Mystery Volvo?

[Corpus Skipper]

In my latest issue of Sport Fishing was a tantalizing ad for Tiara Yachts with "Volvo Penta's revolutionary inboard propulsion system. Coming soon" Anybody got the skinny on this? Volvo's web site didn't show anything.

[D'ARTOIS]

Yes, we do. Although it is still not introduced, Volvo will within a very short time introduce a new (revolutionary?) propulsion system.
The actual novelty is the propulsion, a dual pull prop, mounted in a pod under the hull, of special design, will or could replace the old sterndrive as well as Z-drive.
As I am out of the office now, I have not the full details at hand but if you are interested let me know and I will give you all particulars.
Brien Gilroy D'Artois, International Marine Technologies

[Corpus Skipper]

I think everyone here is VERY interested!

[woodboat]

Apparantly cruisers is using it as well.
http://www.powerandmotoryacht.com/news/1204fyi/

[D'ARTOIS]

OK guys, I' ll sneak into our 'secret files' cabinet and get the details. My colleague, who handles the engine department in our company, brought a press
map that he had received at a press conference and had showed it to me afterwards.
The engine + propulsionsystem will be officially introduced in a few weeks time, actually I am not allowed to 'leak information' - however we are not discussing mondial strategic topics and the only special thing at the drive system is the propulsion unit that works like pulling the boat instead of pushing the boat.
I.e. the propellor works in the other direction - that's the general line - as I remember. I did not expect this to be so hot. Wait a few days till I am back in the office and I will reveil the secret. The press-folder is quite complete.

[Tad]

See this :
Volvo drives

They are puller Dual-prop steerable struts, which are large enough to provide some directional stability, and they incorporate the exhausts.

Volvo claims an efficiency increase of 35% over convention drives. I would assume they mean straight shafts with single props and struts and rudders. The good news is that the up charge over conventional will be considerable, (but worth it for the increased efficiency
) and it will all go to Volvo.

The inexperienced will buy the increased efficiency, at the cost of ridiculous vulnerability. And when you hit something it will mess up two expensive (cast bronze) drives, shafts, four propellers, endless seals, and all the money goes to Volvo.

Tad

[brian eiland]

About three years ago I had mentioned my interest in such a configuration to the Volvo rep at the Ft Lauderdale show. He said I should come visit them in Norfork. I never did take the time to follow up on that invitation. I suspect they have been working on this for some considerable time.

I had previously suggested this idea for both single and/or duel props, but utilizing a kevlar belt drive component rather than 90 degree shafts:
http://www.runningtideyachts.com/power/
PYI is now using a Morris chain drive component in lieu of the kevlar belts:
http://www.pyiinc.com/?section=drive_leg&sn=1

I still believe the kevlar belt idea merits research, particularly in this forward facing config., and as simplier, less expensive possibility.

[D'ARTOIS]

Look, I get the feeling that on the other side of the swimming pool there is little sympathy for Volvo engines, and to be strictly frank, my experiences with Volvo and their services aren't that great either.
I started with boats from scratch. The first I bought was a sec Zodiac with a rotten Mercury (Mercury is on the same list as Volvo) then I bought a brandnew Zodiac Mk III with a Yamaha, then my little son complained about the rough rides of the Zodiac ( we were using it on the North Sea, not the most comfortable piece of water) and then I bought an Italian Cranchi with an inboard Volvo engine.
After maybe 10 engine hours something broke in the gears, in any case the damage was considerable. Volvo refused to give any warranty. They said me to go to the Italian manufacturer (1000 miles away). All this happened 27 years ago. I never bought a Volvo again and when I became involved in building yachts, I never proposed Volvo, neither any other Swedish product. But that's another story.
I have meanwhile co-owned a shipyard producing around 45 motorcruisers a year, mostly for inland use, some, a few, for open sea. For those boats my favorite's were Cat's, Deutz, MAN, NO Detroit, marinized v8's etc., NO Italian's either.
I have driven also a few Offshore's with V12 Lambo's and/or Isotta Fraschini's. The most beautiful engine I saw was the WWII RRMerlin 12 cyl mounted in a home-made racer. That boat did about a 100 nm/hr with the roar of a Spitfire in a dive....

[brian eiland]

Couple of older references on the belt subject, on this forum:

http://www.boatdesign.net/forums/sho...81&postcount=4

http://www.boatdesign.net/forums/sho...2&postcount=11

[brian eiland]

Originally Posted by D'ARTOIS

Look, I get the feeling that on the other side of the swimming pool there is little sympathy for Volvo engines, and to be strictly frank, my experiences with Volvo and their services aren't that great either
....

Speaking of engines, I would ask if their are many persons having experience with Isuzu diesel engines in marine service. I just had occassion to purchase a used Isuzu diesel engined box van. The engine runs like a top. And everyone I talk to praises the durability of these units. And now that I'm aware of these vehicles I see them EVERYwhere. And none of them seems to be running poorly or spuing nasty exhaust.

[D'ARTOIS]

To Brian Eiland,

Japanese engines have a considerable marketshare here in Holland, Isuzu has a name as being a reliable and low consumtion clean engine.
Kind Regards
Brien Gilroy D'Artois

[TrendSetter]

I am getting excited here to see this new technolgy, and more so to see if it takes or not, the duo-prop was a big hit for them, so i guess if merc follows in the foot steps and does it better then them, they got a hit. I just hope they have a wharehouse full of lower units? since it is sacrafical when they finally hit something at speed like a dead head... but i agree the with one of my mechinics in the yard always says when ever we have to work on Volvo's.. The Sweds should just stick to porn!!

[yipster]

35% efficience increase!? (over conventional shaft single prop?) and what a trustvectoring and more claims...

so where would that place it on a chart? i remember you Brian mentioning the beltdrives, i too wrote volvo ay several occasions for a pleasure boat size shaft driven duoprop without any succes, gues if and when they bring it it will be pointing forward?
cant repower BIII's but hey, this is progres...

[tom kane]

A tractor drive prop for the average bloke,40 years old though.

[brian eiland]

from Scuttlebutteurope:

Ted Jones commented:
I suspect Gordon Hargraves has never been shipmates with
a forward facing propeller. I had one on my IOR Half-Tonner in the 1970s
with which I never had a weed/lobster pot warp problem in several years of
racing and cruising the U.S. east coast between Cape Cod and around
Florida to Tampa Bay and The Bahamas. The prop was designed by Dieter
Empacher (Hood Yacht Systems) for rating advantage. It was a two-blade,
fixed pitch prop which worked fine. Beside the rating advantage, the yacht
would back up under complete control (don't try that at home). If it had
fouled with kelp, or whatever, it would have been more difficult to clear
as it was further under the boat, but it never did.. I'm sure this was
nothing like the new Volvo Penta system, but the latter shouldn't be
criticized simply because it points the wrong way.