Ice Shield or Ice Armour is the weakest armour in the game and is not recommended for protection unless it's an only choice. Ice Armour is good for protecting against swords because it is very thick. Although Ice Armour is almost always used for the bottom of ships to give it the ability to move during Building Mode.
Steel Armour is unlocked after ice armour and is good for new players because of its cost-efficiency ratio. However, it is still very weak and can easily be destroyed with focused gunfire. Steel Armour is not very good when fighting experienced players.
Goldenhare Armour is very good and very tough. When fighting experienced players, one can actually have a chance with this armour. Goldenhare Armour is very cost-efficient and light enough for tons upon tons of it. Gold Armour should be used by all that have access to it as their best Armour type.
Bluesteel Armour is very tough but also a bit expensive. Bluesteel Armour is one of the best in the game because of its lack of weight and good toughness. In summary, Bluesteel Armour is just Goldenhare Armour but thicker, quite a bit tougher, and more expensive.
Redsteel Armour is the second toughest armour in the game but is very expensive and heavy. Redsteel Armour should be used with lots of wood so that your boat does not completely fall apart into the depths of the ocean. Otherwise, Redsteel is tough. If your boat can take it, then you should use Redsteel Armour.
Behold, the toughest armour in the game. This stuff is almost mathematically indestructible and it takes almost an entire round to remove one piece of it. Mauvlar Armour is extraordinary light and extremely tough, great for any ship.