I’m still looking for varities of ships and boats to make into model kits. The dredger seemed interesting so I started with a basic hull, a shape I’ve now used many times and then added the dredger structure. The rotation was simply and the winch I’ve used before seemed to work but getting the bucket and the bucket arm to stay in place proved more difficult.

Above all I want the kit to be easy to assemble for a six year old and so any mechanism has to be as simple as possible. The kit also needs to fit onto four A5 sheets of 3mm plywood. Play value is also essential, my young testers check out this and other aspects of the design, especially it’s durability!
After some false starts I have used a living hinge and a cog arrangement on the bucket arm to rotate the bucket. The arm itself is also rotated with a similar cog winch but is held by a gravity pawl, giving just enough resistance.
This model will soon be available from Miller Toys and Models for just £18, 42 parts of press-out 3mm plywood, pva glue and string included.