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National DM2 electrics


billh

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Electric starter motor fitted to this engine and an ex-Jaguar alternator mounted on the floor on the starboard side driven by a pulley in front of the flywheel.All works well enough but I want to tidy up the alternator by fixing it by bracketry direct to the engine. Am I right in thinking that the original DM2 powered GU boats had a dynamo fitted? If so has anyone got a picture of the installation so I can pinch some ideas? Thanks

Bill

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No. You're not. electric lights were by battery charged at the depots and swapped out. there was no dynamo on a National and most alternators are driven by belts on the flywheel, which gives a cracking ratio.

Thank you for that. I am now free to design something that doesn't have to look original 1930's. The electrical demands of this old boat are very modest , so there is no need of an expensive "Leece-Neville" or similar, also a flywheel rim drive has proved unnecessary ( but has worked well for many years on a Kelvin in another boat.)

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No. You're not. electric lights were by battery charged at the depots and swapped out. there was no dynamo on a National and most alternators are driven by belts on the flywheel, which gives a cracking ratio.

I've only just picked this up - I'm afraid you're incorrect, they were fitted from new, batteries being swapped between motor and boat as required. For pictorial proof, look at The National Bulletin No. 158 August 1936, page 6!

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I've only just picked this up - I'm afraid you're incorrect, they were fitted from new, batteries being swapped between motor and boat as required. For pictorial proof, look at The National Bulletin No. 158 August 1936, page 6!

Thank you,can you provide a link to the picture or copy it to here?

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I am grateful to Margaret Clark, who had the foresight to rescue this material some 50 years ago, for letting me reproduce some of it here. To quote from the text "A vee belt is fixed to the flywheel and used for driving a small electric generator for lighting purposes" and elsewhere "A small dynamo attached to the engine charges the accumulators and the butty boat accumulator is changed over to the motor to be charged up every week"nO5FXnU.jpg

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Superb! Thank you for posting that picture. I am surprised at the position of the dynamo, I had the idea that it would be low down on the right of the engine somewhere near the oil pressure gauge. I will have a look at fitting as original. Somewhere , I have a Lucas C45 dynamo( ex Austin A95) and an RB106 regulator, though the latter, in my experience, don't work for long without re-adjustment. Probably stick with the rather less super-annuated ACR20. Thanks again to archie57 and Margaret Clark.

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What's the bit of pipe sticking up at the front?

 

Richard

Cooling water out, though it does seem to head off in an odd direction. The one here also has a by-pass valve to re-circulate back to the pump to keep the engine hot- similar to a lister JP.

Bill

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Cooling water out, though it does seem to head off in an odd direction. The one here also has a by-pass valve to re-circulate back to the pump to keep the engine hot- similar to a lister JP.

Bill

 

Straight up is a very unusual direction. I wonder why?

 

Richard

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Standard fitment on GU boats, either to keep a bit of back pressure on the plunger pumps or to keep the pipe out of the way rather than heading straight across the engine room or to help deter any syphoning effect...or a combination of all three perhaps?

 

Where did it run then? Up to the roof then - where?

 

Richard

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Up to the roof, over the side 'walkway' down the cabin side and out through the hull.

 

Fulbourne's runs up to the roof, forwards and then down the inside of the corner between the engine 'ole bulkhead and side, discharging just below gunwale level just behind the bulkhead. This was installed along with the National c 2000 by Tim Wood. I can't be certain, but imagine the hole in the hull side is the original.

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Would that be the Margaret Clark who lived on Sorceress at Higher Poynton, in the Mrs Burgess days?

Yes it is, the "Sorceress" , so named as a condition of sale from BW, has reverted to it's original name of "Mercury"

 

Where's the picture of Mr Coles and his daughter?

 

Richard

 

I'm afraid you'll have to wait to see Mr Coles!

 

Superb! Thank you for posting that picture. I am surprised at the position of the dynamo, I had the idea that it would be low down on the right of the engine somewhere near the oil pressure gauge. I will have a look at fitting as original. Somewhere , I have a Lucas C45 dynamo( ex Austin A95) and an RB106 regulator, though the latter, in my experience, don't work for long without re-adjustment. Probably stick with the rather less super-annuated ACR20. Thanks again to archie57 and Margaret Clark.

 

I'll pass on your thanks to Margaret!

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  • 2 years later...

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