I had a lot of fun with HMS Marulken and the crew. It was a unique experience where gaming was concerned, and got me back into submarine simming. I had played them ever since the first one, as far as I know, came out (Microprose's original "Silent Service", on the Sinclair Spectrum). Life got in the way around about 1996, and I stopped regular gaming for years, only picking up gaming again recently. Up until that time when I abstained, other sub sims I had played were "Silent Service II", "688 Attack Sub", "Red Storm Rising", and "Aces of the Deep", as well as programming my own ASW game on the Commodore Amiga in the programming language AMOS.

In short, I was well into it, as well as being a complete naval warfare geek.

I also used to read avidly about the subject. Playing HMS Marulken also revived that habit, and only a few days ago I finished reading an exciting story about the war patrols in the Malacca Strait of the RN "T" Class submarine, HMS Tally Ho, in the book "The Hunting Submarine". Tally Ho had an unusually successful series of patrols commanded by Lt. Commander Leslie Bennington, for a British sub operating under the restrictions of the Washington Treaty, and even succeeded in sinking the IJN light cruiser Kuma. It was also involved in a collision with a Japanese torpedo boat, the Hayabusa, and survived in a surface action that would have made Naro proud! I scoured around and found these pictures from the Imperial War Museum site of Bennington, the captain, holding a piece of the Japanese boat's propeller, and the damage to the Tally Ho as a result of the collision. plus a shot of the sub and crew. Great stuff! Totally awesome book, worth the read for those who like submarines.

TALLY HO LIMPS HOME. 9 MARCH 1944, COLOMBO, CEYLON. THE RETURN TO PORT OF THE SUBMARINE TALLY HO AFTER A SUCCESSFUL PATROL DURING WHICH SHE SUSTAINED DAMAGE WHEN A JAPANESE TORPEDO BOAT CRASHED INTO HER.. © IWM (A 22886) IWM Non Commercial Licence

TALLY HO LIMPS HOME. 9 MARCH 1944, COLOMBO, CEYLON. THE RETURN TO PORT OF THE SUBMARINE TALLY HO AFTER A SUCCESSFUL PATROL DURING WHICH SHE SUSTAINED DAMAGE WHEN A JAPANESE TORPEDO BOAT CRASHED INTO HER.. © IWM (A 22887) IWM Non Commercial Licence

TALLY-HO BACK FROM THE EAST. 27 JANUARY 1945, BLYTHE. THE ARRIVAL HOME OF HM SUBMARINE TALLY-HO AFTER DUTY WITH THE EASTERN FLEET.. © IWM (A 27110) IWM Non Commercial Licence

HMS TALLY HO, BRITISH T CLASS SUBMARINE. 20 NOVEMBER 1945, ON BOARD THE AIRCRAFT CARRIER HMS INDOMITABLE.. © IWM (A 31033) IWM Non Commercial Licence

So inspired I have been that I went and got Silent Hunter III from Steam so I could do a bit more submarining. I chose SH3 with some trepidation, as I read reports that it doesn't like new GPU's. However, other reviews I read on the sim itself say it is the best of the series, and that SH4 and SH5 are a bit too "arcadey" by comparison. I took the chance and it paid off. SH3 works perfectly well on Windows 10, with an i7 processor, and an Nvidia GTX 970. Here are some shots from my training.







Finally, PC submarining with SH3 provided me an excellent and timely tool of opportunity to actively help a little somebody - who is having some trouble learning trigonometry - to get to grips with the subject in a fun way. I'll be posting some of the exercises I concocted in other posts on this thread in the very near future, once I clean up the diagrams a bit for publication. You're going to love it!

PS: For those posts that will follow, I admit to having had to dust off my old maths workbook that I have kept all these years, and spray some WD40 down my ear hole to deoxidize the cogs, LOL!

So, let it never be said a game cannot teach a kid something useful to pass an exam at school (results were out today, trigonometry was A-OK!).

Let's have some fun on board U-99 (with the utmost respect for the real crew of the original U-99)...

Captain Naro raised the observation periscope and peered laconically through the viewfinder. It was hot inside the hull of the submarine. They had been submerged for more than two hours, with Sweeper the sonar man on hydrophones tracking a contact. Sweat dripped off the brow of every man on the vessel as the CO2 level rose. Finally, Sweeper had said the contact should be in range to commence an attack phase. Naro had issued his orders to Magnet, the Engineering officer.

"Take us around to course 035, ahead 1/3. Periscope depth."

"035, 1/3, periscope depth", Magnet confirmed the order. There followed some creaking when the pressure on the hull changed as a result of the maneuvers. Everyone waited in silence. At long last, after what seemed an interminable amount of time, Magnet came back, "On course, periscope depth".

Naro now swung the scope around to the bearing Sweeper had provided, arms dangling over the handles and cap on back to front.

"Look at that. Target in sight. Looks like a Liberty class. Bearing 330, mast elevation 0.47 degrees. Wake up Cygon, what's the range?"

Cygon didn't move from the stool he was sitting on, back to everyone in front of the TDC. Tracer booted his leg and he jumped up with a strained sigh and blinked hard to get his eyes back into focus.

"Huh?"

"Hey, target Liberty ship, elevation 0.47."

Cygon grabbed his slide rule, fiddled with it while holding it at arm's length, and after a couple of seconds replied, "Range near as darn it 2,800 meters".

"All stop," Naro ordered. Magnet replied as customary and a moment later the hum of the electric motors, perceivable in the control room, stopped.

"Mark. Take time, NOW. Scope down. We've caught him just off the zig, so we can give it ten minutes."

They waited. Sweeper presently peered out of his sonar room cubicle,

"What's going on, damn it!"

"Shhh!"

Tick, tick, tick, tick, tick...

"OK, scope up. Let's see... Bearing 045, elevation 0.7 degrees. Down scope. What's the target range and speed?"

"Ah. Give me a moment," the slide rule was noisy this time. "Range, 1,900 meters. Target speed, 4.8 meters per second. About 9 knots."

Naro didn't waste a second, "Magnet, take us down to 30 meters, course 060, all ahead full. Prepare tubes one and three. We're going in! Cygon, when you can give me a better intercept course!"

"Ho-hum. OK, Cap."

... to be continued ...

So, what happened?

Here's a diagram of the elevation sightings...



This one is easy. The mast height on a Liberty ship is 23 meters. Get out the scientific calculator, make sure trig functions are in degrees, and enter;

Mast Height / Sin (elevation)

23 / Sin (0.47)

Range = 2,804 meters

The next calculation is a bit more involved, to say the least, but some future ones get ridiculous by comparison...



The object of the two bearing marks are to calculate the target speed by change of bearing, with a known range, over a period of time. It is important to remember you are working with limited information based on your data collection, and the correct trigonometry rule should be selected for the purpose.

Now, yes. You can do what is suggested in HMS Marulken and divide the ship's length by the time it takes to cross the center index on the scope, but this method is only accurate when the ship is beam on (angle on bow 090 or 270, +/- 30º degrees). Beyond that, range change will hamper accurate speed deductions by this method.

First thing, get the angle between the bearings.

(360 - 330) + 45 = 75º

This is angle A.

Right. So now, enter the Law of Cosines;

a^2 = (b^2 + c^2) - (2 x b x c x Cos (A))

It will be a good idea to convert the range meters into kilometers at this point, if you do this manually on paper, or you are going to get ridiculously large numbers from the squaring, unless you use scientific notation. Input the data that you have into into the formula;

a^2 = (2.8^2 + 1.9^2) - (2 x 2.8 x 1.9 x Cos (75))

a^2 = (7.84 + 3.61) - (2 x 2.8 x 1.9 x 0.25882)

a^2 = 11.45 - 2.75

a^2 = 8.7

...because (a) is squared, the Square Root of the answer so far will give us the distance of (a)...

a = SqRt (8.7)

a = 2.95 km

Nice! The Liberty ship traveled 2.95 kilometers (2,950 meters) between the bearing, taken 10 minutes apart.

Now, for the speed, the easiest bit of the whole numeric shenanigan performed here. If the ship traveled 2,950 meters in 10 minutes, it travelled...

2,950 / 10 = 295

295 meters per minute, or...

295 / 60 = 4.9

4.9 meters per second. This is roughly 9 to 10 knots, each meter per second being more or less equivalent to 2 knots (that can help with DCS, too, as ATC gives the wind speed in meters per second).

It is a lot of work. I can only have the highest esteem for these guys during the two World Wars, who did this stuff again and again for every attack in such claustrophobic conditions. Respects...