Most Efficient Boat Propulsion

[tom kane]

You don`t need to use high spec materials for a fun experimental drive, high strength steel for propeller shaft even in salt water and other cheaper materials and you can hot dip galvanize some parts. A quick wash with fresh water when washing your boat.
Use composite water lube brgs in the torque tube ( only two needed) not any rubber types.I used Novasteen and they never did wear out enough to have to be replaced in any of my drives.

A steerable Pivotal Drive for cats of any size should have no real problems to set up.
As the shaft water seals would be above the water line (in most installations) the old boggy of leaking glands is a thing of the past and the rotation of the propeller shaft lifts water to cool the seal and glands although I did use ( stuffing box water glands) with water cooled channels just to try and never had heating problems. I only had some problems with motors and never any problems with the drives.

 

[myark]

Hi Tom

Great pictures on youtube
https://www.youtube.com/watch?v=r0rLsle0AMs

 

[tom kane]

TV1 New Zealand made a documentary film about the Pivotal Drive and also about the Safe Remote Fuel System for power boats (google).
But unfortunately they "lost" the footage and I have never been able to get a copy.

I would like one of these for Christmas as I am sure outdoorplay would do too.

 

[tom kane]

Images show an experiment using an electric driven propeller (when needed) in place of, and working like a rudder, to turn the boat and maneuver at docking with a Pivotal Drive retractable shaft drive S/P.

The gear was fitted to a separate transom so the original boat was nor changed.
.

 

[Agrodyne labs]

Tom...just wanted to say our bathtub boat project was originally designed with a trimmable drive...Pivotal you would say..Mostly to adapt to changing conditions.

When we create that piece of the puzzle i'll let you know.

 

[tom kane]

Surprise me Agrodyne labs. I look forward in anticipation.

 

[Agrodyne labs]

You won't have to wait very long...almost there.

 

[Canveysteve]

Image shows a fixed tractor propulsion which gave good performance but would it not be great if it was steerable and jackable..not akward tilting like others.

What make n model is this if poss

 

[tom kane]

Hi Canveystyeve, That propulsion was called a "Viking" available in New Zealand some time ago but for unknown reasons (probably financial) did not continue in production.
I may have other info which I will post if I can find it.

I had a tractor drive in one of my early dingy boats and had a lot of fun with it in shallow water fishing and an outboard as main propulsion.
I always liked a spare motor so I did not have to row home if damaged a prop.

 

[Canveysteve]

Think i have 1 ! Been trying to fing out for past 3 years what it is
Did it have a cable to steere the lower prop section as mine does

 

[Canveysteve]

https://instagram.com/p/BJeyXSFjzw2/
If the link works what du think ??

 

[tom kane]

I have not seen that drive before and it is similar to the ones I posted except that it is not a tractor (pulls instead of pushing) drive but it is steered by swiveling the lower half of the drive with cables.

I would love to know more about it. Let me know what you find.

Perhaps if you search old Sea Spray magazines online there will be information
about that drive.

 

[Canveysteve]

Will do annd gbanks for your help !!! Has helped alot !

 

[tom kane]

Surely the most efficient propulsion system must be the one with the least metal in the water to steer and propel the boat efficiently and the one with the least number of driven parts to do that.

And preferably the drive needs to be easily retractable for launching and retrieving and safe from damage in shallows from rocks and sand bars and many other advantages that an experienced boat operator should easily be able to work out for then selves.

From oars and paddles to top sophisticated drives easy retraction and de-mounting is a must have.

 

[OCB]

Drive with least metal in the water.

Surely the most efficient propulsion system must be the one with the least metal in the water to steer and propel the boat efficiently and the one with the least number of driven parts to do that.

Surface drive must have least drag and moving parts. Maybe a link bar to keep the prop vertical will improve reverse. Below are drawings of my design.

OCB

Surface drive for most efficient.



Subsurface for reverse flow under hull.




Storage/Service