Hello,
when I was a young boy I sometime assisted the owner and driver of the Let's Go and Let's Go 2 boats.
The owners name was Ken Brakespear or similar and all I know about the boats themselves was that they used old Buick straight 8 petrol engines.
These boats competed with the Kookaburra boat(s) that ran from the middle of the Manly Pool walkway which of course was blown away in one very bad southerly storm.
The Let's Go boats ran from a floating wharf which was towed around from its mooring at Forty Baskets moorings and the boatshed at the bottom of Bolingbroke Parade.
I have been trying find these boats myself.
John