Im pretty sure weismann has made 3 and 4 speeds for a couple of years. The zero defect skater had them about 6 years ago in open class.

You never have to worry about prop selection, they would also downshift the inside drive just before the turn. made the boat turn awesome.

Curtis

Yes, that's exactly what Lamborghini did with their trannies. They had a 5 speed out before this type of thing was outlawed by UIM. Prop selection was still important though. But this was also a safety factor. Now, with single speeds, there are actually more accidents in class 1 because guys are forced to stay in the right RPM range in order to have the right torque which sometimes obliges them to push too hard into turns, go too fast in rough water... hence the accidents. The reliability of this type of trannie was never really adequate. But once again, if a major corporation like ZF or Twin Disc got behind the idea, they could probably make it reliable. Proof is, ZF made their 2-speeds very reliable after having some problems initially so I think it's just a matter of time before they start thinking about 3, 4 speeds and so on...

I’m looking for a set of multi speed transmissions for an application. There is absolutely no way one can invest in only one propeller and merely shift gears to get what you want. I’m still scheduling in the same propeller pitch and range to get the boat where I want it, I just want the acceleration of the multi-speed gear boxes.

The issue is COST!! And with the ZF space! The ZF 2 speeds are long, some 16” longer than a single speed transmission. This makes them less than practical in most installations, especially with a 6 cylinder diesel engine. The Seatek and Yanmar engines are long and make a tight installation in a boat even with a single speed.

Pat’s transmission used a compressed gas (O2 or CO2) to shift the drums and the Lamborghini uses an electric solenoid. I like the gas idea as it would be hard to fail unless your bottle ran out. Life span on these things is another issue I’ve been told.

The sand drag guys are using a Makita Drill motor to shift the drums, but I have to believe that sand is far slipperier than water.

Rik,
Did you go to outback????
What hp, what torque, speeds?
Call me sometime.

We use air for several reasons. An air compresser system with an accumilator instead of a bottle works well. We used dive bottles in racing for weight. It is easier to replace air than oil when you are in the middle of the ocean and you have a leak.
We had a 6 speed we made in 98 for Mr. Serralles. VT shelved it.
Solinoid developement is slow but coming along with the advent of direct injection, camless motors ect..
Shifting a boat and shifting a car are not at all the same. In a car you have a clutch or a torque converter. Boats do not.
Un-syncronized shifting is the norm in cars. Semi auto in cars still use syncros and a hydrolic shifter in place of your arm (not to tricky) and clutch control (tricky).
Without the clutch in there (boats) shifting is tough but not that tough.
Durability is always a problem when you increase a part count. That is why I do not like blowers and turbos. NA with a gearbox instead.

pat W

Made it to Outback on Sunday night. Hour wait and everyone else got sick off the food.... (Don't eat the meat in FL)

The budget isn't there for the new ones. I hope to find some of your used ones for a reasonable deal and then get you to set the gears at the splits I want.

800 hp N/A @ 6,500 rpm fairly light displacement would finish off the project with the right touch if I could get a set of tranny’s at a deal.

SHIFTER:

Good to have you here again. Could you please tell us more on this topic of drives that can handle diesel power and more info on your drives.
This topic has been one of the best ones in a long time.

RIC and Super Termoli :

Thanks for all the information.

Yes, the automotive shifting is different but the analogy remains a good one I think. Once again, how fun would your sports car be if it only had second or third? You would enjoy the combined effect of pathetic acceleration and ridiculous top end.

Rik is right in pointing out that the main problem of that machinery is its length. Which illustrates my point that if you want to use new technologies and step away from mainstream stuff, the best thing to do is to re-think your powerboat. Most semi-custom and custom manufacturers will accept to move the bulkhead for you and make a longer engine compartment. It will cost and it will be a pain but it's worth the effort. You will not regret doing it and you'll certainly never go back. Sure, your cockpit will be a foot smaller but it's amazing how many girls you can fit on those extra-large sunpads.

It's a lesser problem to move a bulkhead and make things longer than it is to widen the boat and retool everything. This is why all those things, including motors have been developed in length. For example, a Seatek is an inline-6 even though a V8 configuration presents certain advantages such as a shorter and thus more rigid block. But a 10.3-liter V8 would not fit in width so it's a case of choosing a lesser problem to solve. Offshore powerboats being long and narrow, width is a scarcer commodity than length...

Rik,
It breaks my heart to hear about Outbacks.
Do you need to shift on the fly? Up and down?

Length of the transmission is not a problem. We did some new dropboxes recently that have the output 6 inches from the block face.
Everything is possible.

On our drives we are continuing the testing with several new boats this year. I like our products to speak for themselves, with time we will get all the facts out there.

As far as diesel sport boats. I feel that every boat has a perfect drive type. If the boat is kept in the water I would pick a simple drive because of corrosion. Rudders are great for high speed applications not so great for docking and low speed performance. There is no fits all drive out there. They all have baggage. For instance Jet drive is good as long as you keep the power on.

We are not parcial to any system, we go with what makes the most sense to what the application is.

pat W

Pat,

Do/could you make a transmission that could take a 1000 hp/1500 ft-lb input and split it to two drives with some sort of torque limiting devices that would prevent feeding more than, say 800 ft-lbs to any one drive? Of course, incorporating an overdrive into the gearbox would also help the torque situation.

Then, you could fit ONE really big V8 diesel into a skinny boat, but feed the power to two readliy-available drives.

A friend of mine has a custom 34 Phantom with 2 Yanmar 315/Bravo pkgs. Reliable, fuel efficient and an overall carefree package. Basically a Phantom F2 style pleasure boat that we can run from Sarasota to Key West in 4-4.5 hours on 110 gal of fuel. Top speed of 70, cruise all day at 50-60. Call Will Smith, visit www.phantomboats.com.
Domenick