.... however, I'm putting a 540 motor in, and when I looked at these mounts in the boat I realised two things -
Firstly, (since I'm adding the length of a UJ connector) the motor extends too far forward to allow the battery box to be mounted where it should be.
Secondly, the sloping motor mount would make it extremely difficult if not impossible to remove and replace the motor if it became necessary later. Anyway, since I'm using a UJ I don't need a sloping mount.
Similarly, it's hard to get at the servo mount screws like this.
SO - I've decided to do my own thing with the mountings - the arrangement will be approximately like this, with everything aligned as centrally and as low as possible . The motor mount will be as near vertical as I can get it so that I can mount/remove the motor easily.