Volvo Penta IPS

[gonzo]

Tom Kane: usually in inboards 15 degrees is all you can run a shaft. Does the double prop setup allow a bigger angle and is still efficient?

[Danielsan]

The sterndrive Duoprop installations as Volvo and Mercruiser have them, have an improvement in efficiency? would it be less when it runs in a duoprop straight shaft setup?

Gonzo?
What would be an ideal shaft angle? less than 15 deg as with a casale gearbox? or even less maybe combined in a slight tunnel in the hull?

greetings?


PS should I put this in an other thread?

[FAST FRED]

"A Volvo Penta diesel has more than 1000 hrs of life."

Depends , today most engine designers figure service life bases on a certain amount of fuel will go thru the engine , not hours.

An example is the Detroit Diesels , where a 6-71 in a 1200rpm gen set will run 20,000 -30,000 hours ,
BUT the same engine with a blower in a sports fish will usually only run 1000 hours and be shot.

Both will have consumed the about same amount of fuel in their lives.

For anyone ever contemplating a Volvo they should go to the Volvo web site and examine the "conditions" placed on the HP use and hours.

The BIG Volvos are competative as marine propulsion power units EG have a cont duty 24/7 /365 rating.

The outboard or I/O competative Volvos have loads of restrictions , or the service life is SEVERLY reduced , and the unit will be operating OUT of its designed limits.

Fine on a ski boat , MUCH UNGOOD for an ocean vessel.

FAST FRED

[Dave Guilford]

Saw an IPS system under a Regal at the Miami Boat Show. Looked like a pretty solid design. After all, they're the same guys that invented outdrives a million years ago.

[tom kane]

Originally Posted by gonzo

Tom Kane: usually in inboards 15 degrees is all you can run a shaft. Does the double prop setup allow a bigger angle and is still efficient?

You can run a shaft angle from well above horizontal to well below 20 degrees..if you wanted to.Efficiency from horizontal to 15 degrees of shaft angle would be difficult to measure,if there was any..on a particular set up.Many shaft boats run a motor at 10 degrees and 10 degrees spread over twin universals.There are many options,and none need to be complicated.

[tom kane]

Originally Posted by Danielsan

The sterndrive Duoprop installations as Volvo and Mercruiser have them, have an improvement in efficiency? would it be less when it runs in a duoprop straight shaft setup?

Gonzo?
What would be an ideal shaft angle? less than 15 deg as with a casale gearbox? or even less maybe combined in a slight tunnel in the hull?

greetings?


PS should I put this in an other thread?

Duo props on a single shaft running on their hubs in S/P mode should beat all.Shaft angle alone,can be misleading there are other considerations.

[Danielsan]

Tom, do you mean dual counter rotating prop on one surface drive drive?

couldn't be that complicated, could be almost same constrution as with straight shaft as I see it.

[tom kane]

Danielson.Just take a look at some of the top surface drives,yes they are complicated and so are many inovations on modern autos but they still achieve better fuel and performance.A simple drive like they run hydroplanes on obviously as yet has no equal for speed for general use.Twin contrarotating props on a single shaft may be acceptable some time in the future.Would you risk financing such a drive.There must be easier ways to make a buck.Drives come and go and are revived again.Image shows a very small tunnel in a hull.

[tom kane]

Originally Posted by Dave Guilford

Saw an IPS system under a Regal at the Miami Boat Show. Looked like a pretty solid design. After all, they're the same guys that invented outdrives a million years ago.

Was it not Jim Wynne who patented the basics of the modern inboard/outboard tilting inovation in 1960.I have the patent No if you want it.

[FAST FRED]

""yes they are complicated and so are many inovations on modern autos but they still achieve better fuel and performance.""

WHAT??? Better??? Your kiddin

I had a second hand 1958 Renault Dauphine that regularly got 50 mpg at 65 mph.

Even had a real heater , unlike the VW of the era.

Where are the "improvements" in milage for all the complexity of the new Hybrids?

Most get LESS than 50mpg on the highway , and need engineers that haven't been born yet to keep them operating.

Throwaways at $25,000 a pop?

The old Dauphine could be kept running with lawnmower tools.

Progress is great , if it ever comes!

FAST FRED

[tom kane]

Do not despair FAST FRED..I am inclined to agree with you..but still working on your thinking.

[jmariner]

Unfortunately, this system would be immpossible for the pacific north west region. The props and drive are simply too vulnerable. I spend silly amounts as it is, maintaining the drives after (even small) debris HITS! The Arneson drive system shoud be further explored for pleasure boat/trawler applications.........and not so ridiculously expensive.

[tom kane]

How would a drive like in post #70 suit those conditions..but with a Kort nozzle or propeller shroud or in a tunnel..single screw.It is possible to have a rugged low cost drive that can be protected from damage,and still be efficient.

[gonzo]

jmariner: have you priced an Arneson? They are not designed for trawlers or slow boats. What do you mean by small debris damaging your drives? Drives, of all major brands, take a lot of abuse.

[cyclops]

Small debri in the Pacific Northwest is a 6" X 30' log.