I highly recommend 1/600 scale for doing ship drawing

I drew my last destroyer drawing at 1/600 scale (50ft/in) and I remembered why I like the scale. That is large enough that drawing accuracy is greatly improved. 1/12oo scale is too small. Small errors have a large effect on the drawing. I have done 770ft battlecruisers at 1/600 scale and it really helps for that size as well. The only problem with it is that scans must be pieced together graphically, and there are always small alignment errors.

I ran my big US destroyer design

I entered the initial values into a spec for my 2400 ton destroyer. I ran the program, and then drew a drawing. I tweaked the values based on my drawing and then reran the program. The normal range is 5110 nm at 15 knots and the maximum range is 10586nm, also at 15 knots. The metacentric height is very acceptable. At normal load, it is 3.3ft and and deep load is 5ft. The normal fuel load is 420 tons with an additional 450 tons at deep load. My design is flush decked with two funnels. There are two twin 5.1in/50 turrets forward and one twin turret aft. There are two quintuple torpedo tube mountings astern, but on top of the superstructure. My stability figures really do not account for those weights, but the stability situation is good enough that it should not be a problem.

Destroyers for War in the Pacific

If a 2100 ton destroyer is good for Pacific War fighting, why not a 2200 ton destroyer? The Gearing class dimensions also seem to be pretty reasonable. I would have thought that I would at least go with a 390ft ship. I would probably use coefficients of Cp=0.66 and Cm=0.82. For my liking, I am seeing 390ft as too long for a ship whose NORMAL displacement is 2200 tons. The draft is too shallow to be reasonable. The problem is that a Standard Displacement is quite different from a normal displacement. The normal displacement needs to be at least 2400 tons. Given that, then the dimensions would be 370ft x 38ft x 11ft. The guns would still be 6-5.1in/50 with 10-21in TT. The speed need only be 34 knots.

Super-Destroyers

Frank Fox told me that he had designed an American-style large destroyer for the WWII period. I have an interest in such a thing, myself. I have thought that a 5.1in gun (13cm) would be the thing to use. The gun is considerably more potent than a 5in/38 or a British 4.7in gun. The 5.1in shell is about the upper limit of what is easily manhandled. The British almost adopted such a gun in the 1930's, and then decided that the shell was too heavy. They stayed with the 4.7in gun until they finally adopted a more modern 4.5in DP gun during WWII. I would want a ship about 2750 tons with 6-5.1in/50 guns, and a torpedo armament of 10-21in TT. We all would wish for a 24in torpedo with capabilities equal to the Long Lance, but no one but the Japanese had done the work required to develop such a weapon. That gave the Japanese destroyers and cruisers a great advantage into 1943, until American night tactics and radar fire control finally gave them an edge.

Cruiser design patterns

I think that high-freeboard, flush-decked cruisers are a good design pattern. I have typically included at least a small transom stern, as well. The bow should have some flare and should be 5-10 ft above the amidships freeboard. The stern should be at least 2-3 ft above the amidships freeboard. I would only follow that pattern for larger cruisers. For smaller cruisers, I would either have a raised forecastle or at least a low stern and a fairly high, flared bow, even if the ship were flush-decked. An example would be the Atlanta class ships. For the larger ships, I would use triple turrets, usually 9 guns in three turrets. For ships with guns smaller than 8in, I would have at least 12, if not 15 guns in triple turrets, similar to the Brooklyn class and the original Mogami class design.

President Roosevelt was interested in having a ship like the French super-destroyers

In 1940, President Roosevelt expressed an interest in having a super-destroyer like those used by the French (such as the Fantasque or Volta). Given how the American designers gold-plated everything, the design turned out over4,000 tons, at which point all interest died. American design standards were quite different from those of the French, and there were some things you just couldn't due (regrettably). President Roosevelt had influence. The only reason that the Iowa class ships were built was due to his interest. The navy establishment had no interest. They wanted to build worse ships. They had no interest in a really fast battleship, despite the fact that they turned out to be the best American battleships ever built.

The 12-7.5in gun cruiser design works

I just did a preliminary run of my program with the design that I proposed. The dimensions are 665ft x 66ft x 23ft with a normal displacement of 13,620 tons. The coefficients are Cp=0.56 and Cm=0.84. The power plant is 90,000 SHP for a speed of 32 knots at normal load. I was able to have a 4in belt, barbettes and turrets, with 3in + 2in decks. The metacentric height at normal load is 3.86 ft. The range at a normal load, with 1,000 tons of fuel is 4,709 nm at 15 knots. The range with 2,700 tons of fuel, at 15 knots, is 12,715 nm. The full load displacement is 15,976 tons. The speed at full load displacement is 30.8 knots. The armament is 12-7.5in/50 and 8-4.7in/50 guns. The 4.7in/50 guns are DP. The design includes a catapult and hanger.

A cruiser with 12-7.5in/50 guns would make sense

The 7.5in/50 gun still has merit for a 1921 ship. The gun needs to be mounted in a turret. I would prefer a triple turret, rather than twin. The 7.5in/50 Mk.III weighed 15 tons 9 cwt and 3 qrs. The AP shot was 200 lbs. The rate of fire was 5 rounds per minute. I would put the gun on a 13,500 ton ship with a speed of 32 knots. The primary role would be commerce protection, although I could see a role in fleet actions, or at least in detached task forces (as they came to be known in WW II). I would retain a secondary armament of 8-4.7in/50 guns. I would have a 4in belt. If I didn't say, the ship would be built for the British navy.

Calculating the rudder post position

I have a factor that I use to determine the postion of the rudder post. I take the waterline length and divide by 1.045. That seems to give a good rudder post position. I have been using this for the last 3-1/2 years. Not actually having built and run a ship, it is somewhat hard to know if this is a reasonable thing, but it is based on some example ships that were sufficiently maneuverable.

I just ran my program for my 9.2in/50 gunned cruiser

It is a little problemmatic to try and build a spec for a ship without a drawing, but I did it anyway. The Washington Naval Treaty Standard displacement was 16,036 tons. I was able to give the ship 9-9.2in/50 and 8-4.7in/50 guns, a 6in belt, a 3in deck, and 32 knots of speed. The normal displacement ended up as 17,861 tons. The dimensions are 670ft x 75ft x 23.6ft. The coefficients are Cp=0.585 and Cm=0.9. The ship is flush-decked with a 120,000 SHP machinery plant.

I still believe that there is room for a 9.2in gun ship for the 1921 building program

The British 9.2in/50 gun was a pretty effective gun, with a good range and rate of fire (4 rounds per minute). The AP shot weight was 380 lbs. The piece weighed 28 tons. My preference would be for a 17,000 ton ship with 9-9.2in/50 guns and a 4.7in/50 secondary armament. I would like to see a 6in belt and a 3in deck on such a ship, and a maximum speed, at normal displacement, of 32 knots.

In the early 1900's William Hovgaard suggested that the best battleship would be large and fast, with good armor and guns

William Hovgaard's crystal ball was pretty accurate. About 30 0r 35 years early, he predicted the fast battleship (or at least recommended it as the best bargain). Don't build battlecruisers, but build "battleship-cruisers", which would be fast, have the biggest guns and the heaviest armor. New developments and larger ships would make the older ships less capable, and they would then be used as ordinary battleships. Why build inferior ships when time would produce them, anyway.

Battleships and Battlecruisers

In effect, the fast battleships built in the 1930's and 1940's were battlecruisers with a new name. The North Carolina class ships definitely sacrificed protection to achieve speed and a heavy armament. They also sacrificed structural strength and ridigidy in the process. Except for their armament layout, the 1921 British battlecruisers (the G3 design) were better than most of the ships built as fast battleships. They sacrificed gunpower to achieve speed and protection. While the corresponding battleships would have carried 9-18in guns, the G3's had 9-16in guns. Due to the frenzy to achieve the most on a given displacement that was rampant in Britain in 1921, the armament layout was strange. They would have not given up that much by having a more conventional layout (two turrets forward, one aft), and they would have been superior ships.

SpringSharp

A business associate pointed out a website and warship general design program: SpringSharp.com. They started with the SpringStyle code and greatly improved the program (according to all accounts). The new program is a .NET Windows program. By all indications, this will be interesting to try. I can understand that they are keeping the source code to themselves, as there always might be a commercial value to this sort of work. I will evaluate the program to see if I might learn anything I could use.

WWII-era cruisers were largely "belted cruisers"

From the 1920's on, most cruisers had such a narrow swatch of armor that they had become "belted cruisers", along the lines of the Orlando class ships. The belt was covered by a deck, and the belt was almost submerged, being essentially one deck high. The British cruisers tended to have more coverage, in that they had armor that rose above the machinery spaces on the side, for a shorter distance than was covered at the waterline. As ships were increasingly overweight, much as in the 1880's, the belt was almost totally submerged. In the British case, the only part that had much above-water coverage was that above the machinery spaces. You can see it on the Edinburgh, Southampton, and Dido class ships, as well as others.

An amusing exercise: "modernizing ironclads"

I have been looking through my journal for 1999, which contains many ship drawings. One feature of early 1999 were my drawings of "modernized ironclads". "Modernized" almost doesn't do justice to what I did. For example, there is a ship with a tower foremast, a single funnel, flush deck, anti-aircraft guns, and a modern-looking flush decked hull. The bow is flared, and there are two stockless anchors. There is a ship labeled: "Inflexible", as if this were a ship with 4-16in guns (now BL, not MLR), 6-secondary guns, and 40mm and 20mm AA guns. On an earlier page are shps named "Shannon" (like the original belted cruiser) and "Narcissus", another cruiser. Then, there is a ship that looks rather WWII-like, but labelled "Southampton", and obviously a light cruiser built to something like the dimensions of the British pre-WWI light cruiser. The armament is 9-6in/50 guns, with two triple turrets forward and one aft.

I am pushing the upper limits on ship size

When I just tried to see what the top end for the very large battleship with 21in guns was, I ended up with a Reynolds number above 5.99x10^9! I need to add some more data for Schoenherr frictional resistance coefficients. I tried increasing the power to 350,000 SHP. To actually do that requires 6 shafts, as there is the approximate limit of 70,000 SHP per shaft. Above that loading, the shaft will fail. So to increase power to 350,000 SHP requires 6 shafts with 58,333-1/3 SHP per shaft.

The very large battleship design

I found out that the very large battleship, at higher speeds had a Reynolds number on the order of 5.6x10^9. My Schoenherr table, before this morning, only had values up to 4.999x10^9. I extended the table, and that solved the problem I was seeing last night. I had to turn on some printing so that I could see what was happening and what I needed to do to fix the problem. For Reynolds numbers above 5.0x10^9, the frictional resistance ended up as zero.

I can see now how I can improve the modeling of superstructure, so that I can get better stability calculation results. I also need to account for the heavy rangefinder and main battery fire control director mounted very high on a tower mast.

The optimal super-large battleship

I spent much of 1999 drawing very large battleships and battlecruisers. I just opened a record book to a page that has a large battleship drawing with some specifications. The ship carries 9-21in/45, 12-6in/50, 8-4inAA, and 44-40mm AA guns. The displacement is given as 115,000 tons. The speed given is 31 knots. The armor mentioned was 17in belt and 7in + 4in decks. I did a few calculations with the BigGun program and designed the 21in/45 gun. The muzzle velocity is 2,575 ft/sec, and the AP shot is 5,000 lbs. The piece weighs 311 tons. That is using my design coefficients, and may be heavier than someone else's design. The question is: how well does this design stand up with the preliminary design program? I had some sort of problem on my first run, but one goodie is that the triple 21in gun barbette is 45 ft in diameter. I suspect that some table lookup in the power calculations was out of range for a ship of this size! If I give a power of 190,000 SHP, the expected speed is 29.6 knots. The normal displacement is 108,008 tons. I should probably be able to tell what the issue is, with a little debugging, sometime tomorrow.

Cruisers and torpedoes

As long ago as the Spanish American War, naval officers realized that carrying torpedo tubes above water on cruisers was extremely hazardous. The conventional response was to carry below-water torpedo tubes on the larger cruisers. The smaller scouts carried torpedo tubes almost like they were destroyers. The modern light cruisers, such as the Arethusa, carried substantial above-water torpedo armaments during World War One. They were frequently used in action, with some success. By the 1930's, the US Navy had removed torpedo tubes from their cruisers. The only exceptions were the Omaha's and the Atlanta class. The British never removed their torpedo tubes, while the Japanese carried highly effective and sophisticated torpedo armaments on their cruisers, especially the heavy cruisers. They proved their effectiveness at Savo Island and other battles. The Allies, especially the Americans, were shocked by the range and effectiveness of the Japanese 24in Long Lance torpedoes. At one point, the Americans actually were considering remounting torpedoes on 6in and 8in cruisers. It only happened post war, however, and only as ASW weapons.