On The Slipway

Nearly all resources of HMS Hood show the layout of the bridge equipment in the open air, though only as location placeholders. One good image is known of Hood’s Air Defence Position (ADP) showing a series of pedestals and smaller sights and range finders. Finding out which one goes where and what piece of equipment it is was the next challenge. In the end, it appears that HMS Hood is fitted with the same equipment fitted to all battleships, most heavy cruisers and fleet carriers. However, getting a good picture of that equipment is something different altogether as these smaller sights are usually placed in crammed positions that are visually obscured.

Here is a unique image of the ADP of HMS Hood. Some equipment is visible and was an unknown to me before starting doing some research. If you want to learn more about how and why the bridge of a British warship was equipped, I suggest reading The British High Angle Control System (HACS) by Tony Tony DiGiulian at the navweps website or the High Angle Firing chapter in the Gunnery Pocket Book at the Historical Naval Ships Association.

The ADP has a control team consisted of the Air Defense Officer (ADO) and his assistant. He has a special ADO sight that can indicate the to-be-engaged aircraft by relaying a target bearing. Such an ADO sight is thus an aircraft bearing indicator but this sight also functions as a star shell sight at night. The other ADO sight is manned by his assistant, so two of these sights are present. There are six so-called Air-Lookouts (ALOs), three on each side of the ship’s bridge. Each ALO continuously observes an arc of the sky around the ship, watching for aircraft to appear. The ALO uses a position with a pair of binoculars. Once an aircraft is spotted and marked by the ADO, the High-Angle Control System (HACS) will determine the target’s speed and bearing so that it can be engaged by the heavy anti-aircraft artillery. Each large capital ship was typically fitted with three or four of such HACS directors. The model of the HACS is described here. Next to the HACS directors, a series of close-range pompom directors are fitted. HMS Hood was fitted with one such director for each pom pom gun, one Mark I and two mark IIs ). The pom pom and HACS directors in the Royal Navy were all fitted with the Yagi radar aerials later, but HMS Hood was sunk before those radars were fitted. One piece of equipment present on other ships that probably would have been fitted to HMS Hood was the Auto-Barrage Unit (ABU) that determined the range of the enemy aircraft, in order for all anti-air guns to fire a single barrage.

Several directors for the searchlights were also present next to these air-defence positions. There is a single searchlight sight per searchlight, but as the two ADO sights can also act as a searchlight bearing indicators, HMS Hood was fitted with four additional searchlight sights.

The captain himself also has a bearing indicator that was placed on HMS Hood, but not on the inside of the bridge probably due to space constrains. On the King George V class, these sights were placed inside. A final sight, according to John Roberts, is a UP sight placed near the upper ADP of HMS Hood. No information was found on this particular sight.

So, the typical equipment found on RN warships is one pair of captain sights, a pair of ADO sights, two pair of searchlight sights (depending on the number of searchlights), three pairs of ALO sights, a pompom director per gun and a number HACS directors. The latter is the only one that is clearly visible on warships.

This image of HMS Prince of Wales’ bridge shows the ADP most clearly. From this picture follows that the sight on HMS Hood’s ADP is the same. The three ALOs are seen clustered together with the pom pom directors fitted a level lower. The searchlight sight (SLS) is just out of view.

A clear top view of the bridge of HMS Duke of York. The three ALOs are well visible. HMS Prince of Wales and HMS King George V have their ALOs clustered together in a single position, but one of the ALOs aboard HMS Duke of York appears to be placed a but further aft. The searchlight sights (SLS) are seen at left below the main fire control director and are wrapped in covers, as are the pom pom directors (PPD). The captains sight is inside the fore bridge and is not visible.

An excellent top view of HMS Queen Elizabeth, clearly showing the six ALO positions and searchlight sights (SLS). The ADO is not visible, but might be located in the fore bridge, as with HMS Warspite (slightly different bridge layout). The ABU is visible bottom right.

A very clear front view of HMS Queen Elizabeth showing the searchlight sights (SLS) and the ABU.

This schematic of the bridge of HMS Victorious shows the same equipment as on the battleships. Even with everything clearly in the open, I haven’t been able to find a good picture of the bridge of a carrier.

Now that I know what to look for, this equipment is visible on most other larger ships and even on monitors such as the layout above indicates, but the quality of most of these images is poor. If you flip through Raven and Roberts Battleships and Cruisers volumes, you’ll notice many (unannotated) positions of the ADP equipment corresponding to the number of directors I now expect on board these vessels.

So, here’s a clear image of HMS Hood showing the location the Captain’s Sight (CS) and UP sight (UPS) as well. This clear image indicates that it is impossible to see any of the items on photographs as described above and the first image in this post of the ADP is the best there is as far as HMS Hood is concerned.

Part II of this post will show the individual units in detail.

The parts of the bridge and fore bridge were already quite finished, until John Roberts posted the sketch below on the official HMS Hood site.

This layout, with a split level, is different from the single (extended)  level in the Anatomy of the Ship series (Drawing E3/5, p86) . Two windshields are visible at the right image (arrows) that support the split-level layout. Note that the right windshield is a bit broader. I suppose this part of the shield can be swung to the side to allow access from the lower platform. The UP-launchers on the boat deck can be similarly accesses by opening the splinter shields. Note the railing at the sides of the air-defense platform (top of the image) below the canvas-wrapped equipment (inside of the arrows). These railings run wider than the roof of the fore bridge and forward position of the air-defense platform. If you look closely, you can see a ladder between the railing and the closed wind shield. The new drawing by Roberts seems to work out quite well with the few photographs of this part of HMS Hood.

The left side of the image shows the admiral’s bridge. The right side is a top view of the new layout. The width of the wind shields is taken from head-on photograph.

As the bridge part was already completed, it needed to be modified for the new layout. The left image shows the inserts I made for the lower half of the split level. This level is quite low, too low for any person to be standing around it. I made this part solid. I have no references whatsoever, but at least it gives the model some support. The right image shows the upper half of the split level. A part with an opening for a ladder according to the old layout was first truncated, then the platform was extended. Note that the bridge part consists of two parts that fit tightly so that the entire bridge can be painted more easily.

A series of voice pipes runs from the air-defense platform. I don’t know where they end up in the platform, nor do I know where the go except for the ones on the photographs.  Note the railing in the top left image, indicating the platform on either side of the air-defense position is as shown top right; with a small 45-degree angle. The bottom part of the image shows the voice pipes in a forward shot and the model. Seems to be a good fit. The damage to the part being dropped to the floor is already repaired! These voice pipes took about 3 hours to add.

The entire bridge and fore bridge as a dry fit. From the photographs it is clear the voice pipes of the air-defense platform run backward, but I can’t see where the are going. All spotting-top voice pipes run toward the tripod, so I decided that all these voice pipes run down under the aft half of the split level toward the tripod legs. The only problem is that they are now partly blocking the door to the compass platform, but I guess they are a bit overscale. Note the opening for a ladder where the split level can be accessed from the admiral’s bridge and the voice pipes at the inside of the air-defense position. This area will be filled with air lookout equipment later to add some much needed detail!

The bridge consists of five separate parts. From the lower deck up, they are: admiral’s signal platform, conning tower platform, admiral’s bridge, fore bridge and spotting top. These decks are placed on the conning tower deck of the previous post in this series. All these decks can be taken apart at any time, so that I can paint the decks and add the stairs and railing before gluing all decks together. It’s really difficult to replace a section, as they were cut simultaneously with all stair openings at the same position (filing all decks at once), so that was never a reason to keep the parts segmented at the time of building. The aft legs of the tripod are now also segmented, and drilling the correct locations was tricky. Once the bridge is completed, a rod can be placed through all parts of the tripod legs for a bit more stability of the parts. This picture is already quite old (2005 at the latest!). As mentioned earlier, this is already the second bridge. The first bridge was made using 0.25mm plate for the decks. This is nice and thin, but it warped a lot. Using 0.4mm seems like a small change but helped a lot.

This is a nice shot of the aft of the bridge in progress. All the openings of all stairs cases are carefully placed. This is one of the details that take a lot of effort and—if all goes well, that is—won’t be noticeable when the model is done.

This is a picture of this weekend, showing the admiral’s deck from above. If you compare this deck with the available drawings, you’ll notice the layout is much different and there is a steel bulkhead around the deck. You’ll notice the scars at the forward left and right of the deck, where the old deck was rudely cut out and replaced with new parts (compare with the first picture). Chances are you have never seen this layout or bulkhead on any other model as this is a recent discovery based on a new picture.

On this composite picture it is clearly visible that the new layout resembles the pictures quite well (from the HMS Hood site). At the top left image, the high splinter shield is seen wrapped around the bridge level. It steps down a bit with an inward step (A). The bottom image shows that this high splinter shield ends just above the 5.5″ control director base (B). The right image shows that the bulkhead is steel, not just covered railings, and that it can be seen that the shield makes a few angles; a small piece of the aft shield is seen at (C). This picture is not new, but I never noticed it.