Tug Motors

[Malcolm FraryParticipant @malcolmfrary95515]

At least with car heater/fan/window motors, you look at the fuse feeding them. An ESC with a higher rating (apart from the infamous 320A units) is going to be fine. Agreed about the guesswork regarding actual pwer, though.

[Paul TParticipant @pault84577]

Hi Malcolm

Thanks for joining in I wish that some more people would pitch in with their opinions and experiences

Your suggestion is a good rule of thumb guide but the problem with a large tug weighing in excess of 220 kilos is the initial current spike taken by the motor as it starts to move that mass, yes the ESC is protected by a fuse but in this scenario the tug is going nowhere without a bigger ESC or playing russian roulette with the existing one

Paul

Edited By Paul T on 23/04/2017 14:18:06

[Ray Wood 3Participant @raywood3]

Hi Paul

Sounds like your in the realms of the set up for fullsized electric outboards or mobility scooters/golf trollies are a good source of motors & speed controllers which match, there is a company called 4QD who sell model locomotive speed controllers maybe worth a look.

Or I've a Sinclair C5 motor in the shed which is big old 12volt lump ! which your welcome too for the postage ?

Regards Ray

[Paul TParticipant @pault84577]

Hi Ray

You are right about these being potential sources of equipment but they are a bit haphazard and difficult to use when looking for a specific size or power output.

My problem is not finding the odd motor for a one off project as I have a shed full of these things, my problem is that from the designers perspective there is a lack of fully specified 'off the shelf' motors that are suitable for large model tugs.

Paul

[Kev.WParticipant @kev-w]

I'm left wondering exactly what it is that you are building & whether it will in fact float

In 1 post you talk about 3-4 foot tugs, then you say it will weigh in at around 220 kilos.

9 sacks of potatoes weigh 225 kilos, I just can't imagine a 4ft model tug floating if it weighed that much.

You will need to purchase a forklift truck to get it in & out of the water.

Edited By Kip Woods on 24/04/2017 13:20:48

[Ray Wood 3Participant @raywood3]

Hi Paul

That would be a conundrum, I guess there is not much demand these days, from a transportation of large models angle ?

Regards Ray

[Charles OatesParticipant @charlesoates31738]

Am I alone in finding this thread a bit confusing?

Anyway, to try and help a bit, we were loaned a model tug for our exhibition last year that weighed about 200 kilos. It was vast, around 9 feet long and totally useless without industrial lifting gear. Only good as a talking point for press and visitors.

On a more practical front, my mate Gary's Thames tug is about 4 feet long, weighs 20 to 25 kilos and sails superbly.

He uses a 3 inch prop, with an MFA 919 motor and gearbox at 2.5 to 1 ratio. Current draw is around 4 to 5 amps normal running. Usually he only puts 6 volts in the model, but occasionally uses 12 volts for a bit of fun, or heavy towing. It can go like the clappers on 12 volts, way over scale speed.

I know these figures are correct because I helped him with a repair last month and checked things out myself.

Lastly, a query regarding the t12 and t24 motors, you mentioned that published info was inadequate, what was the response from the company when you asked? Did they refuse or not have the details?

[Paul TParticipant @pault84577]

Gentlemen I am afraid that you might have missed the point slightly.

The point of my ramblings is the lack of suitable motors.

To explain : If I were designing a 2m tug I would have to work out the 'all up weight' which could be as much as 220 kilos, for this mass of model I might need 500watts of power to move it……Where can I go to find an off the shelf motor suitable for a model boat that meets my needs?

A design for a 3 to 4ft tug would have the same problem as no model boat supplier can provide large motors with full technical details.

BTW. When designing such a large model I draw them with split hulls and removeable motor, battery and ballast packs so that they can be assembled at the lake side or even in the water.

Paul

[Dave MilbournParticipant @davemilbourn48782]

Paul

"You cannot be serious!"

220 kilos is (almost) the combined weight of you and I! It is not a realistic weight for anything which could reasonably be considered to be a model boat. As such, there would be only a tiny number of people interested in building such a beast – and therefore very few customers for suitable motors and speed controllers. By "few" I mean you could probably count them all without having to take your socks off at 10… I would have thought that 40-50lbs (18-22Kgs) would have been more of a realistic upper limit. I may be wrong but I doubt it's by a factor of ten.

I'm reminded of a bloke who rang me up after Balsacraft had put the 1/4 scale Stampe SV4B on the market and told me "What you want to design next is a 1/4 scale DH Dragon Rapide". I said that wasn't quite true, because what he really meant to say was "What I want you to design next is a 1/4 scale DH Dragon Rapide". We might have sold one.

A model boat weighing the best part of 1/4 tonne would be a novelty and certainly not something I would consider worth catering for commercially.

Dave M

[Charles OatesParticipant @charlesoates31738]

Hi Paul, I can't see how I've missed the point. You mentioned a 200kilo model, and I mentioned the total impracticality of the only one I've ever seen. You asked for details of installations and I gave details of a successful one. Incidentally, the specs for that motor / gearbox are on their web site. I'm still wondering about the specs for the t12 etc, so if you have them I would be very interested, if not, I'll find out for myself.

I can totally understand your frustration in collecting and collating data on motors, seldom are the figures we need quoted, but for most of us, asking a mate or the forum suffices.

[Kev.WParticipant @kev-w]

Posted by Paul T on 07/04/2017 19:00:46:

Dear All

But especially those who sail tugs in the 3 to 4ft range can you please help me by answering this simple question.

What motors do you use?

Can you tell me some or all of the following.

Manufacturer, Voltage, Watts, RPM and prop size

Ok, not quite 3ft, but 35 inches is as near as damnit ……………….

Fitted with 2 Mabuchi 555 motors on 12v 7amph sla batteries, drawing less than 5amp each & turning 60mm props in fixed korts.

Goes like a 'good un' pulls like a train & will do so for 2 hours.

Who needs expensive custom motors, when these at £9.00 each off the shelf at Comp. Shop are more than capable. (specs below, courtesy of Comp. Shop)

[Malcolm FraryParticipant @malcolmfrary95515]

A (brief) look for a contender turned this – http://products.damen.com/-/media/Products/Images/Clusters-groups/Tugs/ASD-Tugs/ASD-Tug-5114/Documents/Product_Sheet_Damen_ASD_Tug_5114_04_2016.pdf – up. Doing numbers, to be about 2 meters long, gives a scale of about 1:25. Deadweight of 720T gives just over 100 lb, the power of the real thing scales to about 500 watts, so a fairly knobbly brushless outrunner with a low KV number that would pull about 20A (or up that to 150% to give a sensible conversion to model conditions) and a gearbox.

A trolling motor or two would probably be the answer for a very large "model" like this. Might even do the azipod thing in one go.

[Paul TParticipant @pault84577]

Wow so much controversy about mass but it has generated a lot of great commentary. I am sorry to cause so much confusion but the 220 kilos is an accurate mass figure for the mythical 2m tug.

The answer is to consider the difference between a cabin cruiser and a tug.

Paul

[Malcolm FraryParticipant @malcolmfrary95515]

That's why looked for a real tug. Knowing the claimed power of the real thing allows a very reasonable guess at the power that the model's motor will need, After you have that, it becomes a question of gearing it to match the prop. Or not, depending on the motor. But doing a search for trolling motors showed some items in the right power range that didn't 'arf look like azipods.

[Dave MilbournParticipant @davemilbourn48782]

Paul

There's no question that your figure for a 2m tug is inaccurate. After all, 2m is longer than I am tall and I've managed to reach 135kg in this highly streamlined package… well, that's compared with a tug hull!

The point I was trying to make is that the demand for such a huge model would be so small as to make it commercially questionable to design, develop and produce a "straight-drive" brushed motor specifically for it. If any high-minded philanthropist wants to go ahead then fine – just don't expect them to fly off the shelf, and if they do then make sure your foot isn't immediately underneath. As Malcom says, I reckon a big knobbly brushless motor and/or a gearbox would seem to be be a better option.

Much the same goes for a suitable speed controller.

Dave M

[John W EParticipant @johnwe]

Hi there – large models are okay and finding power plants to fit them can and has been done – have a look at the link that I have posted about this guy's model/s. Where this all falls down is the physical size of the model and the weight – that is where it all falls foul if Dave remembers the first Mayhem when Marc took my Leeds Castle model down for me – he had a 'people carrier' to take it in – and my car I took the 3 batteries to power it (3 x 12 volt 14 amp batteries) and this gives you an indication of the actual weight of the model – it took two of us to lift it into the water. Although it has been sailed several times – it spent most of its life sitting on the shelf. This is due to the fact that its like an Army exercise to get it ready to go down to the water . There aren't many people who participate in model boating who are prepared to spend a lot of time at the lakeside preparing the model ready to sail it and this is only one of the downsides of any large model. Just my experience of it and my thoughts

**LINK**

John

 

 

Edited By bluebird on 25/04/2017 08:19:53

[Francis MacnaughtonParticipant @francismacnaughton39461]

My experience of powering a 4.5m 300lb 1/32nd Type 42 destroyer is described in more detail elsewhere on this forum but it did involve a fair bit of experimenting with gear ratios and motor windings to get a reasonably efficient and controllable set up. As John has said, the market doesn't really support the large model so a degree of testing and tuning seems inevitable

[Paul TParticipant @pault84577]

Dear All

Thank you all for getting involved in this discussion and for graciously accepting the data that I presented, it has been fun but I am guilty of being slightly caviler with the figures of the mythical tug, yes a model tug weighing 220kg would be a very large beast or even ‘f-ing huge’ as a good friend described it in a recent email.

The caviler aspect of the 220kg is that the calculations included the expected mass of the tug and its towed load, the tug itself would weigh in at approx 75>80kilo and I used a simple rough multiple of 3 to get the total mass for the motor to move.

I apologise for moving the goalpoasts around a little bit but it was done for a good reason as I wanted to generate discussion.

Charles

Thank you for your input but regarding your question about the company that supplies the T12 & T24 I think it would be unfair to report on anything other than what is already in the public domain. It is up to the company concerned to decide whether or not to publish details about their products.

Dave M

I was being serious about the subject even if my figures were slightly ‘tongue in cheek’. I now have a further problem of nightmares regarding your 135kg slimline package.

Kip

Thank you for bringing the information about the Mabuchi 555 motors as they certainly fit the bill for tug motors.

Malcolm

Your proposal of using a fairly knobbly brushless outrunner has given me something to think about although I have to admit to a huge gap in my understanding of these types of motor.

By the way what is ‘trolling motor’

John

I would have really enjoyed seeing the Leeds Castle sail and I can fully appreciate the logistical problems of moving such a large model around never mind the stress and strain of actually getting it into the water.

Francis

Thank you for relating your problems when sorting out your Type 42 and I agree with both you and John that there is lack of information and equipment for larger models although as Dave quite rightly says there would be very little commercial return for any company investing in such equipment.

Thanks to everyone

Paul

[Malcolm FraryParticipant @malcolmfrary95515]

Trolling motor – a very quick goggle turned up loads – https://www.amazon.co.uk/Boat-Trolling-Motors/b?ie=UTF8&node=469898031

They are a self contained electric out-ish board intended for helping a small rowing boat along with a fisherman on board. About the same size boat as being discussed, oddly. Obviously some hacksaw work involved with the structure of the thing, but we are modelers, are we not? I came across the term on a US website, where they seem a popular choice for oversized models.

[Gareth JonesParticipant @garethjones79649]

I never realised these things existed or were so, relatively, cheap. You learn something new every day.  Excellent information Malcolm.  It's not that I am ever likely to use one but you never know, if I ever take up Paul's Thor challenge.

Gareth

Edited By Gareth Jones on 26/04/2017 10:26:32

[Paul TParticipant @pault84577]

Hello Malcolm

Thanks for the answer they seem like a good source of heavy duty motors.

Hello Gareth

As you might have guessed I have moved on from Thor and looking at something slightly larger.

[CookieParticipant @cookie15923]

Hi Paul , we have one of these motors on our club rowing boat ,it is about the size of a shoe box which contains the motor and bevel drive to the shaft .it simply clamps to the transom and propels the boat with 2 blokes in it at a fair rate of knots .I don't know the exact price but I remember people commenting how cheap it was.

Best regards Dave

[ashley needhamParticipant @ashleyneedham69188]

Those trolling devices look really cheap considering what it would cost for you to make one. Not only that but they are designed for years of life so have to be rugged.

​Ashley

[Malcolm FraryParticipant @malcolmfrary95515]

Probably rugged – the rule that you get what you pay for might well apply, so a bit of care and reading user feed back would be in order. There is an increasing awareness that the lowest cost might not offer the same quality as something a bit further up the market, but trolling motors do seem to be a big market so unit costs and competition might result in low prices and good reliability.

[CookieParticipant @cookie15923]

I will be starting my next model shortly which will be a large 4ft tug,so I need to be looking at the motor required to do the job. I have spoken to a lot of people who rave about the smith motors fitted to most British cars to cool the radiator , I know it sounds odd but surely they all can't be wrong , I remember them in the 80,s they have a triangular mounting flange . these motors are still available brand new but I can't find any specs for them . the prop is a 80mm 4 blade type so I am looking for about 4000 rpm ,if anyone as used these motors and as the specs that would be much appreciated.

Regards Dave

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