Best inboard for 40-45 ft motoryacht...

what do you recon?

I've been told that the Volvo Penta IPS 600 would be best......do you agree?

 

biglogigalo,

What speed are you desiring from this boat, is it displacement , semi or planing?

Let me assume it is the average semi displacement hull shape, 40 to 45 foot would require about 270 hp to run at about 18 knots.

The Cummins QSB series of electronic injected engines are really good, never any smoke out the exhaust (of course) and super quiet. No diesel noises anymore, they almost sound like petrol motors compared to the old style engines.

 

somewhere between 30-35 knots, it would be same hull as say the wally power 47 scaled down to 43 foot...

which takes up the least room?

 

That sort of speed will take some serious design work and hp (and a big , deep pocket to run)....are you up there?

Don't fall into the trap that you can simply scale down a design to achieve the same sort of results.....there are no free lunches in this game my friend.

 

ok well think of it as a 43 foot hull of very similar design to the wally power 47...

all the big uk 4 run twin approx 300hp engines....im thinking along those lines...

 

To get a 40' boat up to 30+ knots will take some HP, and of course tq, but that's a given w/ diesel. I just looked at last months Boating Magazine, where they did a test of a Monterey 400 Sport Yacht, and it had twin Volvo IPS 500 drives at 352hp /336 cid and where swinging T5 props thru 1.94:1 gears to make 35.6 knots w/ a 22,000 lb displacement. Hope this helps.

 

yeah it does thanks, the volvo penta ips seem to be the best, is this true? are there any close competitors?

 

Not with an inboard tractor drive- VP is the only company doing it. For a 40'+ boat you options are IPS or inboard shafted.

 

Read from page 42 at http://www.proboat-digital.com/proboat/20070405/

Enjoy,

Pericles

 

great, thanks!

 

Just thought I'd chime in with a 200 hour report on the Zeus system.

Boat is a Sabre 42 Express with 425HP QSB engines.

Displacement about 35,000#

35+ knots at 3000 RPM (rated RPM)
26+ knots at 2600 RPM

Fuel curve from new has improved somewhat.

Skyhook is good, but not as capable as first advertised.
Joystick control is very nice, however yaw reaction changes with load (as one would expect) and the inertial sensor does not compensate as much or as quickly as it could. This leads to yaw excursions when using the Skyhook when lightly loaded (30% fuel and water), the system can be "tuned" to have zero yaw at only one load. Fore and aft trim changes due the size of the saddle tanks are the culprit ... a Sabre issue, not a Zeus issue.

Compared to the 550HP option the fuel usage is indeed about 20% less for the same speeds with a noted exception. Between low speed economy (750+ nm range @ 8knots 1050 RPM) and high speed economy (335 nm @ 80% throttle & load 2550 RPM) there is a "why bother" area. 12 knots to 20 knots the range is lower than at 23-25 knots. The published information on the Standard 440 HP engines shows better range and economy in the 10-20 knot range.

I know this thread is old, but it is very hard to find feedback on either the IPS or Zeus systems.

Thought I'd share a 200 hour / one year report.