Overweight Ship Design

[tortugapower]

I didn't realize this until now, but the game allows you to build ships which are slightly overweight. Is this a bug, or are there some hidden negative modifiers for doing so?

Thanks in advance!
~ Tort

[rockmedic109]

Working as intended. I think there might be some speed issues {I don't know} and I've read that they are slightly easier to sink.....AFAIK, the ship sinks when the weight of the incoming water is greater than the rated displacement and the overweight adds to the weight of incoming water.

[tortugapower]

Thanks rockmedic. This could change the way I do ship designing, hmm... If anyone knows more about the negative modifiers, I'm all ears!

[randomizer]

If I recall correctly, building overweight designs increases the probability that the ships will not reach design speed (because they're over design displacement for their engines) and may be more susceptible to being lost through flotation damage as their exceeded design displacement affects stability. So you need to weigh the cost/benefits of producing overweight designs.

[julianbarker]

The game allows it because some nations, like Russia, habitually built ships that were overweight. Being significant underweight head corresponding advantages. For example, the ship will have reserve buoyancy.

[oldpop2000]

Jan 8, 2016 0:10:40 GMT -6 julianbarker said:

The game allows it because some nations, like Russia, habitually built ships that were overweight. Being significant underweight head corresponding advantages. Fit example, the ship will have reserve buoyancy.

Russian ships were built on French designs then modified.  The Russians overloaded their ships with coal and supplies, high up in the structure which significantly changed the stability of the ship. Their machinery weight might have been higher than corresponding French machinery also, hull/machinery is one of top contributors displacement.

[constans]

Jan 8, 2016 0:10:40 GMT -6 julianbarker said:

Being significant underweight head corresponding advantages. Fit example, the ship will have reserve buoyancy.

Is this actually modelled in the game?

[janekk]

Can someone confirm? Are there benefits for leaving spare displacement or should I just load up as much as I can with spare ammo? I imagine it would somehow translate into more flooding damage capacity but it would be nice to know for sure. Would it also affect chance of exceeding / not reaching design speed in proportional fashion or is it just a matter of ticking overweight / not overweight checkbox?

[fredsanford]

In my experience having reserve tonnage helps. Couple of benefits:

Reserve buoyancy
Better chance of getting the "exceeds design speed" event
Less chance of getting "can't make speed/slightly overweight" events
Room for modifications

I'll try to leave 30ish tons for B, getting up to 50-75 for a 1920s BB

[jwsmith26]

I try to build all of my battleships to the same speed - 22 kts. After getting a lot of events that lowered the speed on my battleships to 21 knots, I started leaving about 1% of free tonnage, hoping this would affect this event positively. So for a 35,000 ton dreadnought I'd leave 350 tons free, which is really quite painful to do.  I've tried this through three games now. Unfortunately, I still get events that lower my speed. In the last game, out of 15 dreadnoughts I built, 3 were reduced to 21 knots. Three games is a pretty thin sampling but to me it didn't appear that leaving even this much free tonnage had an appreciable effect on this event. 

It now seems that I can't really affect this event much, so instead of trying to influence the event I've started building ships 1 knot faster than I want them to end up at. It's more expensive but applying that 1% of spare tonnage I was throwing away goes a ways to paying for the extra tonnage required by the extra knot of speed. 

It would definitely be nice to know what, if any, effect over or under weight has on this event. 

[director]

I always add 1 knot to my intended formation speed and usually leave 120-150 tons reserve. That's not too painful and it does permit me to add better fire control later. I almost never get the 'cant make designed speed' event.

[chz]

I don't think there's any benefit to a reserve on a ship that you won't rebuild at some point. Which means it matters most on your cruisers. It's rare to completely rebuild a BB, due to costs. Normally you're just adding modern fire control to it, or at best replacing -1 guns with +1 guns. Machinery refits are just too long and costly. CAs, if they have some spare tonnage, can easily be rebuilt into modern, useful combatants. The spare tonnage is to allow a decent speed out of them. Replace those twin 9/10" guns with triple 6" mounts, bump the speed up to 28/29 knots, and they're pretty good. If you don't have to spare tonnage to put in engines that can outrun (most) BCs, it's not worth the time. Fleet CLs (vs. disposable raider) can always benefit from a speed boost as well.

As an example, I have an 1899 7100t AH CA with no reserve buoyancy. I can rebuild it up to 27 kts (from 22) and double 6" turrets (from single 9"). Drop the secondaries to 4" (from 6), put them in twin turrets. That's a competent heavy cruiser, albeit a bit under-armed. But hey, I was starting with 7100t and no reserve. At 27kts, it can't outrun everything that outguns it so I haven't really been eager to put it in the yard. But it's that or scrap it at this point. If there was extra reserve buoyancy, I could squeeze another knot or two out of it and it would be great.

Older CLs can get up to 30/31 kts. Newer ones close to that speed can get more firepower if they started with 5-6" guns in the first place. It let me replace single 6" mounts with double 5" mounts. Though I'm not sure 16 5" guns is very "light". But only because that design *did* have a fair bit of reserve and was already 29kts.

[fredsanford]

May 12, 2016 19:02:38 GMT -6 jwsmith26 said:

I try to build all of my battleships to the same speed - 22 kts. After getting a lot of events that lowered the speed on my battleships to 21 knots, I started leaving about 1% of free tonnage, hoping this would affect this event positively. So for a 35,000 ton dreadnought I'd leave 350 tons free, which is really quite painful to do.  I've tried this through three games now. Unfortunately, I still get events that lower my speed. In the last game, out of 15 dreadnoughts I built, 3 were reduced to 21 knots. Three games is a pretty thin sampling but to me it didn't appear that leaving even this much free tonnage had an appreciable effect on this event. 

It now seems that I can't really affect this event much, so instead of trying to influence the event I've started building ships 1 knot faster than I want them to end up at. It's more expensive but applying that 1% of spare tonnage I was throwing away goes a ways to paying for the extra tonnage required by the extra knot of speed. 

It would definitely be nice to know what, if any, effect over or under weight has on this event. 

Which nation?  I wonder if that matters.

[director]

As for machinery refits... if I have a good design that still is coal-powered I will sometimes rebuild the ship(s) for oil propulsion and either raise the speed or improve the armor. I did this with the Kraken-class battlecruisers in my Byzantium AAR. It was brutally expensive, but took (I think) 10 months instead of 28-30 for a new ship and extended their useful lives by many years.

[tbr]

OK, I had a look at this before. Overweight designs get a negative floatation modifier in the ship's stats. You can view these and other negative and positive modifiers (like ROF and accuracy modifiers due to heavy centerline etc.)in the ship files within the savegame folder.

With a slightly overweight ship you will geat a "FloatMod" value such as this:

FloatMod=-175

There are no positive modifiers for ships with a weight reserve though, I have only seen negative modifiers or "FloatMod=0" here.