Interesting thread all. Some well priced boats in amongst them as well.
Not that I am the most mechanical minded person in the world, but I am running a 200hp volvo diesel in my 7m cat. My cruising speed is pretty well right on 20knots and around the 3000 rev mark - I could ring its neck a bit more and get 22-23 knots out of it but its an older motor (1999) and having been sitting around for a few years, trying to look after it a bit.
Certainly I would love another 5 knots on the speed but having now been on a few trips across the bay in sloppy 1m seas, 20knots is plenty. The boat handles basically the same in those conditions as when it is a millpond.
I havent exactly worked out fuel figures but I am estimating around 30-35 l/h at cruising speed. Trolling for 8 hours doesnt even move the fuel gauge so like you smithy, would love a fuel flow gauge.
I too thought 200hp would be a bit underpowered to push such a heavy boat. Having been in an outboard powered cat, that certainly are completely different boats. The diesel just seems to punch through anything but the big difference is the duo prop. Getting on the plane is nothing and the torque is unreal. Spot82 has nearly thrown me out of the back of the boat a few times changing spots and I have nearly put myself through the windscreen putting it in reverse while docking it.
As I said, would love a bit more speed but I like the way the boat handles. For the money that I forked out for it, I wouldnt have got a new 5m boat let alone anything bigger.
This engine will hopefully get me through 3-4 years and will decide if a repower is the best option. Would love to fit in twin diesels but a 315 is more likely.....
Any yeah - leave the shark cat owners alone!!!