While browsing Bnet, I found this: http://www.bungie.net/Online/Halo3UserContentDetails.aspx?h3fileid=95670109 [bungievid]95670109[/bungievid] Discuss.
It is possible. Here's a quick tutorial; Something cool is that all the immovalbe objects will float in the water. So, let a door float and settle in the water. Then, place a double box/container underneath that. The box will be a foot or so under the water. Then, place a dingy in the water, over the box. Place a mongoose in it, facing the motor. The dingy should sink, with the box there to stop it. Now for opperation. One person drives (duh), and another rides. The rider is there to shoot the dingy whe it starts to sink. Hope I helped