Tri Box Propulsion

[douglee25]

Has anyone every heard of this concept? I just found this cruising the internet the other day. I thought it was pretty interesting. I'm assuming it acts like a twin setup but with only one engine.

Doug

http://www.tribox.com/

 

[StressAweigh]

Never seem it. Not sure I would want it

 

[billandamy]

Wait...something is wrong with this rating system....how the hell could Doug be on a distinguished road? He owns a LARSON.
:grin:

 

[douglee25]

Wait...something is wrong with this rating system....how the hell could Doug be on a distinguished road? He owns a LARSON.
:grin:

I like this rating system... now all 'Larson comments' can get the kibosh! :thumbsup::smt043

Doug

 

[billandamy]

I like this rating system... now all 'Larson comments' can get the kibosh! :thumbsup::smt043

Doug

:lol: Very true Doug...you are well protected now lest the gods of point extraction smite they who sin against you.

 

[douglee25]

Too funny!

Doug

 

[tobnpr]

Too many moving parts for me (gears).
Stringers on a true twin screw likely aren't going to allow for a single engine installation w/out extensive modifications.
I call BS on "Twin Screw Maneuverability". Both screws are going to turn at the same rpm whether forward or reverse gear. That presents a BIG problem in handling IMO- I'd rather run a single screw than that setup. I bet the same boat/engine in a single screw setup would run faster/more efficiently than the twin screws- loss of efficiency and drag from another set of underwater gear. This is just ridiculous...

 

[duck]

Too many moving parts for me (gears).
Stringers on a true twin screw likely aren't going to allow for a single engine installation w/out extensive modifications.
I call BS on "Twin Screw Maneuverability". Both screws are going to turn at the same rpm whether forward or reverse gear. That presents a BIG problem in handling IMO- I'd rather run a single screw than that setup. I bet the same boat/engine in a single screw setup would run faster/more efficiently than the twin screws- loss of efficiency and drag from another set of underwater gear. This is just ridiculous...

I agree about too many moving parts, more moving parts more chances of failure :smt100

Tho i don't see why both screws have to turn in the same direction, a reverse on one of the screws would give counter rotation :huh:

 

[Kameroo]

I call BS on "Twin Screw Maneuverability". Both screws are going to turn at the same rpm whether forward or reverse gear. That presents a BIG problem in handling IMO

Agreed--would be difficult to use more power on one side vs. the other. With the prop pockets on many of the Sea Rays, that may be an issue.

I wonder why they didn't bother making the engine room look new when they installed the new engine? $$?

 

[tobnpr]

I said they'd turn at the same rpm- not necessarily the same direction. To effectively maneuver a twin-screw you need separate throttles for each engine. Independent throttles for each engine (fwd/rev) is what allows most twin-screw boats to spin in their own length.
Can't be done with this boat. Someone please tell me this isn't a joke...

 

[duck]

I said they'd turn at the same rpm- not necessarily the same direction. To effectively maneuver a twin-screw you need separate throttles for each engine. Independent throttles for each engine (fwd/rev) is what allows most twin-screw boats to spin in their own length.
Can't be done with this boat. Someone please tell me this isn't a joke...

Oh i am sorry, my mistake i thought you meant rotation.

On paper it seems one of those ideas that we all wish we had, you know like the wheel etc but in reality the system is floored on so many levels. Also if the shoddy website and poor pictures is anything to go by, i have a feeling these people wont be around long enough to sort out any warranty issues that will almost certainly arise :wow:

 

[fc3]

It makes sense if the boat is small and light enough that twin gas power is sufficient because then a single diesel will probably offer enough torque. Diesels are more efficient than gas engines. They make better use of the fuel they burn and the fuel has more heat than gas.

This idea improves on diesels in two ways. Firstly a single engine weighs less than two. Some of that weight loss is offset by some additional mechanical components, but not significantly. Secondly, engines have significant friction losses from the large number of moving internal components. The drag of the extra transmission is much less than the losses in a second engine. So net gain again.

There's a number of different ways to achieve this solution. Another fellow hauled out the engines from his 43ish foot Cruisers Yachts and installed a diesel electric propulsion system. One big diesels turning generator that powered two electric motors. This provided greater efficiency and control. The downside is that diesel electric is expensive up-front. He formed a company to promote the idea, but I think they are out of business, now.

Diesel electric work well in large vessels where the hotel loads outstrip the propulsion loads. Since they're generating a huge amount of electric power anyway, why not just generate a bit more to turn the props? Works really well with pod drives like the Azipod system since the pod further increases efficiency and the electric motor fits neatly into the pod.

Figure in a couple more years, once hybrid cars pay for more electric drive system engineering, diesel electric might come down enough in price to be competitive for pleasure boats. If they can get the price of a generator, two electric motors, and the electronic controls down to the price of a single diesel, it's a go. That mechanical system is significantly disadvantaged as tobnpr correctly identified. Diesel electric, on the other hand, does not have that problem. It's actually more flexible since it can turn the props over a wider range of RPMs than diesels. No more trolling valves, for example.

Best regards,
Frank C

 

[Newbie]

One of the biggest benefits of diesel/electric is that there would also be no lag. Electric motors generate its max torque throughout its RPM range if I remember correctly unlike an internal combustion engine where it gets it at a certain RPM and falls off either above or below it. My bet is that you will never hear about this tri box propulsion beyond this. SB