Wounded ships slowing down?

[Walruss]

Hey guys, me again...
Just hit a convoy, scored about 4 hits (of 7 torps i had left), I'm currently playing hide and go seek with the convoy's destroyer, but when I've convinced him I'm dead, I'd like to go finish up the freighters I hit.... IF they slow down? To my mind, taking even one torp below the water line is going to slow you up... but does it in the game? No hits far aft near the engin room I don't think (which is a pity), hits scored were on:
3 liberty cargo
1 med. ranger tanker

one hit each

mods list:
BRF 1.3 full
IRAI_0_0_11
NEWUIs_TDC_3_5_1
+ colouredshippingchat or above
Sub_exhaust_1_0_4
NewUIs_TDC_3_5_1_jimimadrids_map_tools
Sobers base wave
U-boat Historical Specs
MoraleFix
TorpFix

[TheDarkWraith]

Originally Posted by Walruss

Hey guys, me again...
Just hit a convoy, scored about 4 hits (of 7 torps i had left), I'm currently playing hide and go seek with the convoy's destroyer, but when I've convinced him I'm dead, I'd like to go finish up the freighters I hit.... IF they slow down? To my mind, taking even one torp below the water line is going to slow you up... but does it in the game? No hits far aft near the engin room I don't think (which is a pity), hits scored were on:
3 liberty cargo
1 med. ranger tanker

one hit each

mods list:
BRF 1.3 full
IRAI_0_0_11
NEWUIs_TDC_3_5_1
+ colouredshippingchat or above
Sub_exhaust_1_0_4
NewUIs_TDC_3_5_1_jimimadrids_map_tools
Sobers base wave
U-boat Historical Specs
MoraleFix
TorpFix

you've given me a great idea to add to IRAI with this. I can add a 'damaged' state to the ship that will cause it's speed to slow when the damage is > x%

[Nisgeis]

Originally Posted by Walruss

I'd like to go finish up the freighters I hit.... IF they slow down? To my mind, taking even one torp below the water line is going to slow you up... but does it in the game? No hits far aft near the engin room I don't think (which is a pity)

In the stock game the ships will stop if you destroy their engines (in theory - not sure anyone hjas actually tested that!), or if you damage them to a general overall damage level of 70% they will drop their speed to 30% of the convoy speed. If you get the to 90% damage they abandon ship and become dead in the water waiting for your merciful coup de grace. There was a mod out that increased the scope of the damage and speed, so they'd slow down at different lighter damage levels, but I can't emember of the top of my head what it was called - it was released quite early on and was well received for its effects.

It was called 'The Damage Assessment mod'.

[Seaman_Hornsby]

Originally Posted by Nisgeis

It was called 'The Damage Assessment mod'.

Yep, Arclight's work:

http://www.subsim.com/radioroom/showthread.php?t=165771

[Nisgeis]

Ah, I thought it was Arclight, but thought I'd better not say that incase I put my foot in it :-). Thanks for posting the link!

[Seaman_Hornsby]

No problem, happy to help.

[Arclight]

Originally Posted by TheDarkWraith

you've given me a great idea to add to IRAI with this. I can add a 'damaged' state to the ship that will cause it's speed to slow when the damage is > x%

Oh thanks, it's nice to know ones work is noticed.

[Walruss]

@ Wraith and arclight yeah... be interesting to what percentage you'd put it.... I mean a small calibre hit from a deck gun might not cause need for a ship to slow.... but a torpedo has got to weaken the structural integrity of most merchants at least, enough so that full speed isn't possible... and next time I'll aim aft when I'm low on torps and want to isolate ships from the pack.

[Arclight]

Even if it's just holes from the deckgun, the pressure of the water from moving fast through the water would be very high. In order to get the flooding under control and patch the holes, as far as I know, a captain would be wise to slow his ship.

These are the thresholds I used:

Slow to 50% speed at 25% damage (damage assessment)
Slow to 20% speed at 65% damage (damage control)
Abandon ship at 85% damage

All sensor effectiveness reduced to 70% while in "damage assessment" state to simulate sending some crewmembers to investigate, captain focusing on getting the damage under control, shock from being hit, etc.


The idea is the captain slowing his ship to avoid damaging it further, not knowing the full extent of the damage. You could consider using the deckgun to trigger the slowdown a bit of a cheat, but then I don't think many Kaleuns would start an attack with the deckgun; you'd need half yer ammo supply or more to sink a ship.

[Karasunx]

Originally Posted by Arclight

You could consider using the deckgun to trigger the slowdown a bit of a cheat, but then I don't think many Kaleuns would start an attack with the deckgun; you'd need half yer ammo supply or more to sink a ship.

I thought it was a common practice in the start of the war on lone unarmed merchants that U-boat captains would use only their deckgun. The reason being that shells were cheaper and more plentiful than torpedoes. I might be thinking of the first World War before Germany started practicing unrestricted submarine warfare.

[Arclight]

You may well be right, not quite sure. Just makes more sense to me to use it to finish off merchants that have already been torpedoed.

It might be they just used the gun on smaller merchants, but there really arent any of those in SH5. It's mostly 7000 tons and over. There's 1 type of smaller merchant and 1 small tanker, those are pretty good targets to dispatch with the gun. But 7000 tons is a lot of ship to sink with just the deckgun.

[karamazovnew]

Actually...

The quantity of water that will rush through the hole in the hull depends on 3 things:

- size of the hole: most torpedo hits will create very large holes in the hull bigger than 2 meters squared. These CAN NOT be fixed on the go from the inside. The ship would need to stop, a Macarov patch would be applied from the outside and the gap plugged with cement from the inside.

- how far under the waterline the hole is: the further down it is, the higher the water pressure. Captains will usually pump out all ballast to keep the ship as high in the water as possible.

- position of the hole, speed of ship and turning rate: a hole at the forepeak (in front of the first bulkhead) would not affect the ship much. If the front bulkhead is affected, it's actually better to stop and reverse the ship. But, if the hole is near the waterline, going moderately fast and ballasting the stern would bring the affected section out of the water Now in all cases of holes except on the bow section, it's actually better to go as fast as you can. This depends a lot on the shape of the hull. Faster speeds will disrupt the laminar flow around the ship. On some holes it's best to have laminar flow (on narrow vertical breaches) while on others it's best to have turbulent flow (low pressure). Constantly turning into the affected area would do 2 things: rise the level of the hole and reduce pressure in the area. However, if the ship continues to take on water, the ship might capsize. A hole near the keel will either break up the keel in rough weather or at high speed and the intake of water would practically be impossible to control. You'd have to shut off that compartment and allow it to fill up to the waterline if you can't patch it with a Macarov. The type of cargo that you carry in that compartment will dictate if it's better do dump it overboard or not.

So as you can see, simply reducing speed isn't always the best way.

Now, in a mid-Atlantic 1940's situation, if you're hit by a torpedo near the keel or a bulkhead, it's pretty much game over.

[Karasunx]

Wow, thanks Karamazovnew. That's some good info to keep in mind, I always heard to aim at or below the keel for torpedoing but didn't really know why.

[Arclight]

Interesting, thanks.

Question though: wouldn't a captain need to determine the extend of the damage before deciding which actions to take for damage-control? What would be his immediate response to a torpedo impact?

[karamazovnew]

Originally Posted by Arclight

Interesting, thanks.

Question though: wouldn't a captain need to determine the extend of the damage before deciding which actions to take for damage-control? What would be his immediate response to a torpedo impact?

Well, they don't teach us THAT at navy school .
However normal procedures are to send somebody to investigate the full extent of the damage before taking any decisions. If I'm in a convoy, I would not start to turn wildly or change speed, as that would cause problems to the other ships. If I'm traveling alone, and I'm up on deck and I can see the impact point AND the hit is favorable I'd most likely order a full ahead and turn into the direction of the hit. If I loose the engines (loosing a propeller also means busting up your prop shaft and over-reving your engines) I'd order an immediate evacuation on the side opposite of the hit.

The problem in SH is that ships behave like go-carts. They accelerate too fast and turn much too quickly. It's one of the major problems I have with the game. It's almost impossible to calculate how a ship behaves through formulas, that's why they still use model tests and sea trials to generate all the final speed and maneuvering tables and graphs. HOWEVER, the basic formulas are enough to create good characteristics based on hull shape, mass (and dynamic draft) and engine power (and prop type and number). Simply taking a few static values from a cfg file is not a good idea. They should've built an simple application which allowed splines to be used to generate the ship characteristics. Oh well, dreaming with my eyes open...