Infinitely Variable pitch surface drive

Nos4r2 · 20 September 2006, 09:10

Saw this on the Southampton Boat Show programme last night fitted to a rib.

They showed film of the rib pirouetting on the spot and being berthed sideways. Who makes it? looked like an Avon or a Humber but the film was taken from a pc and quite low res. I was rather impressed.

It's not another one of Turbodiesel's toys is it?

codprawn · 20 September 2006, 12:44

Not one of these was it?

http://www.q-spd.com/models.htm

They were at the 2004 show exhibited by Bruntons

http://www.bruntons-propellers.com/news/

John Kennett · 20 September 2006, 18:37

If it was the one that I'm thinking of it's not actually a surface drive, but it is fully variable.

The one I saw at the show is fitted as a pair of drive units, even on a single engine installation, and uses hydraulics to change the blade pitch controlled by some very clever electronics. As the pitch of each blade is controlled separately you can get some very cool manouevering!

They reckoned on going into production sometime next year, with prices comparable to an outdrive (although I have my doubts about that). Can't for the life of me remember the name of the company but I'll try to find out.

John

John Kennett · 20 September 2006, 20:34

Actually I was wrong, it is a surface drive . . .

It's the Yellowfin VSD www.yellowfin.com (thanks to a well known speedboat captain for the reminder!)

Definitely one to watch with interest

John

PS Videos of it in action here: http://www.yellowfin.com/corp_vsd_in_action.html

Nos4r2 · 20 September 2006, 21:56

That's the one. Cheers John.

Searider · 22 September 2006, 09:23

Had a look at this system about 18 months ago. Was top secret then. Looks very clever and should be very efficient as there are no components causing drag - no rudders even!

Petter · 22 September 2006, 12:53

The Rib is a Valiant ST-PT 650.
Petter

codprawn · 22 September 2006, 15:33

Does look like it has great potential - would love to see some pics of it. I bet they will take the development so far and then sell out to a bigger company.

John Kennett · 22 September 2006, 19:55

Quote:

Originally Posted by Petter

The Rib is a Valiant ST-PT 650.

Which RIB? The one in the videos is a Ribcraft.

John

John Kennett · 22 September 2006, 19:58

Quote:

Originally Posted by codprawn

Does look like it has great potential - would love to see some pics of it.

It's a very impressive piece of engineering. Rather a lot to go wrong if they don't get it right though (not to mention the 4 squillion lines of code that it needs to run it!).

I hope they do well though. I really want to have a go on one!

John

Poly · 22 September 2006, 22:21

Quote:

Originally Posted by codprawn

Does look like it has great potential - would love to see some pics of it. I bet they will take the development so far and then sell out to a bigger company.

there are some pics on this thread on YBW

http://www.ybw.com/forums/showflat.p...gonew/1#UNREAD

not sure if it is the perspective but it looks like a big beast.

Nos4r2 · 23 September 2006, 00:07

Quote:

Originally Posted by John Kennett

Which RIB? The one in the videos is a Ribcraft.

John

The one on the boatshow programme wasn't the one in vids on the site-it had orange toobs as far as I remember.

This is a fascinating piece of engineering. I'd be very interested to see a slowmo of what the blades do while moving.

codprawn · 23 September 2006, 01:34

Quote:

Originally Posted by Polwart

there are some pics on this thread on YBW

http://www.ybw.com/forums/showflat.p...gonew/1#UNREAD

not sure if it is the perspective but it looks like a big beast.

Thanks for finding that - fascinating but looks way too complicated to me. The hub also looks rather large. Don't think it will be very cheap to build.

John Kennett · 23 September 2006, 06:00

Quote:

Originally Posted by codprawn

Don't think it will be very cheap to build.

The marketing man I spoke to on their stand was adamant that it would retail for a price comparabe to a sterndrive. Time will tell!

John

BogMonster · 23 September 2006, 10:44

Interesting, sounds odd on the videos too, like a cross between a Harrier jumpjet and a blender

Could be expensive if you start chewing on rocks too

Nos4r2 · 23 September 2006, 14:38

Quote:

Originally Posted by John Kennett

The marketing man I spoke to on their stand was adamant that it would retail for a price comparabe to a sterndrive. Time will tell!

John

That suggests to me that either:-

Sterndrives are made at an indecent profit,

They lied to the marketing man-or he's a liar.

Or they aren't charging enough for it.

It'd be nice if it was the top one.

Alex Brown · 23 September 2006, 17:49

This thing seems to give similar movement results to the Voith Schneider Propellor (variable pitch in any direction instantly) system, but in a different way. I wonder if they'd scale it up for the likes of tugboats with a high bollard pull as opposed to speed as the main output?

I could never see a VSP on a speedboat somehow, since there isn't one that spins fast enough (and they're not small), but for water efficiency, it's meant to be pretty good.

-Alex

John Kennett · 23 September 2006, 18:29

Quote:

Originally Posted by Nos4r2

That suggests to me that either:-

Sterndrives are made at an indecent profit,

They lied to the marketing man-or he's a liar.

Or they aren't charging enough for it.

It'd be nice if it was the top one.

His argument was that there are actually fewer moving parts than in a sterndrive, no gearbox etc, which will keep the cost down.

I would guess that they are more likely to make substantial long-term profits if they can price it to sell in large volumes. If it really can compete pricewise in the sterndrive market, and it works reliably, then it could really challenge the status quo.

John

John

John Kennett · 23 September 2006, 18:32

Quote:

Originally Posted by Alex Brown

I wonder if they'd scale it up for the likes of tugboats with a high bollard pull as opposed to speed as the main output?

There are apparently several sizes either in production or planned, ranging from something like 60hp to 1000hp.

The combination of manoueverability and efficiency should make it a winner in a very wide range of applications. Assuming the cost and reliability turn out to be OK of course . . .

John

Nos4r2 · 24 September 2006, 07:13

Quote:

Originally Posted by John Kennett

His argument was that there are actually fewer moving parts than in a sterndrive, no gearbox etc, which will keep the cost down.

That's interesting. That suggests to me (if he knows what he's talking about) that inside the bellhousing is just a couple of gears or a UJ and everything else that goes on is inside the hub.
I think it's probably arguable as to the number of moving parts though looking at the number of blades and their movement-but saying that they'll all be the same part that can be mass produced.

Quote:

Originally Posted by John Kennett

I would guess that they are more likely to make substantial long-term profits if they can price it to sell in large volumes. If it really can compete pricewise in the sterndrive market, and it works reliably, then it could really challenge the status quo.

John

John

It'd be nice if it did. The only market I can't see it impacting on is fishing-those blades would scare the crap out of anything close by.