Baz - Hi
For what it's worth - I came by the OPS 60 by chance - when I found the Astec site and the free drawings I just felt that this would be a good combination based on what I wanted to do
thirty years and more ago.
It would appear that this size of boat is very popular in the States and the class -1/8 scale hydros - recognises a max capacity of a '67'
Martin (Mayhems 'Mr Fid') has the same scale Circus Circus in which he has an OPS90. That's still as yet really untested as he has had radio problems but previously he put a CMB 90 in a same scale 'Winston Eagle'. That did not apparently last long before going airborne and doing a fair bit of damage. In my limited (very) experience I would say that this scale would be well overpowered with a motor of this size for good
average boating. It seems to me that going for max power has to be balanced with the ability of the craft to stay on the water - well at least most of the time.
If it's built reasonably light any good 60 should be more than sufficient for a good speed - you pays yer money etc.
Do you have any specific type in mind? ie side or rear exhaust, conventional or tuned pipe etc. Rear exhaust is probably better as there is not a lot of sideways room but with the right manifold it could be done with a side mounting. Bear in mind the fuel tank problem ie not much room for anything large.
I have without doubt made a few technical errors during building - if you would like any input please ask or send a PM Glad to help any way I can.
It's really great that you feel inspired to do like wise. My Huntsman is near finished so I will be able to get back onto the AvL fairly soon.
Hope this helps if not just shout.
Now... How about a bit more on that Slo-Mo-Shun
Regards - Ramon