The Ship Model Forum

Read a few more books on the subject please.

I agree with you Guest. Obviously heeling out of her turn; you can also see the wake curling off to the far right cropping of the photo.

_________________
IG: @somewhere_east_of_suez
www.JosephReindler.com

Effect of a turn is part III of my research question. Perhaps the roll towards the enemy adds a few degrees that make deck penetration more and submerged hits less likely? When part I is finished and pending part II actually happening (effect of sea keeping sailing a straight line).

Hello again Guest,

Apologies for repeating myself but concerning wake form I am really only interested to understand exactly how HOOD would have appeared in her final turn - because I am a maritime artist and I am just finishing a painting of exactly this, which I only want to ensure is as accurate as I can possibly make it..

I would agree with you that the midship trough probably mattered little given the diving shell which found its way into POW, as you correctly point out. In defence of Drachinifel however he did present an argument whereby a shorter distance of underwater travel may have resulted in a higher probability of the fuse actually arriving intact and triggering.. I am neither agreeing or disagreeing with this theory - which is probably academic anyway given that nobody will ever know exactly what led to the demise of this beautiful ship. I think that the theory, while obviously novel, stands as nothing more than an interesting piece of conjecture against the myriad of other equally credible possibilities. Personally I am just as inclined to believe the 'dreadful fluke' was achieved by something more akin to a Kennedy bullet - given that the kinematics and inherent instabilities of high energy collisions are very given to a shell actually changing direction after it enters a ship. We know this for certain from damage reports from surviving ships describing heavy shells crashing through and changing directions several times before eventually coming to rest. But again, this is also just conjecture.

With respect to your anecdote about "something arriving early in the action" - was this not just a reference to the boat deck fire observed on HOOD's shelter deck? I recall there was another eyewitness report from POW (Captain J.C. Leach?) which mentioned HOOD was hit badly and was likely out of action, by this same series of events resulting in the R/U ammunition fires on HOOD's boatdeck [which were actually non-critical] ..

Given the variance across surviving accounts I would heavily doubt that everything that happened, especially concerning fall of shot etc, was actually witnessed in the final seconds.

Lastly, concerning sea state and wind etc - I think a Beaufort 3 from Starboard with slight swell was correct. "A grey sea under a grey sky".. Ted Briggs also mentioned some swell and enough of it to wet the upper decks at speed. I agree not enough to affect ship speed; and that photographs from the German side don't appear to show a high swell - however this can be difficult to judge given that the ships involved were obviously very large.

Regards,

Joseph

_________________
IG: @somewhere_east_of_suez
www.JosephReindler.com

I agree and I think the 12" armour strake should have been deeper notwithstanding any trough.. but then there is another argument floating around that ships will initially roll into their turns, on account of the centre of effort of the maneuvering force i.e.: rudder or pods etc being at negative eccentricity from metacentric height - before the centrifugal force of topweight above metacentric height takes over and rolls the ship out of her turn. Personally I have never seen a big ship do this. Perhaps there is a very minor effect there - but I never witnessed it. Vividly recalling a while ago now when I helmed an 18,500MT capital ship in a perfect flat calm down the Irish sea and executed some turns.. the horizon always banked one way (out of the turn) and never the other way first. Those armchair navarcs eh (perhaps the effect is relevant to lighter vessels...?)

_________________
IG: @somewhere_east_of_suez
www.JosephReindler.com

The rudder imparts a force opposite to the direction of turn and as that force is applied very low there will a small outward moment around the longitudinal axis. But from what I can find from tests/calculations the effect is very small? Theoretically present

My experience underway with Essex Class carriers, which definitely have a lot of top weight, is that there is a very considerable outboard roll in a turn. Perhaps less with a Battleship, but noticeable at speed. Hood and POW made fairly small turns so would have lost little speed. Serious maneuvering such as in avoidance of bomb or torpedo attack can cause considerable loss of speed which can take a lot of time to work back up to full speed.

Some analysis that I have read believes that the fatal shell may have penetrated the upper 7" belt and then the deck, presenting some geometrical analysis of the calculated angle of fall etc. My recollection (subject to error) was that potential turn induced list was not involved in the calculation.

As to the sea state it was enough to cause Holland to leave his escorts behind. My recollection (again with caveats) was that the shell hit on POW below the waterline was discovered in dockyard, the unexploded shell in the bilge. The shells that hit the compass and director platforms also passed though without exploding, though splinter damage caused considerable casualties. The British actor, Esmond Knight, who played Captain Leach in the movie Sink the Bismarck was injured in the actual battle by the shell hitting the AA director platform, loosing the sight of one eye.

Hood was if nothing else a very comely ship and showed the flag for two decades with great success. Certainly her speed and armament figured into Kriegmarine's strategic calculations much in the way the Japanese Kongo's figured in as Japanese carrier escorts in US planning before the war, before the fast battleships became the operational norm.

I agree that it's easy enough to resolve a rolling moment acting in this way; however: against what extent of inertia and non-rigid body torsional dampening? and also: in phase or out of phase with roll period? I'd actually doubt that, for a heavy warship at least, there would be a measured effect at all. Perhaps it is relevant for small light passenger ferries etc, but not for large warships. It would also only act very briefly until the rudder took effect and the ship began to turn.. and there is probably not a large enough lag in there for it to have a pronounced effect? Put it another way I never saw the horizon wiggle the opposite way between the conning order execution and ship heading actually starting to change..

_________________
IG: @somewhere_east_of_suez
www.JosephReindler.com

The point is not necessarily the turn, it is that at the speed Hood was traveling, there is a trough formed at the main mast area that if a 10 to 20 foot short shell, could have its trajectory flattened by the sea, but would not have its momentum slowed down enough to keep it from punching through the bulge below the side armor, it would or could have set off the magazine. I don’t know how to add pictures from previous posts, but if you go to page 47 of this post, there is an entry by “dick” that has a closeup of this wave trough.

Hello All,

We do know from study of the wreck that Hood had her rudder over and was at some unknown point of a turn. I believe ships pivot about a point approx one third of their length and so they 'slip and heel' or skid accross the water and lean as they do so.

For example in gunnery calculation this is a problem, but the table in Prince of Wales could account for the ships slip and heel as she turned, however I'm not sure Hood's Dreyer table could do the same and so according to Admiralty firing manuals small course movements were advised which may account for the gradual 20 degree turns?

There are numerous witness statements about the loss of Hood most of which are contradictory, some say they saw two final hits, some one, some put the boat deck fire and explosion as being close in timing, others give a separation, so to decipher all of this is quite a task and one must find where evidence is similar.

As for the PoW she suffered three underwater hits, two at the stern, one 15 inch amidships, the two stern ones partially exploded, the one amidships was removed at Rosyth and on examination was found to have its fuse fully burned out but it had not ignited the main charge.

It is estimated that it dropped about 80ft short of the ship and travelled without pitch or yaw underwater but slightly rising, it hit the hull and penetrated the ships side, it continued into the outer air space, passed through the bulkhead into the oil fuel space and on through the bulkhead to the inner air space, the shell struck the one and a quarter inch thick torpedo bulkhead, gouged out a scoop, and was deflected back into the inner air space landing on the bottom its nose facing forward.

The diesel generator room on the other side of the torpedo bulkhead began to take on water as rivets had sprung due to the shell force. Although the shell is stated as having low velocity at this point.

Hope this helps
Best wishes
Cag.

A relatively newer book (2012) is "The Battle of the Denmark Strait" by R.T. Winklareth makes considerable effort to assemble time lines of the events form all combatants. By his calculation and included illustration the 5th salvo from Bismarck arrived at 0600 while Hood was in a turn to the port. As such this would tend to burry more of the 12" armored belt under water, temporally reducing the armored freeboard and also presenting the deck armor at an increase angle towards normal (90 deg) which reduces the effectiveness of the deck armor. Holland was trying to reduce the Hood's vulnerability to plunging fire by reducing the range, but the turn briefly altered the geometry.

So many factors come together at one point in time, which leads to continued fascination with these events. Bismarck was both lucky and finally unlucky. A true Shakespearian sea tale.

Bismarks's max. firing range was some 36km with the main gun elevation 30°.
Range when Hood received the fatal hit was 13-16km (depends on sources).
It means Bismarck fired at only some 40% of his max firing range.
May be silly question - Did they keep the same number of the powder bags and elevation was decreased to some 11° (hit was under a pretty shallow angle, e.g. effective against side armor) or did they reduce number of the powder bags to maintain gun elevation up to 30° even for short ranges (hit was under significantly bigger angle, e.g. effective against deck armor)?

Hi All,

Hi 66misos, I'm by no means an expert but looking at the gun tables for Prince of Wales each range distance has a required gun elevation and a resultant angle of fall plus a distance at which max height of projectile is reached.

There are many calculations in gunnery, internal, ie variances and forces to be taken into consideration whilst the shell is in the barrel, and external, ie forces acting upon the shell once the it leaves the muzzle. So adding in a powder amount calculation for each turret (as dependant on courses and angles of target relative to your own ship, this may mean A turret is firing at a different range than Y turret) would be just more variables thrown into the mix.

I guess if a calculation for a angle of elevation has been done in gun tests for each range to create the tables then it allows the gun team to have at least some calculable constants, ie full charge powder gives a certain muzzle velocity, which, after measurements of magazine and gun temperature, barrel wear etc etc are taken into account, gives a range at such and such angle, is a more simple way than having to also calculate how much powder to use for a given range.

As far as I can remember Bismarck used a bagged charge and a cased charge, the case being ejected after firing.

Hope that helps 66misos, sorry if its a bit off topic for everyone else but it was a good question!
Best wishes
Cag.

Normal dispersion of fall at this battle range might be 200 yards or so, Most fire control installations of the era would use parallax corrections, but for surface fire only very minor corrections for the height of the director need be taken into account, along with horizontal parallax. AA solutions were much more concerned with parallax vrs range between directors and mounts due to the size of the target and greater proportional displacement. The only time that I know that charges were adjusted was for shore bombardment where (1) greater angle of fall was better (2) barrel wear is greatly improved by reduced charges. For surface battle full charges were the norm for maximum penetration. The range difference between turrets is well within the dispersion of fall. Some dispersion in range actually improves the chances of a hit given the errors in range finding and the lag period between firing and impact.

USN used a "Stable Element" which gyro stabilized the gun direction automatically with ships roll and course changes. Foreign powers used various portions of these systems, though often with needle matching in the mounts from the directors. Introducing some further lag and error.

Both POW and Hood were unable to use their long base rangefinders on the forward turrets because of spray in the seaway. Hood had a 30' rangefinder aloft, POW only a 15'. However POW, for a new and untried ship did well making three hits, which in the final event led Bismarck into a box from which she did not escape. The hit on her secondary director however took her secondary batteries out of the action early on.

Prinz E achieved a number of hits probably on Hood and certainly on POW. The two hits right at the W/L aft caused minor flooding and wrecked some cabins.

Hi Gents,

thanks for explanation.

66misos

Hi folks.. probably one of my last questions:

I am somewhat confused as to whether the railings atop the rear spotting top roof (shown in attached c1940 photograph which was obviously taken prior to the Type 284 gunnery radar being fitted) would still have been carried after the 284 arrays were fitted? My concern is that the lower planar array (the emitter?) might have interfered with the railings in rotation - although it is obviously narrower than the upper (receiver?) planar array. I am wondering if this was deliberate or just coincidence. I suppose the forward upper rails might have been cut down - similar to how they seem to have been around the forward Vickers .50 positions i.e.: 'Pip' & 'Squeak' by 1940.. there obviously was still a requirement for crew egress up there - noting the ladder fitted on the port side of the control hood..

John Roberts' AOTS outboard profile indicates they were still carried in 1941; however Maurice Northcott's Man O'War publication doesn't show them (I do realise they may have been omitted for clarity - it is otherwise fairly cluttered up there).

If only those April 1941 photos of HOOD actually showed the foretop more clearly.. there is also what looks like a closer version on the HMSHA website but unfortunately has some text over what I am trying to look at.. perhaps what would have been under the text wouldn't have been clear enough anyway.

Could anybody possibly comment ? has any other information come to light? Are there any further plan sets or profiles which agree or disagree?

Thanks in advance for any insight.

Best,

Joseph

_________________
IG: @somewhere_east_of_suez
www.JosephReindler.com

The 1941 spotting top is not well photographed; for instance, we do not know exactly what the new yardarm looked like and how it was fixed to the spotting top. However, the railing was originally only placed around the base of the rangefinder and not extending much further 'upstream' towards the anomemeter.



This image taken before the radar was fitted shows the railing outline faintly.



Here the railing outline is not visible. The lower aerial of the type 284 would certainly interfere with the railing. There was a small path added to the port side of the spotting top and a ladder to reach the fwd spotting top roof after the type 284 was fitted (Image Hood association) suggestion that getting there via the roof of the spotting top was no longer an option.

EJF,

Are you sure that the "path" shown in the top image of spottopa jpg.[32.69] (coloured on the lower) and on the [u]Starboard[u] side, is not a workman's temporary wooden staging with an access ladder? I'm not.

Hi EJ,

Thank you again I really appreciate your reply. I was familiar with that coloured shot from the HMSHA website but hadn't myself thought to try and find an older photo of a similar angle to compare stanchion heights and locations. I agree that if anything was still there then it probably would have been visible from this perspective - even if still there but cut down in height.

By the way I will assume you meant Starboard and not "Port".. some days I really worry myself what I might have said 'pre-coffee'

Thank you kindly again for all of your very helpful replies.

Hi Guest,

Concerning the small accessway I have always wondered the same thing; having seen similar platforms lifted aloft when painting ship etc. Something about it just seems a little hotchpotch to me. Short of another visit to the wreck - or new photographic reference coming to light - I doubt we will ever know the answer to this. At any rate I am painting the ship from ahead of her Port beam so.. problem solved.

Best regards,

Joseph

_________________
IG: @somewhere_east_of_suez
www.JosephReindler.com

Might be a temporary scaffold, though it's also visible later when the King visits Hood



Here it seems railing is still present...?