Check out this map on youtube here.
This map is oriented around the UNSC Ghost Ship, one of the last water-based ships in service under the UNSC before they retire their watercraft in favor of the more versatile and capable spacecraft. The map has been thoroughly tested with lobbies of all sizes, and has been tweaked and perfected over time.
The Ghost Ship fires its main cannon at the attacking flood.
The humans will begin the round by grabbing a few weapons from the stockpile below deck, in an area directly next to where the humans spawn. Weapons up for grabs there include basic guns like the standard issue automatics and pistols, but also include some heavier stuff- a saw, a concussion rifle, and a railgun. All of the weapons regenerate themselves eventually, so if they run out of ammunition during the battle, the humans can head down below to fill up their weapons or exchange them. The weapons room, which is only a portion of the below deck area, is shown below.
After arming themselves, the spartans will then proceed through the chambers to a staircase, where they will rise through an opening in the deck. On the deck, there are several mounted turrets- two machine guns, two plasma turrets, and a high explosive 120mm naval gun (scorpion). The humans will occupy the turrets and prepare to repel the incoming flood, which will be attacking the ship from the port, forward, and starboard sides.
View from behind the vessel. Visible are the two plasma turrets, the main battery, and one of the mounted machine guns. Certainly not the ship's prettiest angle, but it's the only shot I have showing the flood's starboard attack vector.
The flood will spawn in a separate area within the cave. They will be marked by wayponts until they reach the ship so the humans will know where they are attacking from. Upon spawning, they will run through one of five man cannons, which will launch them through a low gravity zone towards the ship. The flood can maneuver left, right, forward, and backward to avoid incoming projectiles and make themselves harder to hit. The minimum time it takes for the flood to reach the ship after launch is about twelve seconds, giving the humans time to shoot them down on their way with one of the turrets or a handheld weapon.
The ship's crew use a variety of weapons to hold off the incoming flood
The flood damage resistance is increased, so while they aren't unreasonably powerful, they are still much harder to kill than the traditional flood. This gives the flood a chance to survive the storm of fire that they will face, and also serves to discourage players from camping below deck or in one of the buildings, and instead attempt to shoot them down before they reach the ship, and preferably utilize teamwork like an actual ship crew would. But in the event the flood do reach the ship, it is up to those still on foot to use their weapons to take out the flood before they can infect too many humans. There are also a few structures on the ship, as well as the area below deck, to spice up the onboard combat. If the spartans hide below deck the whole game, the flood will make it to the ship unopposed, and slaughter everyone with their increased health. (Also remember, though, that the flood can destroy the main turret with one slash, so you're not 100% safe inside of it.) All of this combat unfolds within the five minute time limit for each round.
The humans have suffered heavy losses after the flood bypassed their turret fire several times. The last few spartans must abandon their battle stations and run for their lives to avoid being slaughtered after the ship has been overwhelmed by flood.
The entire map was forged with aesthetics constantly in mind, and the weapons/turrets were chosen and placed very strategically to give the ship an amazing look while she's firing her weapons while also keeping the game balanced. Because the ship looks its best while the spartans are actively firing their weapons, I cannot completely capture its full glory through screenshots.
This map, Battleship, is best played with at least nine players, with the optimal number being around thirteen. Because most of the trait zones failed, I was forced to add a separate gametype, "Battleship"(halowaypoint.com/en-us/games/halo4/fileshare/details/e8e5f6fd-596a-4bdc-a04b-087d759d13a8) to tweak the health, damage, and other traits as necessary, so make sure to download that with the map.
Again, you can find videos for this map on Youtube here.