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Hi, Cliff - a late response to your query (haven't
checked my emails for a long while) but here goes: the short answer is yes, the
submarine will generally roll into a dive. You
are absolutely correct. Centripetal forces though? The
relationship of forces is mostly between hydrodynamics (water
resistance) and moment arms (mass, applied energy and vectors).
Now, a weasel word here: AMOUNT OF ROLL
DEPENDS . . . on the hull shape (sideways slippage or sidle), the distance
between the sail and the rudder (vertical difference along the Z-axis, a moment
arm), distance between the sail and the rudder (longitudinally or along
the X-axis, another moment arm), the differences in area between the rudder
and the sail (a function of hydrodynamic resistance), how much keel ballast
is aboard (mass and moment arm in roll), how low the ballast is installed
relative to the sail (another Z-axis moment arm or centre of gravity), and
the amount and duration of the forces applied by the propeller (surge
forces) and rudder (yaw forces). Whew!
(ref.: http://www.psubs.org/pic/moment.html
- the bottom diagram shows the degrees of movement)
Jeepers, is this helping or hindering . .
.
I won't bore you with all the
permutations. Simply, if the sail is large (high surface
area) and the rudder hard over, the boat will roll faster at high speed
than it would if the forces applied were minimal (say at 1/2 a knot
forward speed). When the boat rolls, IT DOES CHANGE THE ANGLE OF THE
RUDDER. The rudder is still moving the boat sideways but in a different
plane, just like an airplane. The airplane does have slightly different
forces acting on it mind you, but, most of the elements are there. A
submarine is more like a blimp than a plane in some respects.
When the rudder first moved it was vertical.
The stern slipped sideways in the water (like a speedboat's) but the SAIL IS
BLOCKED BY WATER and can't move sideways. Hull goes left, sail stays
put. This is like a huge hand pushing the sail over to the right. Is
the rudder still vertical? Nope! Now it's at an angle aiming the
boat downwards. It's easier to visualise if you have a model sub in your
hand.
And, yes, apparently the Albacore did indeed have
roll issues, mainly because of its high speed capabilities, large sail
and tapered stern. More forces.
Hope this overdue answer helps.
Warm regards,
Rick Lucertini
Vancouver, Canada
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