Jasen Betts wrote:
On 2005-12-09, Dave Baker wrote:


The real issue is
compliance to local law. Or in other words, how do you secure a border
and monitor vessel movement?

Not so easy in developing countries with scarce enforcement resources.


So my third question now is......How much do you have to spend?

Me? None! :-)

The client - not sure. They want us to include an option for detecting catch
amounts with our tracking system. If it's within their (unknown) budget, then
they will hopefully take the option. Presumably if they are at all interested
we will have to do some trials first.


You may be able to measure how much the have in their hold by measuring the
displacement - IE depth - IE water pressure at a underwater point on the hull.


You might need to compensate for fuel load and, for the suspicious,
ballast tankage. A long term average might actually compensate for
heave, etc.


if you can measure torque or RPM on the propshaft or turbulence near the
propellor that measure combined with speed (calculated from GPS readings)
would give some indication wether they were towing anything.

And displacement vs drag vs speed vs fuel flow vs windage might help
refine the reading. But still, you got bycatch to worry about, eh,
and disposable anchor blocks, what else?

Sounds pretty invasive to me. Pretty vulnerable to cheating, too.

Terry K


another point to meter would be the operation of the winch motor or mechanism.








Dave