SD parts

[Hugz]

I'm after an SD 10" raked 2 bladed prop stamped with 3157. Also a std length SD drive tube. And a steel tank preferably with bayonet cap included. Any leads please advise me. Thanks.

[Adrian Dale]

In answer to SD Parts:

To my limited knowledge (given there is no one yet that has full knowledge) the SD's were all long shaft no standard shafts were manufactured. I have two SD's one cut down the other original long shaft, reason for long shaft only lies in assumption that when the ministry of (MOD) defence would have written specifications for the engine. They would have specified length prop properties and speed requirements. We will never know as no detailed specifications have survived, except that the MOD had detailed ministry of defence had specs for all of its bespoke equipment, from tanks to field guns. This process continues today in Australia. The Mod issued a detailed specification for their new submarine upon which manufacturers could bid for the build, competing countries included France, Germany and Japan. One requirement was that new submarines must be on the condition that new subs would be built in Australia. France eventually won the tender process intinteresestingly for the Brits the UK was not asked to bid. Britain having lost its design and ship building industry including construction expertise gained and perfected over decades was not considered as a suitable candidate. As for my self working in the offshore oil industry in the 1980's as a marine project engineer, the first task on being allocated a new project was to revise the standard company specification to suit the conditions of the new project. One difficult problem was the fire pumps. Several OTC papers had been written on the subject of passive corrosion in stainless steels, it was known that even the highest grades of stainless would suffer from this condition when exposed to continial submersion in salt water . On the platforms fire pumps needed to be instantly available starting up with maximum torque and high on the power curve, a stainless steel pumps hung in a steel cason could not be relied on to do this, so with the help of a brilliant mechanical engineer Bill Giger, we demanded in our specifications that the piump manufacturers use Titanium impellers and shafting adding to the cost by more than 100% above their standard pump designs. As the criteria for acceptance was technical acceptance followed by lowest price, even the major manufacturers fell in line, prices were eye waveringly expensive, but for the security of reliability, the pumps were procured. I only mention this as a modern day example of a process that was almost certainly dictated by the MOD of wartime UK my appoligies for the numerous editorial mistakes but to day is the 2nd anniversary of my devastating stroke and I'm still on the very slow path to partial recovery.
Regards AJ, tip don't sandpaper your balls.

[Hugz]

Thanks Adrian,

Good to hear you are slowly recovering. I call the SD torque tube a std shaft as there is only one length as you quite rightly observed. 26". Any non standard ones would be cut down and be shorter. Though we do have an SD in Australia that has had the length extended by a few inches.

I often wondered who put out the specs for SD's. The Ministry of Defence name changed in 1964, prior to that it was called War Office though still known by its previous name as the War Department. The operating instructions were put out by the Ministry of Supply. I would imagine that the Royal Engineers would have an input as well. Probably a collaboration of them all.

Good info on fire pumps. Stainless steel is not the be all and end all then re corrosion. Safety before expense is reassuring.

[Horsley-Anarak]

I will dig this one out Hugo, I still have the power head and leg. Gearbox went to Bermuda, flywheel ignition. prop went to Jersey, fuel pipe has gone.

Fairly sure leg has "not" been cut down as it has the hole near the gearbox, will need a closer inspection, leg not chromed zincplated/galvanised I think from memory.

Seagull carb cowl, are we sure this can be ruled out as an original part, may have been fitted to later ones.

Transom bracket has one of those plastic thrust bit, who wanted one?

Gear shift

Seagull patent.

Could there have been shorter SDs, I wonder, or just post war improvement of surplus stock.

H-A

[Hugz]

I would be most appreciative of that Allan. Would you still have the other 4 componects of the leg, ie shaft, water pipe, exhaust and clutch rod? Save me from having to fabricate them.

Was that the tank that you cut and welded the bayonet filler so as to have it positioned centrally for your marston? I was impressed with that exercise.

CharlesP does have some documents that show the cowl was patented during the SD time but whether they produced it for the later SDs is unknown. A crated SD still in its original wrapping surfaced a year or two ago which appeared to have the shape of a cowl under the wrapping (Thanks Jacob). As this motor hasn't been verified as original it is not 100% conclusive but my personal view is that the cowl came out on later SDs.

The data coming in shows the so called short shaft lengths differ which would indicate they are not factory plus the parts list only have one length. I agree with your synopsis on this.

For record purposes can you recall if the box had the CIESS stamp?

Cheers, Hugo.

[Horsley-Anarak]

For record purposes can you recall if the box had the CIESS stamp? Cheers, Hugo.

Yes well stamped.

Will look for the bits that I have.

H-A

[Hugz]

That's the best stamp l've seen yet

[Horsley-Anarak]

This one is OK as well.

[seagull101]

Not bad Allan, only 206 earlier than mine. I must ask though, why break such a tidy motor?

I seam to remember that my SD has a very clear stamp as well, in fact ive not seen many that are worn away.

[Hugz]

The stamps must be hand made. Notice the arrows are a tad different or am l being finicky?

[seagull101]

They look the same too me! Notice the tip of the bottom part of the 'e' it looks identical to me.

[Horsley-Anarak]

I must ask though, why break such a tidy motor?

I bought it for the tank and cap, other bits are helping other people, SDs are not that rare, I needed a tank for this late ON, the first British Seagull.

More bits will help other people, Tam may even need a power head

H-A

[Horsley-Anarak]

Could it be the same stamp?

[Hugz]

Bump. I now have leg bits required (thanks Tam) but am still after a steel tank if anyone has one preferably with some decal remaining.

[seagull101]

Bump. I now have leg bits required (thanks Tam) but am still after a steel tank if anyone has one preferably with some decal remaining.

Swap a non decal one for spiros