Subject SMML12/12/98VOL392 Date: Sat, 12 Dec 1998 20:46:19 shipmodels@tac.com.au -------------------------------------------------------------------------------- MODELLERS INDEX 1: Re: Graf Spee 2: Books and kits for sale 3: Re: CV Deck Markings 4: Re: National SMML Model Build 5: Re: Inclining 6: Re: Inclining 7: Re: No Time for Models 8: Re: Carrier Deck markings 9: DECK LETTERS [again] 10: CV Deck Letters 11: USS Thresher/Sturgeon sail query 12: Re: CV Arresting Gear 13: That FLETCHER Idea -------------------------------------------------------------------------------- MODELLERS -------------------------------------------------------------------------------- 1) From: "arthur" Subject: Re: Graf Spee As an aside on the fate of the Graf Spee, it is not generally known that the Brits bought the wreck 3 days after she was scuttled for $16,000 pounds.Then proceeded to take a month to accurately copy and finally remove her gunnery direction system, bit by bit, whilst the German crew looked on and wondered at what the crazy Poms were doing. The system was far in advance of anything the Allies had at the time. I can go along with the statement that she is 50' under. Diving on the Herzogin Cecilie some 30 years ago, (she ran aground on the coast of SW England pre-war) she has also settled 50' down and a mile off-shore, with very little showing above the sea bed. Arthur -------------------------------------------------------------------------------- 2) From: "RLOCKIE" Subject: Books and kits for sale The list is an excellent medium for acquiring and disposing of excess loft insulation to other enthusiasts' lofts but it sees to me that it might be helpful if those offering such goodies indicated their approximate geographical location. It can be frustrating to see a book advertised only to find that the owner lives on the other side of the world and the costs of currency conversion make a purchase not worthwhile. I am not thinking of giving addresses but a country might be helpful to reduce the number of enquiries that ultimately prove to be non-starters. I imagine that one day the problem will be overcome via the web but it seems strange that so far as I am aware, it is not yet possible to send small amounts of capital overseas without extortionate banking charges (at least from the UK). Robert Lockie UK Note from Shane: Sounds like a good idea. Any takers? -------------------------------------------------------------------------------- 3) From: "Michael C. Smith" Subject: Re: CV Deck Markings Paul wrote: >> By the late 1930's, it became apparent that bow landings were not practicable, and the forward arresting gear was removed. << Paul, Your explanation for the letters is perfect - thanks very much. Just one correction - the Navy still liked the idea of landing over the bow, and required the new Essex class ships to be able to do so, so the Hornet should have had bow arrestor gear, as did the first several Essex class ships. It was a damage control measure and a convenience being able to spot planes on the deck aft for a future launch and still land over the bow. It was obviously discarded early in the war, but the outdated requirement remained, at least partway through 1943 - I'm not sure after that. In addition, Lexington had bow gear I believe, as I remember Lundstrom's "The First Team" mentions her landing a few planes over the bow around Hawaii immediately after Pearl Harbor to avoid having to respot the flight deck, which was full of planes aft. I guess she had the gear added in 36-37 when her bow was widened, as you said. Once again, thanks for explaining why the letters were the way they were. Michael Smith Marshall, Texas -------------------------------------------------------------------------------- 4) From: John Snyder Subject: Re: National SMML Model Build Mike Davis' rationale for building a single class--FLETCHERs--was to force the type of split so often seen in aircraft and armor, where apples go up against apples (i.e., 1/48 P-51s against 1/48 P-51s, 1/35 Shermans against 1/35 Shermans), and to begin to establish more of an eyecatching presence of ships and shipmodelers than has been the case heretofore. John Snyder -------------------------------------------------------------------------------- 5) From: "Foeth" Subject: Re: Inclining >> Yeah it was kinda confusing. I hope this helps or confirms your guesses, and I'll >post it for others asking themselves the same questions... << I agree. I was throwing with terms without explaining them. Perhaps it would be a good idea for some SMML's with some shipbuilding experience (I have only theoretical knowledge BTW) to write an article on general ship terms, as many terms are used in literature, unknown to most modelers. NATURAL ROLLING FREQUENCY The *natural* rolling frequency is the time the boat needs to make a complete roll, from center to starboard, to port and back to centre (Doesn't matter which side is rolls to, or which point you take as zero. From starboard to port and back will also qualify), in undisturbed water, after you gave it a little push. As said, a ship can founder when it is hit by waves in exactly this frequency. In this case, the ship will start a resonating movement, meaning that motions will not damp out, and could get worse. Even the slightest waves can have result in violent motion. This frequency is generally called the Eigenfrequency, and every object has one, or more. Just like a weight at the end of a rope will always have the same frequency (Swinning left to right), no matter how far you put it out of it's original position). These frequency's are generally to be avoided, but sometimes, you can't help it. Notice you car vibrate when you are waiting for a traffic light; the car is resonating. Physically speaking, the eigenfrequency is the frequency which takes the least energy of all modes of motion. This means that you need little force for big effects. PORPOISING This is one of these rare situations were waves hitting the ship will result in violent motions, and the ship will have an excessivepitching motion. There is a picture of a North Carolina class BB porpoising in Garzke&Dulins book. SPRINGING In this case, not the ship as a whole will resonate (as in motion), but the hull itself: due to waves, the hull is excitated in it's natural frequecy, and will deform more easily. FASTLY DECREASING POLAR INERTIAL MOMENT OF THE WATER AREA All right. I didn't even use these terms in this order myself before, and it sounds ridiculous. Sounds more like Star Trek! It's a row of academic terms. But: Sketch a ship (just sketch a box) (looking at it from behind, or from afront) in it's horizontal position, with a waterline also horizontal. Now, draw a ship heeling to one side. The waterline is now not horizontal in respect to that ship. Draw that non-horizontal line in the first drawing. If you concider this situation, you can see that those two lines make up two triangles, if you take the ship's side as the triangle's third leg. If you concider the shape of the vessel underwater, a single thing has happened: One of these triangles of the underwaterform has moved to the other side of the ship. (Think of it as sawing a piece of your hull form, and glueing it on the other side). The centre of bouyancy has moved with the triangle. The mass of that triangle is about half the width of the ship, multiplied by that lenght of the sidehull between the waterlines (Which is 1/2B*tan PHI, if PHI is the rollangle) multiplied by 1/2 (As it is a triangle, the area is L*B/2). This is the amount of water transferred from on to the other side. The distance it has moved is 2/3 B (If you realise a triangles centre of gravity is 1/3 of it's height above base). This results in a moment around the ship center of gravity, being the product of the triangle's mass and that distance. The product of all B's and fractures is the Inertial Moment of the waterplane area. As lenght is expressed in feet, area's in square feet, and volume in cubic feet, the moment of Inertia is expressed in quadruppel feet, making it a weird thing indeed. If you really multiplied all those B's, you'll see an expression with cubic B's, meaning that if the ship is twice as wide, the inertial moment increases by a factor of 8. The whole point of it (There was one), is that the stability of a ship is heavily dependent on this inertial moment, as it the factor that determines where the metacentre is (As explained more understandable by Fritz Koopman). What happens if a ship rolls, and a deck hit's the water? Well, that trick with the triangles doesn't work any more. The waterarea is now much smaller. As the inertial moment decreases cubically with B, a deck hitting the water will make the metacentre plummet down. This is why freeboard is important to ships, as the point of vanishing stability is now larger, than without freeboard. I don't kown if I used the term Polar correctly, I never knew what that meant (Don't feel like looking it up!). CARENE DIAGRAM In this diagram, the ships centre of bouyancy, waterplane area, lines area's etc are expressed against draught of the ship, at a random trimming angle. It shows the various charcteristics of a hull form in a single diagram. How to draw it: Draw a line devided in 20 segments (the usual 20), and as a left axis the forward draught, and on the right the aft draught. Take the middle of the 20 lines (line 10) as a reference axis. Now, for a ship draw a line being a 3 feet even draught (3 ft FWD draught, 3 ft AFD draught). Calculate, for instance, the displacement for three feet, and plot it against the centre axis. If you do this for various draughts and ship charecteristics, you will have a maze of lines, forming the carene diagram. For any trim angle, plot a line from random FWD draught to random AFT draught, and read the results. You can also calcutate the area of all lines at all draughts, forming the bonjean curves. Always boring, Evert-Jan Foeth -------------------------------------------------------------------------------- 6) From: Norman Samish Subject: Re: Inclining Hi Fritz, Thanks for the information. It's very helpful. I heard a tale some time ago about a destroyer in the arctic that encountered a gale so severe that it heeled over until the deck was awash. The captain refused to bring it about and it continued like that for some time. I found that difficult to believe. Do you think it should have capsized? (I suspect the story might have been a tad exaggerated.) >> Norman, Yeah it was kinda confusing. I hope this helps or confirms your guesses, and I'll post it for others asking themselves the same questions... longitudinal righting arm, metacentric height, rolling period, natural rolling frequency, natural pitching frequency, fastly decreasing polar inertial moment of the water area, Carene diagram. << -------------------------------------------------------------------------------- 7) From: "mike.leonard" Subject: Re: No Time for Models Michael Smith ventured: >> I love this list - I'm having so much fun! I just wish I had time to actually build >anything. << In your (our) dreams. Oh, if only we didn't have those pesky jobs and families… Mike L -------------------------------------------------------------------------------- 8) From: b29@ix.netcom.com Subject: Re: Carrier Deck markings John Snyder has it right on the color. Mahogany is reddish-brown and that's exactly right. "Maroon" is really a purple-brown. However, the letters were only on the "round-down" or ramp of SARA and LEX for a relatively short time. They were moved on to the flight deck just forward of the round down early on and remained on the flat part of the deck until no longer used. I have also located a photo of HORNET in late Oct. 1941, in which it appears that the letters HNT are on the deck at the bow. It is difficult however to tell for sure, because the angle of the photo is only slightly above flight deck level. Paul -------------------------------------------------------------------------------- 9) From: PulligS@aol.com Subject: DECK LETTERS [again] On page 8 of Fahey's TWO OCEAN FLEET EDITION is a photo of YORKTOWN with a " Y " on her inside funnel. I had seen this before but forgot. Wonder if she carried it outboard? Sam Pullig -------------------------------------------------------------------------------- 10) From: PulligS@aol.com Subject: CV Deck Letters Went back and reviewed my books on carriers. It looks like the carriers got the deck letters previously IDed in about 1930, about the same time as SAROTAGA got her black stripe. By 32 both big carriers had their letters. LANGLEY did not and I do not believe she ever did. YORKTOWN and ENTERPRISE had them both fore and aft. Preston says because they could land planes both ends. SAR and LEX only had then aft. RANGER had them aft across the elevator one letter each 2 on elevator. No letters forward. No photo of WASP deck but Freidmans plan shows it. Contrary my first post and contrary to Fahey I do not believe that HORNET carried letters. Reason 1 by Oct 41 LEXINGTON did not have hers anymore and had been repainted a darker color. Reason 2 HORNET was commissioned in this darker paint color, therefore you could assume she didn't have letters either. That's my logic from looking at one set of photos but Fahey says specifically in his WAR EDITION page 8 that she carried letters fore and aft and the paint color looks light. Does anyone have a photo of her as built showing the deck? That's enough for now. Sam Pullig -------------------------------------------------------------------------------- 11) From: "mike thrupp" Subject: USS Thresher/Sturgeon sail query Does anyone know the length,width, and height of the sail on the USS THRESHER/STURGEON class SSN's? I have plans but have some doubt as to their accuracy. Thanks Mike Thrupp, Birmingham, England -------------------------------------------------------------------------------- 12) From: ECammeron@aol.com Subject: Re: CV Arresting Gear I don't think the forward arresting gear was removed from Enterprise and Yorktown in the late 1930's. The Essex Class CVs, CV-9, 10, 11, 12, 13, 16, 17, and 18, were built with arresting gear forward. It wasn't removed til their overhauls in 1944-45. Hornet and Wasp still had their forward arresting gear in 1945, also only single flight deck catapults. Eugene Cammeron -------------------------------------------------------------------------------- 13) From: John Snyder Subject: That FLETCHER Idea OK, so far there's been no negative response to Mike Davis' idea for a bunch of 1/700 FLETCHERs for Orlando. So... Time to get underway (so to speak). Any 1/700 FLETCHER kit (Skywave, Matchbox, Tamiya, resin), any variant, any time period from WW2 to 'Nam. Build one, build two, build a bunch. Build out-of-the-box, or go to the Nth degree of superdetailing. Let's keep in touch via SMML and let each other know how we're doing collectively. This should open a few aircraft/armor eyes. And start thinking beyond--ESSEXs, recreating "Murderers' Row...? John Snyder Snyder & Short Enterprises The Paint Guys -------------------------------------------------------------------------------- 14) From: "Jeffrey Roberts" Subject: RE: Dutch Destroyers I'd like to say thanks to Harry Dente, Art Nicholson, Evert-Jan Foeth (who e-mailed me off list) and Shane for their help and suggestions regarding my quest for source material on the Dutch Callenburgh class destroyers Isaac Sweers and ZH1 (ex-Gerard Callenburgh) -- this is a modeling project I've wanted to undertake for some time now and in view of the scarcity of (especially English language) sources on this subject I need all the help I can get! Thanks too to Greg and Shane for making it all possible via SMML. I have got most of the items suggested thus far (Lenton's pocket book on the Dutch Navy, Conway's, and especially WI No 1 for 1988. The article on the Dutch building program of 1939 is really excellent and includes some fine photos though no plans---in fact WI has included a fair number of good articles on the Dutch Navy over the years) but I've received several good suggestions for other places to check for more information. Art, if at all possible, could you have the photos of the Isaac Sweers that you mentioned posted to the SMML picture page? I've not seen the photos of her in the series you mentioned. Thanks again to all and happy holidays. Jeff Roberts North Hollywood California -------------------------------------------------------------------------------- End of Volume