Traditionally we used to use a running Docking latch and a bullet on our free flying vehicles.
The advantage with this arrangement is that you can lift the vehicle on the tugger attached to your deployment crane.
It is also a certifiable arrangement helps when you claim on insurance if the vehicle is lost.
If you are looking for spares or other similar items try M-ARE in Aberdee, they have lots of second hand ROV stuff.
MaRE contact details
MaRE Trans. Ltd.
Aberdeen
Scotland
Tel: +44(0)1224870070
Fax: +44 (0) 1224 870071
E-mail: sales@m-are.com
DanF
Workocean Limited