The simple way to find a multiplayer server is via the Steam Client > View > Servers > The Ship. Hey presto, you're done! :)
Here's a more detailed way of adding a server manually: http://steamcommunity.com/app/2400/discussions/0/613940477638201994/
On behalf of the team at Blazing Griffin, we hope you enjoy The Ship.
We have a couple of other games on sale this week that you might be interested in:
The Nightmare Cooperative
A quirky little turn-based rogulike puzzler, currently reduced to £1.67 / $2.03.
http://store.steampowered.com/app/310070/
Gentlemen!
A frantic local coop game, currently reduced to £1.74 / $2.49.
http://store.steampowered.com/app/253570/
Also our new roguelike meets space-RTS:
Distant Star: Revenant Fleet
http://store.steampowered.com/app/335830/
- the Blazing Griffin team