Bow thruster

[RonP-UK]

As far as I know there has never been a full size sub that utilized a bow thruster, but then again I know of
no full size sub that sailed in a canal or swimming pool or local duck pond.
For many of us here in the UK getting a large sub around a small pool is quite a problem.
With that in mind I put a bow thruster in the Typhoon I built for a friend but you can't buy a suitable device
over the counter so, here is a simple to make idea for a unit to do the job. The only challenging bit is getting the gears in mesh and then locking everything up. To achive this one bevel gear is locked onto the drive shaft and the other freewheels, this keeps the drive gear in mesh and takes care of any side thrust.
Again one prop is locked onto the shaft and the other screwed in until mesh is achieved and locked into position with a grubscrew. I hope this appeals to some of you and you might have a go but as before
my designs are subject to copyright and I would not like to think that commerce would take advantage
of designs I give freely to fellow submariners.

[Kazzer]

I've suffered from pitiful maneuverability in my pool with my 1:32 S Class (British WWII), and have been thinking of adding a bow thruster to it. I was given three or four of these devices by the Raboesh CO. who market them in numerous sizes. I have a feeling I gave my samples to The Wizard, because I can't find them. Not that I have time at present to tinker with submarines, I'm still painting, remodeling and trying to find stuff after my move to our new house last year.

Here is a photo of some of the units. I could carry them in stock if there is a call for them.

Not to steal your thunder Ron, but they are available commercially. It's still a neat gizmo for the competition. I'd be interested to see how you wired it up.
Is it somehow in tandem with the rudder servo?

[Slats]

I have several of these units in various targets. Keep in mind that these units work best when the model is either stationary or at a slow crawl.

A big sub in a confined space will always tend to have turning problems.

Working on getting the sub ballasted right can also improve things., i.e. trim excess weight down and get the COG perhaps a little further back. David's Cabal report on the Alfa part 7 is a must plain english read for ballasting / balancing / and trimming.

Whilst scale purists would hate doing so, for a sub with ongoing turning problems an enlargered lower rudder can be of use. Have done this several years ago when I was clueless to ballasting, -done via a clear piece of arcylic bolted on to a scale rudder.


J

[Slats]

Ron, that is a very nice piece of engineering there, do you use a water proof seal for the shaft, or do you run the shaft in the free flood area back to a shaft seal on the WTC to a motor within?
J

[RonP-UK]

Thanks for the compliment John,
the whole unit is in the free flood and the shaft connects back to the pressure hull or seperate motor box. I wire them up with a couple of micro switches and link to rudder servo
so that the trim switch turns it on.

[Subculture]

Good stuff Ron.

A lot of submersibles use bow thrusters, so they are used in full size boats, just not the big military ones, although I believe the Typhoon does have some auxiliary thrusters for manoeuvring.

I have a little Deep Quest submarine on the go which is going to get twin vertical thrusters. I have two four blade kort type props (square tipped) which are about 18mm diameter from the prop shop and after a lengthy search found a place that sells tiny bevel gears under 5mm diameter. These are moulded from acetal. Still thinking how to hold them on. Maybe friction will be sufficient if I make a press fit perhaps with a dab of Loctite as a belt and braces measure. With a shaft size of 1mm pinning or grub screw would be an interesting proposition.

On a side note, a lot of German modellers use Whale or Reich centrifugal pumps for thrusters. One on each side as they're not bi-directional. As you can get these for about a tenner off ebay, twenty nicker for a bow thruster isn't too shabby.