Old girl on plane; 1970 53’ Hatteras motoryacht

LOLOLOLOLO

Can we keep the politics off this forum please?

Looks great ! Very nice and worth the mechanical effort.
Put all those antennas and flags down and you’ll pick up one more knot!

make that more of an Aerodynamic Hatt!

You and Oscarvan have to have a side by side performance race !

I ran a 1979 58' Yachtfish (same hull as pascals with a factory 5' cockpit added) and it had detuned 8v71 TI's with 90 injectors instead of the 110's......it only cruised at 13.5 knots at 1950, but at WOT it did get up and run 21 knots.......it was unstabilized......and sadly the boat rode and ran amazingly better at 21 knots as far as stability went. I always wondered how they'd run if someone put 600HP diesels in them so they'd cruise at 21+ knots, but over the years nobody has that I know of.......

That would remind me of the races I had as a kid. Me in my $10 1960 Ford with blown mufflers and bald tires against my friend in his $100 1961 Rambler. Sounded great with the roar and screeching tires and everyone jumped out of the way as our two hoopties putted up the road getting all the way up to 20 mph in 1/4 mile.

I think it looks very nice at that speed. Great restoration better than it was new. While I like faster, I find that the ability to cruise at 15 to 20 knots is a huge step up from only being able to run at 8 to 12 knots. I think the improvement you've made in your boat is great.

I thought you had used the 550 hp Cummins ?

During survey WOT at 2150 rpm we did 19.2 That was with 1/2 water , 1/2 fuel and empty holding tanks. We've since put "some stuff" on and generally run with full water and 1/2-3/4 fuel...... So I would lose that race. Maybe someday I'll put some big ass motors in it..... Not this week. Next week's not looking good either.

You need to take some pitch out of the props. 2150 rpms WOT is far too low.

Maybe it was in fact 2350. Props are as specked by Hatteras

In 1970??? Boats get heavier as they age, engines make less HP, bottom gets many layers of paint, etc. etc. Not uncommon to have to cut the pitch on the props as a boat ages.

1978. Engines rebuilt 900 hours ago. Bottom is not overloaded. But I will take your recommendations into consideration.

I'm of the Pascal and Capt J school also to always be able to reach maximum RPM. I like that for many reasons including speed and performance, but also to be able to objectively evaluate the performance of the engines and know if everything is well or not. I hear your argument, Mapism, but don't agree with it. I don't think you're doing the engines a favor at 9 knots. I think the biggest favor you can do is to always have engines properly tuned and properly propped.