Glorious French cruisers

[ctwaterman]

What would be a reasonable Recoil obviously 1.00+ limits one to end only fireing but was would be reasonable on  Battle Ship.

Recently I designed a ship I really like but I had to add Bulges and Beam to get a reasonable steadiness and Recoil out of the ship.  Im still working on Improving the Design.

[Sachmle]

IMHO anything over 0.80 is pushing it as I presume that flooding during battle will cause a that to raise and very shortly you'll be unable to fire on the beam.

[ctwaterman]

Ah... good to know so maybe I have fixed the problem and next time I go into SS to check I think I finaly got it down to around .75

[Kaiser Kirk]

...while Graf Spee with T3 280 was 21.6m...

... & 20.69m for the Panzerschiff Deutschland.

I use a little coffee table type book for quick references, so I had Graff Spee's stats, but not her sisters.

Using Lutzow as the reference for minimum beam makes sense.

[P3D]

Hm, I did not notice the bulges, so I'd say the ship is unfeasible. As you might already know I consider their use an abuse of SS2 deficiencies. To have any margin of stability (too much of tumblehome) the ship must have an internal belt at 17m beam -i.e. ~30% of the below water hull is unprotected from shells. Shells would most probably explode within the fuel rupturing the weak internal bulkheads and hull plating by the unattenuated shockwave  - machinery and magazine spaces would be flooded by not seawater but fuel oil.

And the bulges have to be full with fuel oil, their volume is less than the total fuel capacity.

[Sachmle]

Hm, I did not notice the bulges, so I'd say the ship is unfeasible. As you might already know I consider their use an abuse of SS2 deficiencies

The way SS figures bulges is only an 'abuse' if one presumes that the bulges go all the way up to deck level. If they are to be presumed similar to those used on the US "Standards" in their rebuilds, i.e. from the keel to about 1 deck above WL, as seen here:



Then the lack of SS figuring extra deck armor to cover 'over' the bulges is irrelevant.

[P3D]

Sachmle, the US Standards are not that good as comparison. There you have 9-12' bulges on 95-97' (10-13% of beam), not that much change compared to 16' on 56' (25%). The problem is about stability at larger roll angles of tumblehome/bulged hulls. The righting moment is decreasing with the increased roll angle. In case of bulges, you have a sharp drop in the righting moment when the top of the bulge submerges. If the top of the bulge is 1m above water, this happens at a mere 5 degrees of roll. Your max angle of inclination (after which the ship would capsize) would be unacceptably low.
That the ship has 2m draft difference between light and full displacement does not help either.

I might just make some detailed calculation to show this.

[Sachmle]

That the ship has 2m draft difference between light and full displacement does not help either.

You've made statements similar to this on other ships, and while I'm well aware that a fully loaded ship will sit lower in the water then one at normal displacement, I've yet to see were SS lists the "Full load draft", therefore I presume you've some formula/rule of thumb for coming to your conclusion on full load draft, in this case 2m deeper. Care to share that information, would be useful.

[Carthaginian]

I might just make some detailed calculation to show this.

Sharing that might help ALL of us understand the mysteries of shipbuilding better.
Please share... I'm with Sam, if it'll make our ships better we need it!

[P3D]

If you increase the load of the ship by L tons, the ship displacement will increase by the same amount.
Assuming wall (vertical) sided ship, the chance of displacement = waterplane area x change in draught.

This is the time when SI is your friend, as 1m3 of seawater (1020 to 1025 kg/m3) is about 1 long ton (1016kg). So draught change  (in meters) = displacement change (t) / waterplane area (sq. m).

In imperial units, copypasting from wiki, "one long ton equals 2,240 pounds (1,016.0469088 kg) or 35 cubic feet (0.99108963072 m3) of salt water with a density of 64 lb/ft3 (1.025 g/ml)".

In this case, waterplane area is 2,206 sq. m. You have 5200t difference between light and full displacement. Draught change = 5200/2200 ~ 2.35 m.
As a note, SS2 assumes that the bulge is below water. If it continues above water, the waterplane area would be ~2800 sq.m.  

[Sachmle]

You have 5200t difference between light and full displacement.

Ahh..see, I knew I was missing something. But...so were you. SS Draft is Normal draft, not light. SO the change in tonnage from Normal to Full is only 1922t which gives a change in draft from normal (7m) to Full of 0.87m. This is marginal IMHO.

[P3D]

You have 5200t difference between light and full displacement.

Ahh..see, I knew I was missing something. But...so were you. SS Draft is Normal draft, not light. SO the change in tonnage from Normal to Full is only 1922t which gives a change in draft from normal (7m) to Full of 0.87m. This is marginal IMHO.

The draft change is the about the same ~2m regardless of what is the normal draft. That means if you design the ship to have adequate stability at normal displacement it might not be stable at light, and would be rolling too fast at full displacement. Merchant ships deal with such changes easily as they don't have much topweight, esp. compared to warships.

[Sachmle]

The draft change is the about the same ~2m regardless of what is the normal draft. That means if you design the ship to have adequate stability at normal displacement it might not be stable at light, and would be rolling too fast at full displacement. Merchant ships deal with such changes easily as they don't have much topweight, esp. compared to warships.

Yes, thank God we don't have to worry about any of that stuff since we use Springsharp, and it drives the physics of our pretend world. All we have to do is worry about stability, steadiness, seakeeping, cross-sectional, and overall strength. If we had to worry about all that other 'real world' stuff we'd never design anything different from what was really built. That would be boring..I'm glad this isn't real life.

[The Rock Doctor]

I'm not so keen on the bulges here - it just seems like a way to get a large hull without a matching amount of deck armor.

[Sachmle]

I'm not so keen on the bulges here - it just seems like a way to get a large hull without a matching amount of deck armor.

Agreed, just trying to make a point on Nverse vs Real World. I'm not that worried about the deck armor, as the bulges (as pointed out by P3D) don't add to the deck area, they don't even come up to the deck. Myself, I view them as stop gaps that can be added to already built ships in lieu of a TDS. Add bulge, reset speed to previous SHP, Unless new engines are installed, cut range until bunkerage matches original. Viola, finished...no using the 'extra' hull strength, no re trimming..unless you pay for the rebuild to allow that. You gain some stability, steadiness, and ability to absorb torpedoes(slightly) while costing yourself speed and range(Unless installing newer engines and paying the price for it.)