looking for a suitable diesel/petrol engine for an ‘unusual’ model boat

[Sam Longley 1Participant @samlongley1]

The instructions for the lister LT1 diesel engines fitted to concrete mixers used to show how to fit air cooling plus a Watermota feathering propeller for marine use. The LT1 was superceded by a much smaller diesel. I have one fitted to a generator. But forget the code it may simply be LT2, It is already more powerful.

The LT1 can be up rated from 1.5Hp to 7.5 HP by balancing the flywheel & fitting a throttle. There are a few other small adjustments. I had one done by Thurston Engineering at Ongar in Essex. So I expect that the later model can be treated the same.

It is very small & if you can track down a second hand Watermota prop & shaft with feathering box you will have a very lightweight unit. You can actually run the engine at constant revs & just feather the prop.

If you can track a prop I will flog you the diesel if you want. You often see them in tarmac rollers in the 5cwt range – Stoddert & Pitt type. I had one in my Greens roller, so they have a lot of power.

Edited By Sam Longley 1 on 23/01/2018 20:29:14

[Howard LewisParticipant @howardlewis46836]

As an aside, based on your stated intent of buying a lathe and milling machine to make the engine.

DO find a local model Engineering Club, and join. Unless it is a strange one, members will provide lots of advice and help, from obtaining machines (used or new), and help and advice on equipping and using them, as well as this forum. There's nothing to beat someone local who says, when you hit a problem, "Bring it over, we'll sort it out together"

Howard

[Russell EberhardtParticipant @russelleberhardt48058]

Posted by Howard Lewis on 23/01/2018 21:51:41:

As an aside, based on your stated intent of buying a lathe and milling machine to make the engine.

DO find a local model Engineering Club, and join.

That's difficult to do in Mark's (and my) part of the world. There is a national club, the CAV, which I joined some years ago but I was the only member in my department!

Russell

[Mark BruttonParticipant @markbrutton84977]

Good evening, everybody. I am once again overwhelmed by the generosity of your responses. Jason, let me start with you, and your obviously good suggestion that I should go for an SC4 lathe and SX2 or SX2.7mill, and build Bill. Yes, I am more than ever persuaded that I should build my engine, and the building of the boat will have to take a back seat while I get to grips with that. I have watched everything I can find about these machines, and have read a good thread on this forum about them. Especially charmed by the guy who has his in the spare bedroom. I am accustomed to woodworking machines that are greedy for in/out feed space. This is such a compact world by comparison. ARC looks like a good, niche supplier and it seems the forum has a special relationship with Ketan Swali. I will ring him/them tomorrow to check prices, especially the price of shipping to France, which might be cruel (if it's £65.00 inside the UK). I am glad to see that old friends Axminster are also suppliers, but they seem more expensive. Regarding Bill: it makes all the right noises, so why not? A pretty-looking thing too. I'm just a little concerned about its staying power, when it's out on the water and headed for Algeria. Assuming I do a good job making it, can I trust it to stay running? Maybe someone would care to comment on that. Regarding the boat: Jason, do tell me, where did you find the excellent 3D visualisation that you included with your post? I have found nothing so good myself.

Meanwhile, in other posts:

Russell, I thank you for tipping me to Optimachines, for a supplier based in France. But of course, I note that you say Arc in UK is competitive even with the shipping.

Howard, I hear you (join a local model engineering club). I would do that at once if I lived in UK. But here in the south of France … there just isn't one. I know without asking that I am right about that. Russell, I now see, confirms it. First thing I did when I had this crazy idea was, Google for model engineering exhibitions in France. Nope. Not one.

And to the many of you who have offered so many ingenious ideas about old engines that might be found and modified … well, it might happen by accident. Someone might say, here Mark, have this motor that my grandfather used to use for crushing grapes (that's actually an example from life). But thing is, I really don't know motors as an engineer knows motors, so I am ill equipped to go looking. It is just not my game. But I do know tools, or so I like to think. So learning a new tool suits me just fine, and is actually a thrill to do. D'you see?

I will of course keep the forum thoroughly informed.

Cheers

Mark

[JasonBModerator @jasonb]

Google is your friend, plenty more like that here

I suppose most would put a model on a boating pond or lake rather than risk it in open water so maybe an electric backup would be wise.

[Mark BruttonParticipant @markbrutton84977]

Thank you, Jason. Not sure why I didn't fall on those pics myself. Yes, the boat will certainly have an electric auxiliary motor. For top points, driving the main prop through some kind of gearbox that also provides forward/neutral/reverse for the i/c propulsion, and maybe allows the electric motor to serve as starter motor, bendix pinion and all. All to be resolved once hull and Bill are built. Who knows what the final drive gearing will be.

Cheers

Mark

[Russell EberhardtParticipant @russelleberhardt48058]

Mark,

Before you choose an engine you need to consider what power you need to propel a boat of that size. I'm guessing that it would have a displacement of about 200 lb (speed for a given power will be proportional to the cube root of the weight) . At 6 ft long it will have a displacement speed of about 3.7 kt. Below that speed its speed will be more or less proportional to the motor power and, assuming that the propeller is well matched, 1 hp should give you about 3 kt.

The Bill engine was rated at 3 hp so the 1/3 scale model is likely give at most 0.3 hp and thus a speed of under 1 kt. That might be enough if you are only going to sail it on a pond but not if you wish to sail it in the sea.

Russell

[Mark BruttonParticipant @markbrutton84977]

Hmmm. There's a circle that needs to be squared here. I'd be happy if the boat were smaller, just has to be big enough for the motor, and the motor has to be big enough for the boat, and round and round we go. By your figures, I need a motor that's maybe ten times the power of little Bill. Or the boat has to be a lot, lot smaller, and maybe too small to fit Bill. Do you see a way out? I'd be grateful for your thoughts.

Mark

[JasonBModerator @jasonb]

I suppose it all comes down to what you want out of the model. Do you want a scale hull with a scale size engine that will look correct but may lack some performance. Or do you want to make a scale hull with more performance and don't mind having an out of scale engine plonked in it?

Funny enough all thees model loco's that are running around track have more or less scale size boilers and cylinder and all seem to perform well enough same with traction engines, 1/3rd scale ones will have scales parts but will run well enough

Edited By JasonB on 29/01/2018 17:48:46

[Brian CorrieParticipant @briancorrie54124]

I wouldn't worry too much about power. I have a Seagull Featherweight of 1968 vintage which will propel me, kit for a weekend and the 8' Avon inflatable dinghy, total at least 150kg at 3 knots into a moderate headwind. Inflatables have very poor drag characteristics too.

The original output claims for Seagulls were very overstated, and the Featherweight is actually about 0.8 or maybe 1hp. They push a lot of boat though because they have a relatively large prop, low revs and don't cavitate so much as fast outboards. Mine will in fact push my 22' 1-odd tonne sailing boat quite well, just not very fast.

[Mark BruttonParticipant @markbrutton84977]

I expect the engine to be out of scale, physically. Really as big as can possibly be fitted under the deck. We need no room for the fish catch here. Though I have wondered, did anyone ever build a radio-controlled model that caught real fish? Probably …

[SamsarandaParticipant @samsaranda]

Mark, I have reservations about the Jerry Howell engine “Bill” being able to power anything but a very small boat. I am currently building one and although it looks a fair size, the cylinder bore is only 1 inch, that isn’t going to generate much power. My choice to power a boat of any size would probably be the V Twin that Jerry Howell designed, should also give a pleasant exhaust note. I must say that since starting my “Bill” I am impressed with Jerry’s design. Good luck with your project.

Dave W

[Neil WyattModerator @neilwyatt]

The speed of a displacement hull is determined by its length.

To get a 'scale' wake a scale model needs to travel at a speed given by:

Scale speed = prototype speed/(square root of scale)

So for a 28-knot destroyer modelled in 1:48 scale a scale wake will be achieved at 28/7 = 4 knots.

You can use the calculation for any size of displacement hull.

It does not tell you the power required but relatively modest power will get a displacement hull up to neraly its cruising speed and huge power is needed to go faster.

With planing hulls all bets are off

Neil

[Russell EberhardtParticipant @russelleberhardt48058]

Mark, a small correction to my post. I should have said, "speed for a given power will be inversely proportional to the cube root of the weight"

I think the problem you have with the Bill is because of scaling. At 1/3 scale the swept volume will be 1/27th of the volume of the original so the energy per stroke will be 1/27th. I assumed that you could run it three times as fast. Of course running a small engine fast to get the power you need will not give the put-put sound.

A possible solution to get the power in a small engine would be to increase the number of cylinders. E. Westbury's Seal Major is said to be capable of powering a six foot boat and is a possible compromise but more complicated. Castings and drawings are available fom Hemmingway.

Of course once you have the engine it is important to match the propeller diameter and pitch to the power and speed but that's another calculation to do.

Russell

[Paul LousickParticipant @paullousick59116]

Mark,

Would one of these Westbury Wallaby engines be suitable for your boat. Available as a kit which you would have to machine.

Paul

**LINK**

 http://www.hemingwaykits.com/acatalog/The_Wallaby___Edgar_T_Westbury.html

 

Edited By Paul Lousick on 28/02/2018 00:15:20

[Mark BruttonParticipant @markbrutton84977]

Thank you , Paul, the Westbury Wallaby might well be perfect for my purpose. I have just spoken to a nice man at Hemingway Kits and, yes, the power is about 1hp, which forum opinion suggests is what I need. For the benefit of everyone who has been so generous with their advice, let me tell you all where I have now got to. Yes, I remain committed to the idea of making the engine myself. Learning to do that comes before all else, and I am looking forward to learning. And magically, it seems I may now have found my first lathe. Very old, probably South Bend (I am waiting to hear), needs some work I am told, but doing/commissioning that work will help me to get to know it. And magically, though it actually belongs to a friend from England, it is already just down the road in France! And its owner who is absolutely the ayatollah of metalwork will be at my elbow to guide me. Sounds like destiny, doesn't it? I will of course pass details to the forum when I have them, and look forward to comments from all. "Hey, Mark, you lucky man, that's a classic!" I do hope so …

Til the next

Mark

[Russell EberhardtParticipant @russelleberhardt48058]

That's a nice looking engine Mark. 1 hp should give you somewhere between 3 and 4 knot maximum depending on the weight and assuming that the propeller is well matched.

For marine use you will need a pump to bring in sea water for cooling and a wet exhaust system. You will need to flush the engine out with fresh water after use to avoid corrosion of the alloy castings.

Congratulations on finding the South Bend, a popular lathe in the U.S. and many parts are still available from the original manufacturer.

Russell.

[Adrian GilesParticipant @adriangiles39248]

Another slow running four stroke engine to consider would be the Villiers/BSA "sloper" from an old Ransomes Marquis mower. Big flywheel, very easy running, go on for ever. Our fitters used to have competitions to see who could get theirs to run slowest, really nice exhaust note too!

Ad

[martin perman 1Participant @martinperman1]

May I suggest a 1.5hp single cylinder Lister D petrol engine, it is a long stroke engine, slow revving max 700 rpm and if you found a radiator cooled version you could remove the radiator and draw in with a pump the cooling water and pump it back out.

There are still plenty to be found for, depending on condition, £50 – £150

Martin P

[JasonBModerator @jasonb]

Can't help thinking a Lister D is going to be a bit big in a hull that is only going to be about 6ft long. Looking on the net it seems the engines that some of these use in full size are not much bigger than a lister, like this one for example

[martin perman 1Participant @martinperman1]

If the boats that small then he wont find a long stroke of small dimensions and I will most likely be a two stroke.

Martin P

[JasonBModerator @jasonb]

One of our newer members has just posted a video of his "bill" engine, you can hear why I suggested this as an engine that would meet the criteria of a "pop pop" engine.

[Mark BruttonParticipant @markbrutton84977]

Yes, the Bill does make the sound I seek. Lovely job by its maker. But I feel increasingly committed to the Wallaby, despite the huge challenges thaty it represents for me who knows nothing. "Increasingly committed" = I have ordered the plans from Hemingway Kits. Hemingway's Kirk Burwell has listened patiently, and for lathe he suggests that I should at least take a look at the stock held by Home and Workshop Machinery in Sidcup. Old-school advisors have worked hard to put me off new Chinese options, and buying off eBay is complicated for me, coming up from the south of France and just praying that something good shows up in the short time I would be in the UK. The widow who is eager to sell her late husband's entire workshop … H&WM say most that I might find on eBay will turn out to be incomplete, and by the time I have found and bought what's missing, I will have paid the price of something complete from them. Well they would say that, wouldn't they? But it does ring true for me in my long-distance circumstances. So is it to be one of their Myford Super 7s for probably £5000 by the time we're finished? Plus £250 to ship it south, and I won't even think about the infinity of additional tools that I will also surely have to buy. At least I'll take a look, with advisor at my elbow. It looks like a good place to start.

And if there's any widows reading this post … please do get in touch.

To be continued

Mark

[Mark BruttonParticipant @markbrutton84977]

I have found my lathe, and what a strange chain of events has led me there. Was it to be Myford classic or Chinese? I swerved this way and that, and had finally decided that I would buy Chinese, just for convenience. But does the Sieg have a vertical side? No it doesn't, and none is available to fit it. I was just calling to check that point, when I got the wrong ARC Machine Tools. Instead, I got a super guy who asked, would I like to buy his own ML10? With vertical slide. Yes! It is coming by truck next week. In the meantime, I continue to wallow in YouTube, and especially Steve Jordan's channel. I will follow Harold Hall's 'Lathework: A complete course' and butcher miscellaneous materials that I find in the flea market. Steve Jordan is an inspiration in this respect. See what he does with an old snooker ball …

Cheers

Mark

[Michael GilliganParticipant @michaelgilligan61133]

Posted by Mark Brutton on 06/05/2018 15:55:24:

I have found my lathe, and what a strange chain of events has led me there. [ … ] I got the wrong ARC Machine Tools. Instead, I got a super guy who asked, would I like to buy his own ML10? With vertical slide. Yes! …

.

Serendipity !!

MichaelG.

.

P.S. … I see he's also got a rather spectacular Rotary Table

http://arcmachinetools.co.uk/machine-tools/miscellaneous/rotary-table-1/

Edited By Michael Gilligan on 06/05/2018 19:46:39

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