you have to have a MUCH longer mast, which will vibrate as it travels thru the water. Since you are talking a long, fairly stiff shaft, this means that you will have low frequency harmonics which travel better in the water. Also, you will be REALLY speed limited with this extra long mast supported from just one end. If you make the masts short so that these are not issues, then think of how close to the surface you will have to be. It would mean that anything over a state 2 or so sea would be impossible due to wave action.