Subject: SMML VOL 2991 Date: Fri, 11 Nov 2005 21:46:13 +1100 The Ship Modelling Mailing List (SMML) is proudly sponsored by SANDLE http//sandlehobbies.com For infomation on how to Post to SMML and Unsubscribe from SMML http//smmlonline.com/aboutsmml/rules.html ---------------------------------------------------------------------------- MODELLERS INDEX 1 Re Repulse Radar 2 Scale Model Ship Propellers 3 Re Federal Navy Frigates 4 Re HMS Repulse RDF 5 Re Repulse RDF 6 Re HMS Repulse RDF 7 Re Frigates & square rigged warships 8 Re Federal Navy Frigates, and their masts 9 Re MAC Ships 10 Hull plating of HMS Rodney / Nelson 11 Re U-boat questions 12 Re Federal Navy Frigates 13 Re Hasegawa Vanguard 14 Airship Carriers ---------------------------------------------------------------------------- MODELLERS ---------------------------------------------------------------------------- 1) From WRPRESSINC@aol.com Subject Re Repulse Radar Type 286p used the smaller rotating aerial which also used by type 291. ---------------------------------------------------------------------------- 2) From "bill hicklen" Subject Scale Model Ship Propellers Dear Sir, I am looking for 3/4 inch and 1/2 inch ship propellers. Material make is not important. Anyone have any references?? Many thanks. Bill Hicklen Petoskey, MI, USA ---------------------------------------------------------------------------- 3) From LymanJohnF@aol.com Subject Re Federal Navy Frigates After realizing the question was not about the West German Navy . . . My comprehension of the various factors that entered into square-rigged ship design and layout is limited, but I believe that mast spacing had nothing to do with boat stowage or other secondary considerations and everything to do with sail area, wind pressure, and the transmission of wind pressure to the hull to effect movement. From over forty-five years of reading and research in the general field, my recollection is that unevenly-spaced masts would be the rule, rather than the exception. For square-rig design factors generally, and USN frigates particularly, track down Chappelle's History of the American Sailing Navy. It will tell you more than you ever wanted to know. John F. Lyman ---------------------------------------------------------------------------- 4) From "Harold Stockton" Subject Re HMS Repulse RDF Concerning the Type 79 and 279 series of radars http//www.vectorsite.net/ttwiz1.html , "A prototype version of the Type 79 radar was successfully demonstrated in early 1938. By the end of the year, the Type 79 had been installed on the battleship HMS RODNEY and the cruiser HMS SHEFFIELD. It would be soon fielded on other vessels and be upgraded to the improved 'Type 279'. "The Type 79 and Type 279 were similar, both using separate transmitting and receiving antennas mounted on their own masts but rotating in synchronization. The antennas were small, resulting in a wide beam, which was adequate for detecting aerial intruders at ranges of up to about 80 kilometers (50 miles), but not so good at targeting naval vessels. It was also not very good at picking up low-flying aircraft." This is the reason for the single antenna in the 279M. "The need for more precise targeting led Royal Navy researchers to hastily develop a 1.5 meter / 200 MHz radar, the 'Type 286', based on the technology Bowen had developed during his AI work. The initial 'Type 286M' used a fixed antenna, meaning the ship had to change direction to point the radar beam. The Type 286M could pick up a surfaced submarine at a distance of no more than a kilometer if the vessel carrying the radar was pointed in the right direction. "In March 1941, a Royal Navy destroyer managed to spot a German submarine at night using the Type 286M and then rammed the submarine, sending it to the bottom. However, that was basically nothing more than a stroke of luck. A 'Type 286P' with a steerable antenna would be introduced in mid-1941. "The Royal Navy was working on a better solution even as the Type 286 was going into service, in the form of a 50 cm / 600 MHz radar for naval gunfire direction. A prototype set was available by the end of 1938, and put through successful sea trials in mid-1939. Designs for a production set for surface fire control, the 'Type 284', and for anti-aircraft fire control, the 'Type 285', were in place in 1940 and were being delivered to the Royal Navy in 1941. "Both the Type 284 and Type 285 used "Yagi" antennas, essentially a row of dipoles of increasing size mounted on a rod, with the beam generated along the axis of the rod. A modern household broadcast TV antenna is a common example of a type of Yagi antenna. The antennas, which workers also called 'fishbones' for their appearance, were arranged at slightly different angles away from the centerline of the radar, with each side driven in an alternating fashion. The returns to each side would be different until the target was on the centerline. This technique, known as 'lobe switching', could provide very precise azimuth angles. "Both the Type 284 and Type 285 had horizontal lobe-switching. It is unclear if the Type 285 had vertical lobe-switching, which would have been handy for an air-defense radar." About the Type 286 Warning Radar you mentioned for Repulse, it was of the "Fixed antenna with beam switching" type that was improved in the Type 290 and was generally started to be installed in the 1941 period. According to http//hmshood.com/ship/specifications/maingun.html , "In 1941, this was further augmented by the incorporation of a Type 284 gunnery radar (range @10 nm/18.5 km). The Spotting Top 15 ft/4.6 m rangefinder was removed when the radar was added. Additionally, a Type 279M radar was fitted that could also provide surface ranging if necessary (range @ 9nm/16.6 km). Inputs from these devices could be fed into Mk V Dreyer fire control tables in the 15" transmitting stations for coordinated fire control." With the Type 279M radar for Repulse, according to http//www.hmshood.com/ship/specifications/radar.html , "The Types 279 and 279M were largely the same with the most noticeable difference being that the standard Type 279 required 2 antennae (one to transmit and one to receive), whereas the Type 279M required only one antenna. This was located high above her main mast. The source confirming the installation and testing of the Type 279M is Admiralty document ADM 220/76, "Reports of performance in HMS Hood and other vessels of Type 279M radar". This document is housed at The National Archives, Kew." Following your points of ". . . in addition to 284," The Type 284 was a 50 cm / 600 MHz shipboard gunnery radar, with Yagi antennas and horizontal lobe-switching. "Type 286 Warning Radar set in September 1941 en route from Scapa Flow to Freetown." The Type 286 was a .5 meter / 200 MHz shipboard radar, derived from early AI work. The early Type 286M had a fixed antenna, while the improved Type 286P had a steerable antenna. "I'm unfamiliar with the 'M' variant of Type 279; the basic Type 279 is usually quoted as a long-range air warning set (albeit with some surface warning capability), rather than a close range AAA control for added gunnery ranging capabilities as you describe 279M." The Type 279 series was a 7.5 meter / 40 MHz shipboard air-warning radar, featuring twin antennas on separate masts, rotating in synchronization, which was a development of the Type 79 series. ". . . that 279, 281, 282, 284 and 285 were fitted during the August - November 1941 refit." We have already looked at the 79/279, 282 (onboard the POW), 284, and 286 series of radars, but I am unclear what the 285 radar have to do with this discussion because it was a development of the Type 284 adapted for small ships. But, then there was the 271, 273 and 277 "cheese" radars. Interestingly, a discussion about these two ship's HACS-controlled guns can be found at http//www.navweaps.com/index_tech/tech-066.htm, "For example, during the destruction of Force Z, both HMS Prince of Wales and HMS Repulse apparently failed to shoot down a single plane with their HACS-controlled guns. Interestingly, the first attack was by eight high-level bombers, the very threat that HACS had been designed for. Partly due to poor fleet handling by Adm. Phillips, it took a long time for the British ships to get the range on the Japanese aircraft, allowing the Japanese pilots to conduct their approach practically unopposed. "During this particular attack, a total of 108 rounds were fired by the 5.25-inch guns on HMS Prince of Wales and a further thirty-six rounds were fired by the 4-inch guns on HMS Repulse. Five aircraft were damaged, two seriously enough that they were forced to return to base without dropping their second bomb. In return, the Japanese were able to score one hit on HMS Repulse with a 250 kg. HE bomb. Of the three Japanese torpedo bombers that were actually shot down during the rest of the battle, one was most likely hit by HMS Prince of Wales' 2 cm Oerlikons and the other two were downed by HMS Repulse's 2-pdr. pom-poms. However, all three planes had already launched their torpedoes at the ships." As the above quote states ". . . one was most likely hit by HMS Prince of Wales' 2 cm Oerlikons and the other two were downed by HMS Repulse's 2-pdr. pom-poms." And we must then ask why such a poor showing in either of these ship's close-in AAA performance? These units did fairly well until loss of power and excessive list prevented further use in the later parts of the action. The Bofors were praised and recommended over the Pom-Poms. When we read on http//www.microworks.net/pacific/personal/pow_repulse.htm , that ". . . the Prince of Wales being incapable of operating at full capacity because one of her boilers was undergoing repairs. Though of far more concern was the condition of her ultra modern surface scanning Radar, which this was inoperative. On the afternoon of December 8, Squadron Leader TC Carter was sent aboard with two RAF technicians to ascertain if the situation could be quickly remedied; he stated "I was somewhat irritated when I found that the set had been unserviceable throughout the week that Prince of Wales had been in Singapore, and it was only now when she was obviously being prepared for sailing that we were called in and asked to do the job at once. In the event we could not. Had we had been called in a couple of days earlier we might have been able to do the job. So it was Prince of Wales sailed with that radar set unserviceable." But we find further information on http//www.navweaps.com/index_inro/INRO_Repulse.htm , that the destroyer Tenedos radioed that she was being bombed and pre-warned Force Z. ". . . the signal was received from Tenedos. We were doing 26½ knots at the time and still working up. The signal about aircraft being in the vicinity was soon confirmed by P.o.W. with R.D.F. [Radio Direction Finder, or Radar-Ed.] so the first degree of AA [anti-aircraft-Ed.] readiness was assumed." This is confirmed in Middlebrook and Mahoney's book BATTLESHIP on page 137 where it states "Twenty-five minutes after the (Japanese reconnaissance) plane had been sighted the echoes of a formation of aircraft were picked up by radar. A general order was issued at once by the flagship (POW) 'ASSUME FIRST DEGREE ANTI-AIRCRAFT READINESS'." Ending, I am unsure what weapon was atop the starfish, but it would probably be a single 2-pdr. pom-pom, unless you know of "fifties" being installed. [I answer this question in my next responce.] Harold ---------------------------------------------------------------------------- 5) From "Harold Stockton" Subject Re Repulse RDF Art Nicholson wrote >> I'm a bit puzzled by Mr. Stockton's post on this subject in SMML 2988. Yes, the Repulse did have a Type 284 gunnery radar, but the question I was responding to seemed to be directed at her air search radar. If you are suggesting the Repulse did not carry an air search radar, I would rely upon Mr. Armstrong, the ship's radar officer, who told me she had a Type 286P radar fitted on her foretop in September 1941 and indicated its position on a plan I sent him. (He said the Repulse also had a Type 273 surface search radar still in crates, but the question I was answering didn't seem to be directed to that one either.) I think Mr. Armstrong would've mentioned a Type 279 radar if the Repulse had had one. << And Mr. Tim Stoneman wrote to me about the following on this same subject which we have corresponded offline. I will forward that posting to you all for your examination. Harold Stockton ---------------------------------------------------------------------------- 6) From "Harold Stockton" Subject Re HMS Repulse RDF Tim, You wrote "Finally, I've been unable to locate any other reference to, or photos of, the AA weapon atop REPULSE's mainmast starfish - can you suggest where I might look please?" I misspoke about the top-side AAA mount being a single Pom-Pom. From this link http//www.navweaps.com/index_inro/INRO_Repulse.htm , it is stated "Next I saw a large number of splashes as [would be made by] . . . 0.5 in, stretching from about 50 yards from the starboard side to about 600 yards on a bearing of 100 degrees. I looked up at the 0.5" gun on the after superstructure, fully prepared to give him a dressing down, as there were no aircraft even in line with the splashes, but saw that the gun was trained for a forward bearing." So, there was at least one quad 0.5" weapon on Repulse, but the link above lists the effective performances of six (6) and the four (4) 0.5" weapon positions. All the photographs of ENSIGN 8, from the cover to pages 36 and 38 it clearly shows the location of one of these quad 0.5" weapons on the starfish platform, and is especially clear on the bottom of page 35 where the caption states "Repulse in 1939. Note the quad .5-inch machine guns on the mainmast platform. Though, where all of the "Ready Use Rounds" would have been stored I do not see. This same photograph as just mentioned, and the ones on preceding page, clearly shows the Type 284 mounted atop the HCAS directors. In the book BATTLESHIP it was related that a general order had been given to conserve ammunition before any contact had been made, but that the first attack inspired quite a few in the AAA departments to believe that this was not any way to defend their ship effectively. As such during the lull between the first and second attacks, much effort was made to replenish as much ammunition forward to the various AAA weapons as possible, and all of this had to be done manually. Concerning exactly where the six (6) 20mm cannons that were on board Repulse at this date is unclear, but the above link says "I ran aft to No.5 Oerlikon with Mr. Williams, Bos'n, and told the Marines on No.3 triple gun to slip the two Carley floats on their deck." From the book BATTLESHIP, page 155 says "Our Oerlikon guns were going right through their fuselages." And on page 182 during the second attack "Lieutenant Pool was a fire distribution officer at one of REPULSE's pom-poms, a lethal weapon at short range 'It became obvious that the Japanese aircraft were firing their torpedoes out of our effective pom-pom range [including the Oerlikons and quad 0.5" weapons on Repulse.]. Almost immediately, another attack developed . . . As the ship's position appeared helpless. I did not shift target after these aircraft had dropped their torpedoes. As the two aircraft passed by the ship we hit and set on fire both of them and they crashed.' " The two Bettys were piloted by Petty Officers Satoshi Momoi and Ryochi Yaue. The above link confirms these comments from the book when it states "I know that No.5 Oerlikon was firing for quite a time after we had commenced abandoning ship, because we had difficulty in keeping men clear of the muzzle. "M.1 Pom Pom Reported by Lt. Pool and CPO Thacker, G.M. Several guns kept out of action through the connecting link becoming disconnected and the gun expending its belt. Several stoppages were caused through extractors not rising, probably due to thick bases on damaged cylinders. At commencement of last attack only one gun was firing, and this eventually stopped through extractors not rising. "M.2 Pom Pom Similar report to that received from M.1 but less reliable source. "M.3 Pom Pom Power elevating and training failed when first bomb struck. Captain of the gun, PO Bray, ordered "Hand elevating and training," and the changeover was satisfactorily carried out. After about 10 minutes power was again tried, found to be correct, so changed back. When the first torpedo struck, power again failed. Tried to change over to hand, and although training changed over correctly, elevation would not. The elevating handwheel was free but the clutch could not be put over. Training was very stiff when the ship developed a list. Stoppages At the end of the first torpedo attack only one gun was firing. Five had separated rounds, one had a round which could not be withdrawn from the belt, and in one the extractors would not rise. Mr. Ward, Commissioned O.O. [Warrant Ordnance Officer-Ed.], and O.A. Jeffries [Ordnance Artificer-Ed.] worked on the guns during the lulls and eventually got three into action again. The ammunition supply was good, and if all the guns had been firing I think the supply would have coped with the expenditure. "Nos.1 and 2 Oerlikons No reliable report available. "No.3 Oerlikon Fired 4 magazines without a stoppage. The fifth magazine, which was filled during the action, fired about two-thirds of a magazine when it had a stoppage. PO Devis, G.M., filled the magazine and checked that the tension on the spring was 60 lbs. After about 40 rounds the tension was not sufficient to force the round down, and the moving mass on going forward tore the lower half of the cylinder out and sprayed neonite over the breech. Time did not permit the gun being again brought into action. "No.4 Oerlikon No reliable report available. "Nos.5 and 6 Oerlikons Fired satisfactorily. Ammunition supply was adequate. "Nos.1 and 2 0.5 in No reliable report available. "Nos.3 and 4 0.5 in Satisfactory. Ammunition adequate." It does become quite clear that both ships were doomed; not by a lack of aerial warning radar, inadequate HA capabilities of REPULSE's 4" mounts or POW's faulty HCAS directors, but rather to a large "blind-spot" between the effective ranges of their secondary weapons and the effective range of their inadequate numbers of close-in AAA weapons and a lack of aerial cover. But, then the same thing happened off of Iwo Jima and Okinawa with the American fleets, and they had plenty of close-range and directed AAA weapons and adequate aerial cover. Harold From "Tim Stoneman" Subject Re HMS Repulse RDF >> Harold, Thanks for your comprehensive reply. I've one or two observations, and a question. Accepting that the description was Greg Goebel's website, I'm not sure that the normal Type 284 aerial was what I understand as a Yagi - it consisted of a row of dipoles in a trough or troughs across the front of the director, although it had very similar electronic components to the Yagi-fitted Type 285. Your 8th paragraph speaks of a fixed antenna for Type 286 on REPULSE - Ken Armstrong's correspondence with Art Nicholson indicated that it was Type 286P with a steerable antenna. I mentioned Type 285 in my remarks about RENOWN merely to complete the list of her RDF sets - although you say 'it was a development of the Type 284 adapted for small ships', its primary function was for high-angle fire control, and was fitted on HA.DCTs in large ships as well as on directors of smaller ones - although some larger ships carried the yagi aerial usually fitted with Type 285 for controlling surface fire (eg SUFFOLK, KGV (aft LA.DCT)) - probably with 284 electronics. Finally, I've been unable to locate any other reference to, or photos of, the AA weapon atop REPULSE's mainmast starfish - can you suggest where I might look please? Thanks again, Tim Stoneman << ---------------------------------------------------------------------------- 7) From Raven0222@aol.com Subject Re Frigates & square rigged warships I read the posting on the debate over the placement of the masts with regard to ships boats. I think that with regard to this type of vessel we tend to sometimes forget the forest for the trees as it were. The scenario is probably correct that the masting was changed from the plans to the actual ship because of availability of ships boats and their subsequent sizes. Rigging and placement of such boats aboard changed as often as the weather. Literally. The process of warships has not really changed. Each ship then as now had a huge complement of support personnel for each voyage. Not just the crew and captain but several meteorologists, cartographers, cargo masters and sail experts. Each voyage was fully researched for winds, storms, weight and distribution of cargo (including ships boats). Sometimes more crew meant more boats. Smooth seas and you can move the boats outboard, rough conditions and those same boats could swing inward and be lowered to chocks, then secured. But, very much in the way. Rigging a ship to her plans may be accurate for the plans, however, for real life, imagine a scenario....... and model that. The plans show you where stuff was supposed to be. People like to move stuff around. We recently had cause to build the Balclutha for a client. The ship sits in the Maritime Museum San Francisco. The ship today hardly resembles her plans. She was sold and transformed to do so many things. Then, when she became a museum they really had to change her for the tourist trade. Nothing sharp, stair incline greatly reduced, access hatches cut wider and so on. Fair winds and following seas Christian A. Raven Raven Arts RavenArts.com ---------------------------------------------------------------------------- 8) From Fritz Koopman Subject Re Federal Navy Frigates, and their masts Hi Franklyn It's all in the sail handling. The distances between the Fore and Main has to do with TACKING, and Main to Mizzen has to do with TRACKING. During a tacking maneuver, the main and mizzen sails are hauled hard to the new tack first (in unison) as the vessel passes head to wind, meanwhile the fore's are left on the old tack, to backwind and continue to help force the bow around. The space between the Fore and Mainmasts is dictated by needing clearance between the ends of the main and fore-yards, lest they punch a hole in the others sail, or worse foul together, such that they are locked yard-tip to yard-tip. (This could put a damper on ones day, especially if it happens while trying to maneuver during battle, or close to a lee shore! -o ) You can demonstrate this principle to yourself with a scale model. Rotate one end of the fore yards as far aft as the shrouds will allow, and then rotate the same side of the main yards as far forward as the shrouds allow. If the mast are at the right distance, they shouldn't touch with a couple scale feet between them. Now, as for the mizzen, this requires an understanding of how nasty it can be to steer some of these older ship. Most people have no idea how little that rudder has to do with steering ships of that hull form. In fact the rudders only purpose is to induce a major turn by causing drag on one side, and the accompanying dynamic high pressure to kick things into motion. Once in a hard turn the rudder alone will not stop it, nor re-effect the course of the ship. To stop a hard turn, the Spanker is used. By over sheeting, and controlling the pressure. This is what really stops the turn and steadies the ship, ie the ships rudder is in the air, not the water. Therefor the mizzen will be located such that this sail has the best effect on the ships center of effort (CE), relative to its center of lateral plane (CLP). Ships CE is the center of its sail plan, and CLP is same thing with the underwater profile. The best spot for leverage tends to be about 36% (of the sail area) aft of the CLP. Since the mizzen yards are worked in conjunction with the mains, there is no real minimum distance to push it any farther aft, which would generaly require lengthening the ship at the deck. The second, yet related, reason for the mizzen position is tracking on any point of sail other than a run. In this case the mizzen sails become a giant trim tab. By increasing the area on aft mast, you can force the bow to round up into the wind, and to compensate one would have a weather helm, where you would be constantly trying to turn down. Oppositely, by reducing the sail area the wind pressure is shifted forward, causing the vessel to round down, and inducing leeward helm. By adjusting the mizzen area just right, the helm goes neutral, and the ship begins to TRACK along in a straight line with little to no force on the wheel. The amount of round up or round down, varies with the wind strength as well. So it becomes crucial that the mizzen is placed at a spot where its minimum an maximum sail areas can effectively trim and ballance through the entire range of wind strengths and headings. I hope not to confuse things for anybody, but that's classic rig design 101. Hope it helps. Best Regards Fritz Koopman Salem MA ---------------------------------------------------------------------------- 9) From "Nuno Rubim" Subject Re MAC Ships Thank you to all who answered to this issue. Nuno Rubim ---------------------------------------------------------------------------- 10) From Maarten Schönfeld Subject Hull plating of HMS Rodney / Nelson Hello all, Is anybody on SMML in posession of a hull skin plating diagram of either battleship HMS Rodney or Nelson? Such a diagram is sometimes referred to as a 'Shell Expansion.' I am looking in particular for the area below the waterline, as the upper part is well documented, but the lower is not. Also, photographs of either of these ships in drydock seem to be extremely rare, so if anybody can help me with such pictures I would be very grateful too. Same is true for these ships still on the stocks during construction. Regards and thanks! Maarten Schönfeld Netherlands ---------------------------------------------------------------------------- 11) From Bill Michaels Subject Re U-boat questions Get a copy of "Iron Coffins"-- lots of good info about U-boat operations.... ---------------------------------------------------------------------------- 12) From DILIANE@aol.com Subject Re Federal Navy Frigates Maybe the reason for the uneven spacing of masts on ships like the constitution, has to do with who far the yards swing. Otherwise the sails and yardarms would keep fouling. Jim Campbell Chippewa Falls, Wi ---------------------------------------------------------------------------- 13) From "Raymond Guy" Subject Re Hasegawa Vanguard G,Day fellow Smmlies. The mention of the Vanguard kit in recent postings has triggered the possibility of having a go, so to speak,once more at trying to create a reasonable facsimile of the original out of this abortion of a kit, which has been lying around for years ( after opening the box and examinig the parts I gave up in disgust). R&R Battleships of WW11, aswell as some very good photos of her taken in Capetown Harbour during the Royal visit of 1947,and in addition a souvenir booklet of the ship with a large number of detailed photos is also to hand.The references are there, but has anyone out there built this thing with some modicum of success in turning it into what it is supposed to be. Furthermore the kit desperately could do with some detail that only photoetch components can provide, would the 1\400 photoetch for the KGV provide some components ? Any suggestions ( including consigning the whole shebang to the dustbin ) from the vast pool of knowledge out there would sincerely be appreciated. Ray in Capetown ---------------------------------------------------------------------------- 14) From Subject Airship Carriers Thanks Richard, I did not know of the American version, but I did know of the trials of HMA 23 in 1918 which proved the capability of carrying and operating aircraft on an airship. It was part of a program to try and develop an airborne battleship to duel the Zeppelins in their own element, weapons included a 2 pounder cannon. But the British manufacturers could not match the German experience and engineering, the ships had too little lift and range. The project also suffered from the usual attempt to have cake and eat it, they also fitted them out as bombers, further adding to the weight problems. But had the development continued the skies would be pretty amazing, like something from an Edgar Rice Burroughs novel with airborne fleets cruising into battle. Sadly however I fear son number two gained this knowledge from neither project, but rather from Indiana Jones and the Last Crusade. ---------------------------------------------------------------------------- Check out the SMML site for the List Rules, Reviews, Articles, Backissues, Member's models & Reference Pictures at http//smmlonline.com ---------------------------------------------------------------------------- End of Volume