British Motor Boat (BMB) outboard engines

[Adinsdale]

Hi there, in our spare parts room at work we have come across 2 outboard engines which we acquired a few years back. We believe they are both manufactured by British motor boat company in 1930-1940. Can anyone give me any more information on these please? Is there an owners club, accessible parts? Even if they're worth anything.

One of them is sort of an inboard which mounts through the hull of the boat, it's missing it's flywheel and some electrics.

The other is an outboard with a tiller and we actually had it running at one point in our tank but it over heated very quickly so we stopped it.

Any information would be much appreciated thank you.

[Charles uk]

The "first engine" looks like an early Mariner inboard (172 or 165 cc) & should be fitted with a 3 : 1 ratio lower unit, but yours looks like a 2 : 1 box from a later Middy (can you check the ratio, 2 or 3 revs of the flywheel to 1 of the prop).

The "second engine" has the wrong tiller arm & throttle assembly & is a Britannia, both look pre war but fetch very low prices, way lower than a similar age Seagull.

Most collectors buy 2 to ensure they all the parts to restore 1.

Prone to cracked cylinders, & ignition problems from a very unusual coil, what else could you expect from 75 year old components.

[Adinsdale]

The "first engine" looks like an early Mariner inboard (172 or 165 cc) & should be fitted with a 3 : 1 ratio lower unit, but yours looks like a 2 : 1 box from a later Middy (can you check the ratio, 2 or 3 revs of the flywheel to 1 of the prop).

The "second engine" has the wrong tiller arm & throttle assembly & is a Britannia, both look pre war but fetch very low prices, way lower than a similar age Seagull.

Most collectors buy 2 to ensure they all the parts to restore 1.

Prone to cracked cylinders, & ignition problems from a very unusual coil, what else could you expect from 75 year old components.

Thank you very much for the information, I'll have a look at work tomorrow what gearbox it has, is there anything we can do with them as far as collectors go? Is there anyone we can get hold of that would like the engines.

[Charles uk]

Where are they located, as they're not realy something you'd drive to Inverness from London to grab.

But there are a few on here who might be interested.

[Oyster 49]

Charles is right, they are both mid to late 1930s or even into the 40s. I thought the "Mariner" was the inboard with a reduction gearbox?

Any way there were 3 models, an outboard, which you have there, an inboard with a reduction gearbox to drive a propshaft in a boat, plus the middy. The middy was fitted to air dropped lifeboats, and also the canoes used by the commandos in World War Two. I rebuilt one of these (outboard model) a couple of years ago, and yes the tiller bracket is incorrect.

I have two of the previous "light twin" model for rebuild, again as Charles has mentioned you often need two engines to make one good one.

In terms of desirability, low to medium, value, nominal as spares or repair. Perhaps £50 each? They are not really in demand to collectors. Shame really as they have some good features such as 360 degree swivel and a inlet rotary valve.

As you have noticed the cooling system is complete rubbish, it relies on the prop forcing water up the inlet, and they don't seem to pump any water unless fitted to a boat moving forward, and it is impossible to tell if any cooling water is circulating. The cylinders seem to suffer a lot of corrosion too. The villiers magneto are similar to 1930s seagulls but a twin output coil to fire both pots at the same time. No relacement coils to be had, unless a seagull 1030 coil can be used to fire both plugs from a single output.

Somebody might be interested as a restoration project perhaps.

Where are you located?

[Charles uk]

Pre 1940 a vacuum prop cooling system would be normal, a la super single.

Wasn't a swan necked exhaust a Mariner sail drive fitment?

[Oyster 49]

See below, a 1946 advert showing the new swordfish, and the previous mariner model, with a fixed drive off take. Designed as an inboard installation, unlike the mid which was through hull.

https://www.flickr.com/photos/32134632@ ... otostream/

[Adinsdale]

Hi there, thanks everyone for the information- I'm amazed that theres not more of a collectors following for these engines as they seem very interesting motors. I work for a company located in Devon, I would have to speak to my boss to see what we will do with the engines, he asked me to do some research into them to see if they're worth keeping or not.

The advert you have sent a link for looks about right, I may have to have a go at getting one of them running again before Christmas. I'll keep you posted.

Thanks again

[Charles uk]

I've just had an email from a serious outboard collector who I belive has the complete set of these motors, this is the man I would ask for info on BMB's, it looks like I wasn't that right!

"Hi Charles.

Just read your posts regarding the BMB engines and I don't think some of your comments are quite correct – put it down to having one of your senior moments!


The 'first' engine is a 'through the hull' Middy and looks to be correct. Date wise, from about 1934 to possibly the mid 40s – but got no evidence when they changed the exhaust box from a swan neck to flange mounts at either end. I'm fairly sure the air-bourne lifeboat had a pair of these engines and was able to use handed exhausts.

The cockleshell canoe also had the later exhaust box, but the mounting flange was aluminium whereas this one is bronze.


There was another version of the Middy which had a steerable lower unit and was used in the Rytecraft Meteor and Scootaboats.


The 'second' engine is the Britannia outboard (you can just see Britannia on the side of the tank). Unfortunately I can't see enough of the bottom end to say for certain what this is. Most Britannia's with the square tank have an exhaust box with cooling fins, but as can be seen, this one is smooth just like the Middy. There is a version that used this exhaust which had a fish-tail bolted to where the exhaust flange mount is, and so it had an air exhaust instead of the usual underwater exhaust and so would date around the mid 40s. But unless I can see this fishtail and what gearbox it has then I'm uncertain – it could well be someone has put a Middy or Mariner engine on a Britannia leg!


Hope this clarifies things."

[Oyster 49]

This is the Britannia outboard I restored a couple of years ago, I sold it on to another enthusiast off this forum. On this one the water comes up the leg, into the pots and out of the pots into the outer exhaust, before going back down the leg. The exhaust from each cylinder goes into the inner silencer and exits from the side of the silver exhaust box. So the exhaust is actually water cooled. It would be OK if pumped, but this one relies on the prop forcing water up the leg from an inlet "scoop"

Also a very heavy engine. Interesting project at the time.

I have 2of the earlier light twin models circa early 1930s waiting to be looked at. It's a shame there is not more interest in Britannias, just as interesting to own as a early seagull I think.

[Charles uk]

Do your light twins have the push-me pull-you tiller arms Adrian?

[AusAnzani]

May not be very popular/collectable in the UK, but I would not hesitate to pick them up if they were in Australia.

Would you consider shipping?

Regards,

[Oyster 49]

Charles, yes both of the light twins have a sliding tiller arrangement that slides through for reversing. Also the tillers rotate to operate the throttle linkage. One has a villiers magneto, similar to the ones on the engines photographed here. The other is an early type, is it miller ignition? I dont' know.

I'll post some pictures in a day or two.

[wizo5]

Hello all,

Ive just inherited an old BMB engine, I believe its the Britannia Middy from the 1930s?

My grandfather used to race it on a home made hydroplane boat. Unfortunately, its been sat in a barn for close to 50 years.

Im hoping to restore the boat and engine, so any advice/parts/information would be hugely appreciated.

Many thanks in advance

Chris

[Oyster 49]

Hi, always good to see these engines turning up. Thats a Britannia but not a Middy. Do you have any more pictures so we can tell you a bit more about it?