Page 13 of 28

Booms, davits and derricks, part I

January 19, 2013 / efoeth

There are many booms, davits, and derricks scattered around HMS Hood’s decks and superstructure. The rigging and davits are drawn up in excellent detail by John Roberts’ Anatomy of the Ship: HMS Hood and Anatomy of the Ship: HMS Dreadnought. A full list of booms and derricks is given in Maurice Northcott’s HMS Hood: Design & Construction (Ensign Special or Man o’War, same content). Together they have nearly all the information we need for the 1941 version. From the images can be concluded that some booms are tapered, but derricks are not. All booms and derricks are wooden, except the main derrick.

Here you can see a paravane being deployed or recovered (A), but this is not the paravane derrick. This derrick is operated next to A turret, while the actual paravane derricks were stored directly aft of the forward breakwater where a pair of paravanes were stored (B). You rarely see these derrick deployed though and if you want to add them the best option is to either model them lowered (C) or not at all (D); Most images of the forward breakwater show the derricks to be absent. So, if you build the Trumpeter kit you’d best throw these parts away.

The second largest set of derricks consists of three pairs of 40ft derricks. These derricks were used to load ammunition or hoist boats. When HMS Hood was completed, one set was stored near the bridge, one set was fitted to the smaller cranes on either side of the funnels, one set was stored at the deck side on either side of the main derrick and one set was stored to the quarterdeck (4 pair). For the 1941 version, two pairs of derricks were fitted to the bridge bulkhead, below the smaller sounding booms, while the other two sets remained fitted to the smaller cranes. The quarterdeck derricks were removed.

Another set are the 36′ 9″ sounding booms. No resource specifically identifies their location, but two booms of the same length were fitted above the 40ft derricks during the final modification. This indicates that the sounding machines themselves were on board when HMS Hood was sunk. The image shows the sounding boom deployed during outfitting (A). Two sets of booms are fitted for embarking and disembarking. One set of 50ft guest warp booms (A) was fitted to the hull near the bridge and one set of 30ft6in swinging booms was fitted at the quarterdeck bulkhead. These booms were all tapered. Note how all these booms were rigged with a stay and two lines.

The swinging boom near the quarterdeck bulkhead is very difficult to spot in photographs taken during the war. The stays are easier to spot (A), even though the boom is not (B). Note that the 40ft ammunition derrick at (C) was removed when the air intake in the quarterdeck bulkhead was covered up (D). The stay for the swinging boom is still present in the image bottom right.

The largest derrick is of course the main derrick operated from the main mast. Here you can seen the main derricks aboard HMS Rodney (left), HMS Inflexible (top right) and HMS Hood (bottom right). The style of the main derrick appears the same for all capital ships and the drawing in the Anatomy of the Ship: HMS Hood is not accurate. There are small changes in the rig of the derrick between ships and the hoist line does not loop back the same number of times for all ships.

The flange couplings of the main derrick were simulated with tiny triangles added with a very fine pair of tweezers. The pully in the end of the derrick was added as well for proper rigging. The start point of the derrick was ‘milled’ into shape with the cross table of the drill press.

The support on the main mast was built from plastic plate; you don’t always need photo-etch to make such difficult to make shapes (even though I should have).

The list comprises of

1 65ft main derrick (1)

2 50ft guest warp booms (2)

2 30ft 6″ swinging booms (3)

4 40ft 4t ammunition derricks (4)

2 40ft 5t boat & ammunition derricks (small cranes) (5)

2 36ft 6in sounding booms (6)

2 12ft paravane derricks, mostly stored

Northcott lists one 8ft derrick present as late as 1931, but I haven’t been able to find any image, so I guess it was stored out of sight with the paravane derricks?

Most work on the derricks was spent adding small rings!

The smaller davits will be treated in a small follow-up post.

Carley Floats

December 30, 2012 / efoeth

I started these Carley floats about a year earlier while we were in the middle of rebuilding our house leaving little space for any modeling (the model was stored). The floats didn’t require the model to be at hand for fitting and I wanted to do something. So, some time for minor parts. Ahston et al. (1993) published a thorough investigation on the loss of the HMAS Sydney and a related Carley float; one float was apparently the only remnant for HMAS Sydney, a cruiser lost with all hands after a battle with the German auxiliary cruiser, HSK Kormoran, in November 1941. This report contains a bit of particularly useful information.

The Carley float is a simple combination of copper tubes with a cork, cotton, and canvas covering. A wooden grating that could be lowered in the water was fastened with rope where you could ‘stand’. The even less fortunate were expected to cling on to the ropes around the float making it not much more than a large life ring for groups. I can image you can only survive with such a float for a few days when the weather is favorable. Note the characteristic way in which the rope is wound around the tubing, showing rope going around the entire float and around the circular section, but also rope at an angle at the inside. I wanted to capture this specific detail. Before starting, I had to know which types of float were carried by HMS Hood as the exact dimensions of the floats weren’t written down anywhere I looked. Ahston et al. give a table of the types of rafts available at the time:

No Size Tube Diameter
5 3ft 6in x 6 ft 12in
6 3ft 9in x 6ft 6in 13in
7 4ft x 7ft 14in
8 4ft 6in x 7ft 6in 14in
19 5ft x 8ft 14.5in
20 5ft x 10ft 15.5in
14 6ft x 10ft 16in
15 6ft6in x 10ft6in 17in
16 7ft x 12ft 18in
17 8ft x 12ft 19in
18 9ft x 14ft 20in

It is noted that each float was fitted with two paddles (four for No. 18), a boat hook and a painter (?); No 16 to 19 had two ladders. This is information as precise as one could wish.

This image shows two Carley floats hanging from a few ropes to the bridge bulkhead and, based on its relation with the bridge structure it’s suspended from, I’m quite certain it has to be 5 feet wide based. Note that the ropes differ from the pattern usually observed: there should be some rope at the center of the float but it’s not. I haven’t seen a single image of a float with the pattern as seen here so I guess the crew repatterned the float? This detail was omitted from the raft models though.

I found out that the closest matches are Nos 19, 20, and 17. The Nos 19 are fitted against the bridge superstructure and on the disinfector house, No 20 is on the superstructure between the funnels and fitted to a side bulkhead of the aft searchlight platform and No 17 is mounted against the aft bulkhead of the searchlight platform. The position and number of floats aboard HMS Hood seems to differ greatly over the years, but I think this is fair assessment of what float goes where for April 1941. Note that the floats to the port side of the forward funnel appear to be lying on some structure. Instead of worrying about the type of Carley float, the real question is: what is this structure? More about this later below.

The model floats themselves were made from styrene rod. You first need to bend the rod into shape. I played with boiling them, putting the parts in the oven and I eventually used a cigarette lighter on rod curved around the end of a drill with the right diameter. You only need to heat the part for a fraction of a second or it will melt or start to burn. Each float consists of two halves that do not have a tendency to bend back. Next, I used the drill press to make a drilling jig. At left you can see the outlines with a few 0,3mm drills. I glued thick styrene strip against these drills, let it dry, put in the floats and drilled away. I used the cross table of the drill press for a reproducible pattern. The result is a series of drilled-in rings, here for the 5×10 models.

The rope pattern can be simulated with brass wire. Gluing small pieces along the raft gives a lot of glue spots and doesn’t really look very good. So, thought it would be nice to sow the ropes with 0.1 mm brass wire. The real Carley floats aren’t very neat, so making this rope pattern by hand gives with the same variation. Here’s an example of the largest float so that you can actually see how these floats were rigged. I started with gluing the end of the wire to the inside to the float, out of sight and not clogging up one of the holes (1). I then went around the float, zigzagging from point to point. The procedure is reversed and the cross pattern in the ropes appears (2). You constantly have to correct the wire with a pair of tweezers or push the wire through the hole with small drill to get the best result (3). Simply pulling the wire taut every few runs doesn’t give a good result. Sometimes the wire breaks, but repairs are easy to do.

After the cross pattern was made I continued with the other ropes. I jumped from one hole to the next over the top surface of the float and put the wire through the hole (4). I went round the float once (5) and before pulling it taut, I ran the wire back through the hole, ending where I started (6). The wire around the float lies on top of the wires going from hole to hole, kept neatly in place. In the end, a single wire produces the entire pattern and runs 4 times through each of the 0.3mm holes. About 15cm/6in of brass wire is needed for the smallest float. Glue is added afterwards, at positions that are mostly out of sight. Even though this was fun to do, I wouldn’t recommend making all the floats by hand for a project where you need fifty floats. Next time I’ll cast a few for easy reproduction.

Now for that mystery block near the funnel. In the top left image you can see it hiding in plain sight and you really have to look closely or you won’t notice it is there at all. Top right shows the floats stacked on “it’. It appears to be fully closed. So, with no more to go on, what could it be? Other ships have similar blocks. For instance, there are two of them on the boat deck on the King George V class battleships, shown bottom left (plus Carleys on top of it). Notice there’s a lot of planks and beams sticking out. Now, HMS Hood also carried a lot of planks and beams next to the funnels, deposited loosely and without any structure, so it might just be a neater and safer way for storage. On either side of the turrets of HMS Rodney (bottom right) you can find similar racks. These are shorted and appear to be oars storage racks? I cannot tell for sure for HMS Hood. I decided to add a randomly detailed rack to HMS Hood, based on the dimensions in the above images.

A second wire going around each float was added next. These wires are fixed with glue only and are not as ‘sturdy’ as the first wire. Some of the 5×8 and 5×10 floats were stacked. For the lower floats, on the wire you can see is actually added, not the complicated pattern.

The largest float is glued directly against the aft searchlight platform; there is some room between the etched grating and the outer ring so both are glued separately. One 5×10 float is also added, leaving just enough room for the door below it to open.

One other type of float is present aboard HMS Hood: a series of Denton Rafts. The top left image is of HMS Hood, showing the 16″ dinghy, two 5×10 Carley floats and a few Denton Rafts. The image right is the only other image I managed to find. The rafts were made from a simple piece of PE, glued to place usng a small template for easy centering. I have over 20 of these rafts to be added randomly on the structure between the funnels.

1) Ashton, J., Challenor, C., & Courtney, 1993, R.C.H., The scientific investigation of a Carley float at the Australian War Memorial, Technical Papers of the Australian War Memorial, No 1

UP launchers, part II

December 24, 2012 / efoeth

My UP launchers were destroyed after receiving a coat of Vallejo primer, a primer that did not stick to the resin or the stainless steel photoetch. I designed new etched parts for the launchers and started all over.

I made a small sketch based on John Lambert’s drawing and I added a few modifications (The drawing by Lambert is based on photos, so I guess that’s fine). I thought it would be easy to repeat these models but these launch tubes were very difficult. The launch tube is a styrene core with a PE part wrapped around it. The styrene core really needs to be accurate with 0.1mm or the PE parts will come off when held in the calipers when drying or in the vise of the drill press. Then the PE part itself needs to be folded accurately. Somehow I thought it would be better if the PE part had 8 folding lines instead of 4, to capture the correct form of the launch tube with the 45-degree edges. Then you need to drill in all the tubes. I reread my previous post where I read I had to make 30 parts before I had 5 good parts. This time I didn’t no any better. I fear the Proxxon cross table and the cheap drill press isn’t any good resulting in poor reproducibility (a few hundreds of a mm will show up easily in this closely knit pattern). Also, the front of the launcher part has to be completely smooth or the drill will wander. This is why the styrene core is built up from strips but with a single flat strip glued at the end; this really helped with getting a consistent pattern. One major consumer of hobby time when using the drill press is finding a reference point, or zero. I ruin 2 or 3 parts before I find the correct position so I need something better. Trying really hard doesn’t cut it! After a while you’ll find the entire pattern lined up nicely in the center of the launcher. Two conclusions. One: I need to learn to cast properly to avoid making all these difficult parts over and over. Two: I need a proper drill press with a cross table or CNC milling machine to punch in these difficult patterns.

So here they are, the low yield of several days of trial and error. I did manage to make the gunners viewport open which is an improvement. There are also 12 large ammo lockers and 8 small ammo lockers, one set for each launcher except the one on B-turret. I do not know where they stored the large ammo locker.

And just for fun, all the parts I have made that didn’t work out!

Custom Photoetch Set Part VI

October 24, 2012 / efoeth

Another etch? Well, the design I showed in part V was fine, except that I’d used very dark gray instead of black in Illustrator. A nice dotted pattern was visible over almost all the parts. The railing were fine though and only a few parts were repeated.

With only a few parts and an A5 area to fill, I could place a ‘spare’ set on the other side. The UP launcher parts and some gratings for the bridge floor were drawn in three versions as I experimented with different line thicknesses for the mesh from 0.05 to 0.075 mm, the smallest working just fine (not entirely etched through everywhere, but that’s not visible to the naked eye when the model is done). The hawser reels can now be redone (sigh) but at least I can now solder them. The rest are spare parts and I added the stairs so I now have brass versions. The etch was again made by Hauler; there was less than one week between submitting my order and delivery of the etch!