As Rule the Waves 3 is a game with a large focus on the evolution of naval ship design, the ship designer is at the heart of the game. RTW3 lets you design any ship from a small corvette up to the mightiest super-battleship. And not only does it cover a large range of ship sizes, it handles over 80 years of technological development in naval history, from 1890 to 1970. The technologies used to build ironclads powered by reciprocating steam engines in the 1890s were of course vastly different from the gas turbine powered missile cruisers of the 1970s. Technological development is realistically covered in the game and will set the limits for your ship designs.
Designing a French ironclad in the 1890s
When you design a ship, you should try to think of its role within the context of your navy. Take cruisers for example. If you have a nation with widespread colonies and interests around the world, you might consider a colonial cruiser. This would be equipped for colonial service, it would probably be best to optimize engines for reliability, and you would want it to have long range. That will cost weight, so it probably won’t be very fast, but you will get a sturdy workhorse that can show the flag in the colonies and still be useful when war comes.
A scout cruiser for the Imperial German Navy
On the other hand, there might be a need for dedicated fleet cruiser as a scout for the battle fleet. High speed is desirable, of course, but we can live with cramped accommodation and short range, as it will only be operating in home waters. We can even be bold and optimise engines for performance, accepting the risk of the occasional breakdown. This is the opposite of the workhorse above. Here we have the temperamental racehorse, optimised for one mission, but sensitive and picky.
Yet another cruiser type might be the raider. We would want reliable engines to be able to operate for long periods away from friendly bases, and long range is desirable. Speed should be enough to avoid heavy enemy patrolling ships, but we could build her strong enough to defeat what she cannot run from.
These considerations are similar for larger ships. If you are playing Austria-Hungary for example, you have no colonies and no interests outside the Mediterranean. You can go for smaller battleships with low range, cramped accommodation and low freeboard, thus saving weight to make them compact but capable. Keeping down the displacement keeps down costs, so you can build more of them, and you will hopefully be able to fight nations with far larger resources who have worldwide obligations that require them to equip ships for service anywhere in the world.
A British G3 type battlecruiser in the 1920s
There are some specialist ships that you should not neglect. The lowly 400-ton corvette is actually an essential unit in any navy. It can patrol the coasts against submarines and its presence in an area will reduce the risks of mine strikes for larger ships. Having a decent number of small corvettes avoids having to use destroyers as ASW patrols, which could denude the battle fleet of destroyers.
Another ship to consider for nations with large colonial interests is the colonial gunboat. This will be a corvette with 1500 tons displacement or so, equipped for colonial service. This makes it good for fulfilling obligations to have tonnage on foreign stations, freeing up cruisers. If equipped with a couple of 5 or 6 inch guns, it can even put up a fight against an enemy raiding light cruiser.
The Light and heavy cruiser types will morph into missile cruisers from the 1950s as missiles will start to dominate naval combat. Missile cruisers usually specialize in either the anti-aircraft role or the anti-surface role.
A missile cruiser for the US Navy
But new construction is not all that the ship designer can do. Old ships might need modernization to be able to extend their service life in your Navy, and the designer lets you rebuild ships, within realistic limits of course. You can modernize fire control, change the secondary battery to dual purpose guns, add light and medium AA guns, floatplanes and other similar equipment.
Ship design might seem complicated looking at the screenshots above, but do not worry, you need not design ships from scratch. The ship designer has a powerful auto-designer that will design any ship type for you. A usual method is to press the auto-design button until you see something that you like, and then modify that ship design to your taste. Another way is to start with an existing ship design and modify that to take advantage of new technology or adapt it to new threats.
Ship design in RTW3 sees you continuously develop your ships to give your Navy the tools it needs to prevail on the high seas. Naval combat will be the ultimate test of your designs.