SS Richard Montgomery

ean_p

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When I started diving in the 70s there wasn't much by 82 I had become seriously interested in wrecks on the South and Cornish coasts and bought a RIB fitted it out with a paper recording depth sounder and a Decca recorder later converted to GPS and very soon after a magnetometer. I photocopied several hundred pages of the British hydrographers wrecks catalogues and spent the winters finding likely targets in the 50 to 60M region ( we used to dive off the old Navy Deep Air tables.) We found some interesting wrecks a lot of which were known to the hard boat skippers of the time but rarely dived. I also found the Apapa off Anglesey and dived it several times a fairly hairy dive, in order to get to know the wreck I bought a set of her build plans from Harland and Wolff, for a long time I had one of them framed hanging in my office at work. The internet no doubt makes it easier now and there seems to be a lot more information easily available and with the advent of mixed gas diving into the amateur market depths are now 100 M and more opening up the field as it were.
Location was time consuming first we got to as close as we could using Decca and then the first uncorrected GPS, drop a shot line and circle or do a straight line grid search with magnetometer and then echo sounder we perfected the technique in locating the James Eagan Layne several miles out in Mounts Bay at 60M then almost never dived but now apparently a popular site. I remember swimming over a line of toilets and seeing one arm of the flying bridge angled upwards which had collapsed the following year when I spent 10 dives over two weeks removing a big brass port light and cover.
Interesting times.
Interesting times indeed. I started with the local SAA club that had two reasonable ribs available when they were running but later formed part of a syndicate of six were we went on to buy a 6.5mtr Tornado with wide tubes and all the toys topped off with 175 Yamaha outboard. The mutts!
Days of gin and days of total blackout with most days somewhere in between as usual! On a good day the east coast takes some beating as it's wall to wall with wrecks of every description and technical ability. On a bad day its not a place for the unwary especially off the head which has its own tidal regime and can be as black as black while running through with suspended silt and endless drapes of micro filament net ! Remember one drop in the early days with one of the old hands, on what on the surface was slack but which when we hit the wreck was just starting to run! The black was total and even his torch which was the old Robin Hood type( a halogen car head light in a solid polyprop casing) was just sucked down to nothing. We hit the bottom and seeing/ feeling the way of things he shoved his face mask to mask with mine put the torch to the side of our heads and I could only just see his gloved thumb making signs to go up, the light having been swallowed up that much. So up we went, a dive lost but an experience won!
In terms of 'meets' (positions in the local tongue) most were down to Decca and then later GPS as it came on stream and often jealously guarded on the less well known wrecks! Admiralty charts were commonly well out and the data sheets for individual wrecks were by that time costing £3 or more per wreck and then only as good as the survey that located them which was often pre GPS and converted from either sightings or Decca. For the inclined to go exploring we preferred to scan the list of fastenings compiled and supplied by the Sea fish authority, which though never exhaustive always gave good food for thought when compared to a chart. If a trawl had snagged then there was something likely to be there especially if a wreck was also shown in the local! Later and towards the end of diving days we came across a survey report of 'obstructions' that probably came from the offshore industry which was prepping at the time to run a couple of pipelines to Norway. That made for some excitement plotting hundreds and hundreds of the obstructions to see if we had any trips into the unknown ! And we did but not that many! Strange but good dives in the area, an area where munitions etc are quite common place include the 1stWW sub laid on top and partially inside of a steamer. Yet the sub sank, if memory serves, about 18 months before the steamer! Another is a heap, a huge heap of cut and dressed stone blocks (harbour wall sized) about 3 miles offshore in about 15mtrs with no evidence of any wreckage of any kind . How or why there there we never found out but always good for a few crabs on the way home if passing! Biggest regret apart from giving the game up in any serious way was not to have dived one of the anomalies that we found by comparing the 'fastenings' to the charts and finding a wreck with no survey data from the admiralty and plotted about 3/4 of a mile from where it really was. Undived by anyone as far as we could find out and plotted by us after spending a day tolling around with the fish finder. sat in just over 50mtrs it had a very small footprint but rose up sharp, if memory serves, about 17mtrs off the sea bed. X1 we christened it but never had the opportunity to dive on it ! maybe still there untouched!
Good days!
 

Norman_E

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This is what can happen if you detonate a ship load of HE. Halifax Explosion - Wikipedia
Also look up the Fort Stitkine SS Fort Stikine - Wikipedia
The latter ship had about 1400 tons of various explosives on board, which is about the same as the Richard Montgomery. Before the main Fort Stitkine explosions quite a bit of its cargo had been removed and some had been destroyed by minor explosions. Despite that two separate major explosions caused considerable devastation.
 

trevbouy

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I can't find the article now but I remember there was a report of an individual being intercepted by the Navy(?) in an inflatable carrying home made explosive devices which he intended to "set off" the Montgomery.
I believe he was detained under the terrorism act.
I can only assume they had intelligence of his actions given that one random boat heading out that way like others would attract immediate attention.
Anyone remember this?
 

oldgit

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I can't find the article now but I remember there was a report of an individual being intercepted by the Navy(?) in an inflatable carrying home made explosive devices which he intended to "set off" the Montgomery.
I believe he was detained under the terrorism act.
I can only assume they had intelligence of his actions given that one random boat heading out that way like others would attract immediate attention.
Anyone remember this?

Not that long ago it was not unknown for small craft with crews very partial to catching and selling Bass into the retail market to be discovered actually inside the bouys.
 

Greenheart

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Surely HW would be far worse?

The depth of water at HW wouldn't encapsulate the energy of such a huge explosion so there'd still be a window-breaking shock-wave; and the water-wave created on top of HW level, might flood anywhere less than a couple of metres above the HW mark for some distance.

Isn't it a question of the medium that carries the energy? And the relative solidity of water makes it far more damaging as a moving form.

Must admit, I have exactly no idea.
 

oldgit

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From a non sciency person .
Air pressure sound wave would cause less physical damage but travel further , the energy in water would cause more damage in a more limited area. ?
 

Stemar

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Tsunamis travel huge distances before doing damage, so I'd have thought (no science behind it) that it would be the other way round. The shockwave in the air would be dispersed in a hemisphere, but the water is a much smaller volume.

Either way, I don't want to be anywhere near it - I'll let someone braver than me video it and I'll watch on Youtube!
 

Motor_Sailor

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On the Cornwall TV program last night, I'm sure the guy from OS said they can detect Pacific tsusamis at their tidal observatory in Newlyn.

From that, it would appear waves in water travel amazing distances.
 

Thistle

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On the Cornwall TV program last night, I'm sure the guy from OS said they can detect Pacific tsusamis at their tidal observatory in Newlyn.

From that, it would appear waves in water travel amazing distances.

Sound waves travel well in water - whales communicating, echo sounders, sonar, etc - so I'm not sure we should be surprised by this.

My suspicion would be that, because water is much less compressible than air, an impulse through the water would have the potential to create damage over a wider area than one travelling through air. This has to be balanced against the fact that there are fewer structures in the sea than on land so we are likely to be less aware of underwater damage.
 

Greenheart

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Hopefully there's a nice accurate schedule, so one can arrange to be there when it all goes up, and surf to Southend on the tsunami.
 
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