Model Boat Mayhem - Forum

Mess Deck: General Section => Tugs and Towing => Topic started by: Flundle (Speedline Models) on March 07, 2016, 08:07:29 PM

Title: bow thruster
Post by: Flundle (Speedline Models) on March 07, 2016, 08:07:29 PM
Whilst at Ellesmere last weekend I was chatting to one of the guys who was doing the tug towing on the water. He was looking at the jet drive I have done for my new lifeboat and was telling me that there was no really good, powerfull side thrusters available for tugs.
 
I use a Raboesch bow thruster at present for our Severn and Tamar lifeboats and they are very expensive and not very powerfull.
I have decided to make my own to replace these.
What are you tug guys looking for?
Title: Re: bow thruster
Post by: adamD98 on March 07, 2016, 10:46:50 PM
Well observed, they are rather expensive for not a lot of productiveness and something which is prone to leakage far to regularly.

 A lot of folk simply use a tube of sorts with an angled and shortened prop shaft, which is effective but it makes some boats skip around, which is not only unrealistic, but again is none productive. So, for me personally, and everyone will have a different opinion of course, something with actual props would be nice, which when combined with the right type of motor would provide just the right amount of thrust for the size of boat it is in. Oh, and relatively cost effective - of course  %) {-)
Title: Re: bow thruster
Post by: Klunk on March 08, 2016, 04:59:51 AM
And easy maintenance ie be able to to disassemble without awkward place screws ot bolts. Proper sealing gaskets etc and not too noisy!
Title: Re: bow thruster
Post by: Brian60 on March 08, 2016, 07:41:35 AM
I'm not too sure how your jet drive actually works however, from a simple to construct basis a two way pump that can direct a jet of water out of both ends of a 'across hull' tube would work. If the ends of the water jet can be disguised as coming from the centre of a propeller that would do most people. The prblem here would be having a pump with enough thrust to move a displacement hull like a tug.

Of course you can go completely over the top and build one with a 90degree gear train and working screw in a tube. Again the problem would be the gear train although small enough gears can be had I have some for a couple of azimuthing thrusters I am going to design and build. The propeller is going to have to be around 20 to 25mm in diameter anything smaller again would be ineffective.
Title: Re: bow thruster
Post by: Flundle (Speedline Models) on March 08, 2016, 09:35:35 AM
Many thanks for the swift responses. I was thinking about a right angle drive unit (with the small brass gears), driving the 28mm diameter three bladed impeller I use in the jet drive. In a tube which tapers down towards the impeller (from both ends). With a stator either sider the impeller, the swirl will be converted into thrust. That drive section would be almost 50 mm long
Does that sound sensible.
I will make a prototype of any new idea for someone to test if you like?
Title: Re: bow thruster
Post by: radiojoe on March 08, 2016, 09:37:56 AM
just a word for the Raboesch bow thruster ok agreed they are expensive, but I have one fitted in my 1:48 Hunt Class and although I've only done a couple of tests it appears to have ample power even at half speed it moves the bow of the 49" hull with ease IMO any more powerful and it would not look realistic. :o
Title: Re: bow thruster
Post by: Flundle (Speedline Models) on March 08, 2016, 10:16:44 AM
I think your right, they have enough power for the big lifeboats but for the tugs where they are used frequently and at full power, they don't provide the whooph! need (appartently). The pinion keeps coming off the Raboesch ones if used in this way.
Title: Re: bow thruster
Post by: TomHugill on March 08, 2016, 12:01:23 PM
Ron Perrott has made a proper now thruster with 90 degree bevel gear. It's used in Mike Higotts (sp?). It turns the typhoon which is a heavy 1700mm sub on a dime so has ample power. Might be worth contacting Ron?
Title: Re: bow thruster
Post by: Flundle (Speedline Models) on March 08, 2016, 12:34:31 PM
Many thanks for that. Do you have Rons contact details please?

Title: Re: bow thruster
Post by: Fred Ellis on March 08, 2016, 04:32:37 PM
 Try   http://www.rcsubs.co.uk/
Title: Re: bow thruster
Post by: Flundle (Speedline Models) on March 08, 2016, 06:07:23 PM
Many thanks. I have just emailed him.
Title: Re: bow thruster
Post by: cos918 on March 08, 2016, 07:21:47 PM
Hi
My ferry has 2 bow thruster . the small robbie ones . they work fine  . Raboesch may be expensive . To make a thruster is a hell of a lot of work. Have a look at this German shop. Makes Raboesch look cheep .


john
Title: Re: bow thruster
Post by: Norseman on March 08, 2016, 08:12:20 PM
What shop John?
Title: Re: bow thruster
Post by: cos918 on March 08, 2016, 09:15:16 PM
What shop John?




Sorry forgot to add the link


john


http://www.bauer-modelle.de/modules/wsShop/index.php?location_id=151&cat_id=83488
Title: Re: bow thruster
Post by: derekwarner on March 09, 2016, 02:39:42 AM
Isn't the version as detailed as below @ 318 EURO?......or about 8 times more expensive than the Raboesch :o ................... Derek
Title: Re: bow thruster
Post by: Brian60 on March 09, 2016, 08:23:40 AM
That is what I am going to make for my next build Derek. I need 4 and I reckon I can turn them out for less than 50 for them all (without the propellers). The gear trains only come to 16, the rest is machine work and casting.
Title: Re: bow thruster
Post by: derekwarner on March 09, 2016, 10:59:23 AM
Evening Brian........if my memory serves me correctly :o, you did mention [some months ago?] using 4 x the same thrusters in a build.....not for a tug, but for an off shore positional constant requirement?........... Derek
Title: Re: bow thruster
Post by: march show on March 09, 2016, 11:28:43 PM
I was the guy you were talking to and for the tug towing you cant just have a realistic looking thruster in the same way you cant scale wind or wave we do give them some stick but only when the scale is tipped way against us a trip to balne moor would enlighten a lot of people and even get them hooked well worth a trip
Steve
Title: Re: bow thruster
Post by: Flundle (Speedline Models) on March 10, 2016, 01:49:29 PM
I emailed Ron and he is sending some pictures to help.

Title: Re: bow thruster
Post by: J.beazley on March 10, 2016, 07:09:05 PM
That is what I am going to make for my next build Derek. I need 4 and I reckon I can turn them out for less than 50 for them all (without the propellers). The gear trains only come to 16, the rest is machine work and casting.
Brian if you can churn out the gear train for such little funds I'm sure plenty of folk will want a few, I know I will  :-))  props from Propshop would look superb on them too.


Jay
Title: Re: bow thruster
Post by: Brian60 on March 11, 2016, 07:12:17 AM
Brian if you can churn out the gear train for such little funds I'm sure plenty of folk will want a few, I know I will  :-))  props from Propshop would look superb on them too.


Jay

Check out slot car gears. They come in bevelled as well as straight cut versions in steel, brass and delrin. Take your pick, they are matched so all the hard work is done for you, it just leaves you to make the housing. ok2