An otherwise ordinary iceberg, weighted with sufficient tonnage of sand/gravel/moraines so it attains neutral buoyancy. Then the addition or removal of air from chambers inside the iceberg could be used to manipulate its submersion depth.
As the ice melts it is a matter of also jettisoning rock into the water, to maintain buoyancy stasis.-- nineteenthly, Jun 01 2011 "Ice" by James Follett http://www.fantasti...mes-follett/ice.htmPrior Art [8th of 7, Jun 01 2011] Heavy water ice http://scienceforum...t-in-regular-water/Same sort of question [Ling, Jun 03 2011] Was this really worth interrupting my attempts to insert Schubert into a Scott Adams cartoon?
Actually, yes, it was. [+]-- pertinax, Jun 01 2011 I couldn't possibly comment.-- nineteenthly, Jun 01 2011 Oh go on, you know you want to.-- 8th of 7, Jun 01 2011 I'll bun it if they're artificial pykrete-burgs instead.-- Mrlemonjelly, Jun 01 2011 You would have to know at what depth the 'enemy submarine' was traveling (if anything fitting that description can be found nowadays) in order to put your modified iceberg into its path, which leads me to two points:
A) almost every method of pinpointing the position of a submarine will make the crew of that submarine aware that you are trying to determine thier position, giving them ample time to react to the iceberg as it heaves into position.
B) since they already know you're looking for them, once you've pinpointed the sub's location there's really no further need for subtlety, so just fire a damn torpedo at them and save the precious pykrete resources for orbital breakfast-food delivery weapons.-- Alterother, Jun 01 2011 "I bet no ship expects to be struck by an iceberg from below."
Nobody expects the Spanish Ice-quisition!-- normzone, Jun 01 2011 <slap>
<link>-- 8th of 7, Jun 01 2011 With some sculpting of the top of the iceberg, this scheme could be used to sneak up on a ship, then jettison ballast and rise beneath it, lifting it out of the water. The (seadragon-shaped) iceberg could then take the helpless ship and its contents home. The music would be from You Only Live Twice and the scene with the spaceship eating rocket. 19thly would be Blofeld (peering from the I of the seadragon Iceberg) but with two ferrets instead of the cat and very buff like the Beastmaster. Yes, yes, it's all coming together...-- bungston, Jun 01 2011 <Quietly removes paper bag containing [bungston]'s remaining supply of Funny Mushrooms>-- 8th of 7, Jun 02 2011 Would heavy water ice be more dense than seawater? Just a thought...-- Ling, Jun 02 2011 Heavy water ice would have a density close to 10/9 that of ordinary ice, or 1.018 g/ml. The density of seawater is about 1.025 g/ml. Very close.-- spidermother, Jun 02 2011 It might not be me looking out from the I.-- nineteenthly, Jun 02 2011 Wouldn't the amount of sand, gravel or whatever ballast necessary to submerge the iceberg make this idea a bit impractical? At least if the iceberg was to have a relevant size to be used as a weapon-- PauloSargaco, Jun 03 2011 Oh, sure, it's the sand/gravel/ballast issue that makes this impractical... and here all this time I thought the impracticality lay in the enourmous surplus of fully-baked anti-submarine technology already sitting around unused because of a noticable reduction in the number of hostile submarines skulking about where they don't belong since the end of the Cold War...-- Alterother, Jun 03 2011 Sand has this habit of melting ice.-- RayfordSteele, Jun 04 2011 random, halfbakery