Bump * UPDATE *

After a useful discussion in the uboat.net forums (not conclusive though), I am:

a) Updating the mod with new, more conservative values. See first post.

b) Creating a "mirror" / alter ego mod (of the DG Removal) which models the additional drag caused by an upgrade to the conning tower, or ultimately the U-Flak configuration. Since I consider the U-Flak the queen of the U-boats, I will call the mod U-Flak Queen Drag :-j .

Have Fun!

VonHelsching

Hi!

Do you have any data or hydrodynamic simulations showing the effect of drag due to deck gun, conning tower, and/or changes in flak configuration? Any source that I have found states the guns were removed to obtain a "modest" reduction in drag, but fails to mention how much this affected the u-boat's underwater speed, or the extent to which it may have offset the increased drag due to the proliferation of anti-aircraft weapons and supporting superstructure.

This seems like an good idea; unfortunately, I have found no data either on line or in books to back up any change in the way the game models a u-boats underwater performance.

Pablo

What about underwater range, I haven't seen that mentioned.

I think people here are forgetting that drag increases with speed. You can't really say "hey, removing the deck gun should gain you x speed" Physics doesn't work that way. If you can get the boat to go fast enough, at some point the drag reduction will be noticed. The question is: is this point within the top speed of the boat? I would bet that at slow speed, the removal would have almost no impact. At flank ahead (7 knots), I'm not sure, but you would defanetly be more likely to see the impact. Anyway, I don't think the game engine allows you to model the impact of variable speed differences well, does it?

I wish I had some data. The figures I used are common sense guesstimates. I have also been told about subtle but noticable figures and I translate this as a figure between 2% and 5%. For this version I chose 3% at least for the turn radius and for speed less than 5%.

The general idea here is not the values per se, but the psychological / gameplay effect to the player that *something* has changed, even if this is a minute change, as opposed to the stock game, where *nothing* changes.

I've done some systems engineering graduate courses some years ago, but not being of a science / engineering backgroung didn't help much apart from a gerneral "feeling" about systems. But, from what I remember, you must be right. At normal speed this should have no impact whatsoever; the effect only being visible at max speed.

The game does allow fine tuning the % of max speed per gear (speeds 1-slow to 5-flank) and this is can be easily modded. I just thought that it wasn't worth it. I mean, in speed 2-halbe vahrt the additional speed should be less than 0,1 on an IX type. The effect of fatigue of your engine room crew probably is a more significant factor in speed (or the variability of it), than this mod. Anyway, good point.

Regarding underwater range, I wish I had some more data. Would be more than happy to incorporate them.

I just read in the book "Unterseebootbau" (Connstruction of U-Boats) by Ulrich Gabler that the drag of a streamlined U-Boat with a submerged displacement of 500 tons is increased by 30% if the periscope is fully extended. The drag increase was measured at 4 knots.
He doesn't mention it clearly but he must be talking about post war U-Boats with a very well designed hull, surely a submarine and not a 'Tauchboot' like the U-Boats in the second world war (except Type XXI).
Unfortunately there is not more info on this special topic in the book.

For the U-Boats we are talking about 30% would be way to much because these U-Boats are far less streamlined than modern U-Boats. But I think (just a feeling) a drag penalty for the deck gun of 3-5% seems ok for me, so the speed increase should be ok.

Cheers
Mr. Fleck