Land, Air and.....hmm. Something is missing.

[Morgrim]

Imperial skimmers do seem to be smaller, lighter vehicles though, and also rather fragile (although arguably that's a skimmer trait in general). For the specialised "move a large amount of heavy stuff across water" task a skimmer isn't going to cut it. If you're sending in a few hundred guardsmen that's a task for either fliers or watercraft. But agreed that to attack there aren't many options that navy suits best. Perhaps 'towable gun platform'.

[Denzark]

No sure, but you mentioned IG requesting specialist water vehicles. As I said, why use your inter-orbital lift capacity to drop a vehicle onto the sea when it could drop a similar sized vehicle onto the required land mass?

[Katharon]

Did we all forget that there are mechanized regiments of Chimera-mounted guardsmen and women?

[Fueldrop]

Hmmm... some form of amphibious superheavy transport would be fairly awesome.

[grimmas]

If the planet is totally or mostly water then you're going to need some sort of Blue navy, air power is all well and good but to cotrol it you will to get somthing on the surface. Ships are vulnerable to Air power but that's why great efforts are made to protect them, after all one can't bomb a ship is your aircraft is blown out of the sky. The imperium is a big place and not everywhere has vast orbital resources available

[Chris*ta]

Hmmm... some form of amphibious superheavy transport would be fairly awesome.

Isn't the Gorgon amphibious?