On Mon, 15 Dec 2003 14:24:24 -0000, "garry crothers"
wrote:


"Meindert Sprang" wrote in message
...
"garry crothers" wrote in message
...
Excuse my ignorance, but how can I tell if the cylinder is double action
or
single. I've just looked at the Vetus catalogue and cant see any
reference
to single or double?

I think all Vetus cylinders are double action. If you see one hose nipple
on
each end of the cylinder, they definately are.

Besides, I fail to see how two rams can prevent any twist anywhere in the
rudder system.

Meindert

I believe that the advantage with two rams is that, because one cylinder
pushes aft, while the other pulls forward with the same force, the only
force on the rudder stock is the desired twisting, and no side loading is
imposed, as the case would be with the use of a single cylinder.

But then again I am no expert,

garry

Quite! :-) (no offence)

Brian W