Torpedo net rigging

mfsob

A bit of historical trivia, some Liberty ships in WW II were fitted with torpedo nets, but they were dirt simple things compared to what was on the WW I capital ships, and I have no idea what they were made of. You could spot the Liberty ships that carried them because one sent of cargo booms forward and aft was longer, to stream the nets out away from the hull on each side. They didn't even cover the entire hull, just the vital center engineering spaces. A few (not very good) photos, of ships with the telltale longer booms and the nets deployed:

Interesting!  BTW, I built the Trumpeter Jeremiah O Brian 1:350 kit.  That was a very nice kit.  No torpedo nets, but everything else. Used someone's PE package- I think it was Tom's Modelworks.  Anyway, it was a great build.

A bit of historical trivia, some Liberty ships in WW II were fitted with torpedo nets, but they were dirt simple things compared to what was on the WW I capital ships, and I have no idea what they were made of. You could spot the Liberty ships that carried them because one sent of cargo booms forward and aft was longer, to stream the nets out away from the hull on each side. They didn't even cover the entire hull, just the vital center engineering spaces. A few (not very good) photos, of ships with the telltale longer booms and the nets deployed:

Anchoring by the stern is a unique thing.

It has its uses, though.  Even if a "Mediterranean Moor" has few applications for capital ships.  Though, in earlier times (like the pre-dreadnaught GB) it was not uncommon to rig a second anchor windlass/capstan aft.

Barring ships with a reason for a stern anchor mount--like an LST, that stern location anchor is for the convenience of rigging a stream or kedge anchor.

Such rigs look, in plan view like an "L" or a "7" and are used as a way to keep the scope (length of rode:depth of anchorage) but also control the swing of the ship at the end of that scope.

So, what you do is to run out the anchor to its scope.  While you are at that, the rest of the Sea and Anchor Detail will pay out either the unused anchor chair (or unhitch one of the other anchors to hang on its chain stops).  This chain is flaked out on deck in sufficient  length to reach that stern-mounted anchor   The anchor would be hoisted out with a davit, gin-pole, or the like.  

While this was evolving, the folk on the bridge would steam the ship around to where the kedge/stream anchor needed to be set.  At which time the Bridge will call to lower away that anchor.  The scope on the stream anchor would be paid out, then everything would be stoppered and made fast.  At which time steaming operations could stop, and the flags broken out for mooring.

Digging out my 1938-published Bluejacket's Manual, it reminds me that stern anchoring can be done with a wire line of sufficient dimension.  That such a need could occur if mooring in river channels or where tidal bores exist.  The anchor(s) would set up-current, and the stern anchor put over only to control the swing of the stern.  Rather than pay out extra rode forward and set the stern anchor, you rig the stern anchor to one or more of the ship's boats, which would motor to where the stream anchor ought go, and place the anchor that way.  

There is a great deal of precautionary language about not merely manning the capstan/windlass constantly, but also to insure that the snipes kept steam available for the winch in similar constancy.   Further, that the hands ought be cautions not to rely upon the brakes of the winch, that any stoppers ought be only of the best manilla well fitted with strops.  And, that  such stoppers  could be rigged to the other gypsyhead of the winch.

Much of which would be an absolute bear to model at 1:350 <sigh>

Thanks, Scott.  Someone else from the group here scanned and emailed me the diagrams from that book.  They answer most questions.

Don,

In his book "Anatomy of the Ship, The Battleship Dreadnought" (ISBN:085177895X) John Roberts presents the torpedo net defence in two pages of line drawings and how they were stored and deployed on pages 214 and 215. The net is a series of 2.5" interlocking steel rings and is controled by two sets of wires. One to deploy and recover the net and the other to deploy and recover the booms that held the net.

Scott Harris

Thanks,   A couple of added words made a big difference on the search results.  Even found some detailing nets on Dreadnought!

CapnMac82

Oh, and since it's likely in a moored state to have the nets out, probably would be good to have the boat booms and companionways rigged out, too, if on the other side of the ship.

Yep, the Pontos detailing set has beautiful boarding hardware, and boat booms.  Brings up the question of how the aft anchor is rigged.  There doesn't seem to be the same type of heavy line/chain handling hardware there as on the forecastle, but I have heard that moored or at anchor in a port there were both bow and stern anchors deployed, right?  I chickened out on my recent build of the Olympia and ended it displayed not at anchor, but would really like to try the Dreadnought anchored.

E-mail sent yesterday, hope it got through.  I also found a description of how it was deployed which says the nets were unfurled first, then the booms swung out when deploying them.  I can send you more details if you like?  There are around 12 small pages of description with a few illustrations.

If you google "shipboard anti torpedo nets" you will find a wealth of information and pictures. It appears the nets were made of iron rings and weighed 5 lbs per foot. The booms were 40 feet long. I their stowed position the booms laid along the side of the ship at around a 30 degree angle. The net itself was rolled up and stowed on a shelf that was outboard of the lifelines and other on deck equipment.

Oh, and since it's likely in a moored state to have the nets out, probably would be good to have the boat booms and companionways rigged out, too, if on the other side of the ship.

From long-ago recollection, the torpedo nets were heavy--thing baseball backstop, not golf ball capture net.  So, the netting was to be like an AFV's Schurtzen, except that instead of a 2kg rpg at a bare hundred meters per second, a torpedo is a couple of tons ate 30-40kts.

This is not a casual weight to heave across the deck and lash outside the rails until deployed.  I want to remember a bon mot about how every navy in the world tried every way to rug torpedo nets, and they all works so well that adding bulged hulls was simpler and cheaper.

I have this nagging rememory that one way to rig the nest was to sweep all the booms against the hull.  Then get the net outboard of the lifeline, then fasten the top of the net to the booms.  After which you lowered the booms down to their topping lift limits, then swung the whole mass out by training the booms around on their guys/stays.

I remember (if only vaguely, it having been an epoch or six ago) in ship stability class hearing about rigged nets as a special case example of atypical moment arms affecting stability.  They certainly would not help ship handling at all.  I want to remember that doctrine was to only rig the nets at moorings, and then only on the vulnerable/most likely threat axis side of the ship. 

Thanks- I'm sending you my email seperately.  The davits supplied in the Pontos set are called  brailing davits, so I guess those would have a line from the tip of the boom down around the bottom of the net and up to that davit.

I had a look at the AOTS book and it is complicated, especially to explain in text.   And it is different to what I described.

The booms don't appear to be horizontal when deployed, slightly downhill.  The brails (lines to furl and unfurl the nets) are not one per boom, but packed closer together.  The direction of the brails changes as you go forward from the ship from the stern and is really too complicated to describe.   The coal winches used for the brails are the ones just forward the main mast, the ones on the aft bulkheads of the superstructure (just forward of X turret) and the ones on the forward side of the bulkheads on the forward superstructure (if that makes sense)

The capstans are used to deploy the booms..

If you send me your e-mail, I'll try to send you something.

John.

Hi Don,

I don't have the book with me, but I'm sure AOTS Dreadnought will have a description of the rigging and the location of the winches used.  

From my experience with earlier ships, the torpedo net booms were rigged with 2 fixed ropes (sometimes three) so that when the boom was lowered to the horizontal, it made a stable tetrahedron with these two ropes.  The ends of the booms furthest away from the ship were connected by a rope that went from bow to stern.  The booms were deployed and retrieved by pulling on the appropriate end.

The net was like a roman blind, with a rope at each boom to furl and unfurl it..  The net could be attached to the rope going between the booms or to a rope suspended below it.  

Here is a website that explains some of it.

www.cityofart.net/.../albion.htm

I read an account that stated that there was always something that went wrong, a rusty joint, a snagged rope, but it was something that the (British) officers enjoyed making the crew do.

From this site

http://www.russojapanesewar.com/russell.html

It reminded me that Dreadnought had a more complex system than I am used to.

I'll check the AOTS book when I get home and let you know better.

John