Topic: WW2 floating dry docks (Read 8123 times)

Brian60 · « **on:** May 14, 2016, 07:24:11 pm »

I came across this link today, it may of interest to some warship modellers

https://www.warhistoryonline.com/military-vehicle-news/massive-floating-dry-docks-of-the-pacificfleet.html?utm_medium=social&utm_campaign=postplanner&utm_source=facebook.com

warspite · « **Reply #1 on:** May 14, 2016, 07:35:42 pm »

Didn't they used to have something like this off the coast of Scotland for American subs to refit, years ago, probably during the late end of the cold war?

Netleyned · « **Reply #2 on:** May 14, 2016, 07:46:29 pm »

That's right.
The RN had some up to the 60's.
They were numbered with the prefix
AFD. Admiralty Floating Dock.

Ned

deadbeat · « **Reply #3 on:** May 14, 2016, 08:34:45 pm »

AFD26 was still in use in Portsmouth into the 70s. AFD29 broke in two with HMS Valiant, the battleship, in dock at the time. This was due to poor weight distribution as they didn't take into account full magazines.

ballastanksian · « **Reply #4 on:** May 14, 2016, 08:50:39 pm »

That's right and it ended her active career as two of her shafts was badly damaged. She was patched up and sailed in this state to Suez frames off before she sailed to the UK and bcame part of HMS Imperieuse, a Stokers training est along with two Revenge class battleships and Renown.

In a way it would not have made a difference to her end if she had not suffered the damage as she would probbly have been broken up in 1947/48 anyway

tonyH · « **Reply #5 on:** May 14, 2016, 09:18:18 pm »

There's a great book, Jutland to Junkyard, about the raising of the High Seas Fleets from Scapa and how one of the docks was butchered and used in the job.

ballastanksian · « **Reply #6 on:** May 14, 2016, 09:19:55 pm »

I mean to get that book one day as it is a gem.

Colin Bishop · « **Reply #7 on:** May 14, 2016, 10:25:30 pm »

Southampton had a floating dock in the 20s & 30s that could lift 60,000 tons. It was used for many of the largest liners such as the Majestic.

http://www.shippingwondersoftheworld.com/floating-docks.html

Colin

littoralcombat · « **Reply #8 on:** May 15, 2016, 03:13:38 am »

There was an AFD at Devonport moored in a corner of 5-Basin used primarily for Oberon refits, I remember it being there in the late 80's. A couple of Leanders used it as well when other Dry Docks were unavailable.

Nige

Arrow5 · « **Reply #9 on:** May 15, 2016, 09:06:38 am »

Quote from: warspite on May 14, 2016, 07:35:42 pm

Didn't they used to have something like this off the coast of Scotland for American subs to refit, years ago, probably during the late end of the cold war?

This dock was the Los Alamos based on the Holy Loch near Dunoon. The "Polaris" submarines of the U.S.Navy were based there.

derekwarner · « **Reply #10 on:** May 15, 2016, 09:32:11 am »

We had one of these at work & yes left over from WWII [but only rated to 800 tons]

I declined to board it as every two weeks or so it appeared to have sunk

............. Derek

deadbeat · « **Reply #11 on:** May 15, 2016, 12:41:47 pm »

The last floating dock built for the RN was AFD60 which was built in Portsmouth in the mid 60s, she was meant for Polaris subs and went to Faslane.

Jonty · « **Reply #12 on:** May 15, 2016, 10:16:26 pm »

Catching the ferry to Orkney a few years ago, one was being used as a breakwater.

tonyH · « **Reply #13 on:** May 16, 2016, 10:32:21 am »

That's probably one of the ones used in the Scapa lift.

wbeedie · « **Reply #14 on:** May 21, 2016, 12:56:57 pm »

There used to be one in Lerwick years ago, dont know what it was originally for but not a big thing, mostly used by fishing boats in days gone by, remember seeing it early last decade

kiwi96 · « **Reply #15 on:** May 27, 2016, 07:00:13 am »

I have thought of building one of these for my ships. Where would I look to get plans. Be great to have in pond with the ships.

Akira · « **Reply #16 on:** May 29, 2016, 12:10:37 am »

You might try the Floating Drydock, here across the pond . They carry a set of plans. Scroll down to Auxillaries. First line.
http://www.floatingdrydock.com/G.htm

warspite · « **Reply #17 on:** May 29, 2016, 10:20:02 am »

It's like one of those Marlin submersible vessels - controlling its rise and dive would be essentially the same.

Plastic - RIP · « **Reply #18 on:** May 29, 2016, 03:31:35 pm »

I would have thought this would be a really challenging build - first it is a catamaran with 2 hulls deep in the water so it would be very stable.
As you pump air into the hulls, the centre of gravity will rise as the side tanks empty.

As the weight of the ship in the dock bares down on the bottom of the dock, the centre of gravity will rise a lot more until it is just the dock base in the water.

As you pump air into the base, you are making a large, unbalanced raft with all of the weight way above the water surface.

Be interesting to see how that behaves.

derekwarner · « **Reply #19 on:** May 29, 2016, 10:52:53 pm »

On that old Dry Dock at my work that I did not board

....well each of the different chambers were vented to atmosphere.....water was gravity fed, then pumped in or out

.......the only air involved was to mother nature...........

If building, consider quite a number of internal baffles for stability and quite a lot of hand wheels in the very topside levels...........Derek

Akira · « **Reply #20 on:** May 30, 2016, 03:18:59 am »

Interesting video relating to this subject. Notice the large and wide pontoons supporting the dock walls.

https://www.youtube.com/watch?v=GD2rM4RjUEY

warspite · « **Reply #21 on:** May 30, 2016, 12:43:01 pm »

Well they were constructed as sections, transported with the walls flat packed onto the pontoon, when at their final destination the sides were lifted and the sections welded together to form the whole dock, feat of engineering on a grand scale.

Akira · « **Reply #22 on:** May 30, 2016, 01:21:04 pm »

In my opinion, this coming from a submarine modeler as well as a builder of targets, the problem of balancing a drydock is two fold. Lengthwise, the dock must be made in sections and and controlled as such, using independent valves( solenoid valves?) and either pumps or pressurized air. The real area of concern, though, is lateral control. This can be a problem because centering and holding the "ship" on center line while "pumping" the dock becomes problematic. I appears that the dock would require independent lateral control as well.
Bear in mind that the set-up of keel blocks in a dock was a very precise affair and was specific to each ship. I think a model would tend to lend itself to flat bottomed vessels rather than, say, a nicely rounded hulled tug.
All this said, it certainly could be done and I would really enjoy seeing it.
I have a U.S. Maritime Commission V-4 tugboat, which I scratch built, and have often toyed with the idea of building a submerging and surfacing Phoenix, with which Which I could tow to the Normandy Beachhead.

Plastic - RIP · « **Reply #23 on:** May 30, 2016, 03:36:57 pm »

Assuming a flat-bottomed ship model, I'm thinking you would need a couple of Vee blocks on the base of the dock- one to nudge the bow into to centralise the front of the ship and another where the stern could slide down into - it could be motor-driven for length adjustment so it could accept most models.

If someone fancies building one, what scale do you think they should go for? 1/96? 1/200?

Akira · « **Reply #24 on:** May 30, 2016, 05:26:38 pm »

An answer to your last would depend upon 1) the scale of the vessels to be lifted, 20 the amount of internal workings one would want to incorporate. While 1/96th would/could make for a large dock, it would, at the same time, allow for far more internal mechanics and may even make the assembly and transport easier.
How about an ARSD suitable for an Iowa or KV 5?

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Author Topic: WW2 floating dry docks (Read 8123 times)