If the cylinders are single action each needs to take the full load. If
double acting it gets more complicated both in calculation and
installing. The pulling force is reduced by the area of the rod. For
example a 2" cylinder with a 1" rod will have a pull force about 75% of
the push so you can't quite divide by 2.

garry crothers wrote:

I am do the sums to calculate the required size of hydraulic ram need to
drive a transom hung rudder.

I read somewhere that it is preferable to use two rams (one on each side )
to minimise the amount of twisting forces on a rudder.

If I decide to go for this method, is it acceptable to divide the torque
requirement by two.

I.E
If I need a 90KgM torque to drive the rudder, can I size the rams for 2 x
45, or should I use 2 x 90 ?

garry



--
Glenn Ashmore

I'm building a 45' cutter in strip/composite. Watch my progress (or lack
there of) at: http://www.rutuonline.com
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