Submersible movement and mechs

[Burzmali]

In a match I played recently, the map was a flooded city, with most of the surface depth 1 water with patches of depth 2 and 3 water as well as some building and roads to travel on.

One of the mechs had an UMU, and we couldn't determine exactly when and how it was usable. Can a mech with s movement travel on the surface? The table on page 34 AS:CE suggests so, but the rules on pg 36 say that a UMU can only be used while submerged. Per pg 36, would mech in depth 3 water next to shore would be able to exit the water? The best I can figure is that the mech could move to depth 2 via s movement one turn and then exit the water via a 2" height change the next turn with ground movement, but that seems a bit awkward.

I think part of it is that I don't think there is much art of the UMU in action, the one piece I found has the mech in a prone position while using its UMU suggesting that it could be using it at depth 1 without breaking the surface.

[MetalEd]

The way I read it, a mech with UMU can "move as a submarine unit" (pg 35), so would be allowed to be submerged at a depth of 0", i.e. surfaced.  The way I play it, I lay the mech down on its front and use that for how large the unit is, meaning in depth 1" water a mech can either be fully submerged, or, floating on the surface.  And that would allow it to exit depth 3" water from the surface of the water.

If I had to make a TO call, I'd judge that the base of the miniature is what the depth submerged to is, like a VTOL in the air.  This would mean the base could be 'floating' at any depth level the water has, so again a mech could be fully submerged or surfaced, in 1" deep water.  Bonus points awarded if you wiggle your finger in front of your lips while humming to make submarine propeller noises while moving the miniature.

[Paul]

One of the mechs had an UMU, and we couldn't determine exactly when and how it was usable. Can a mech with s movement travel on the surface? The table on page 34 AS:CE suggests so, but the rules on pg 36 say that a UMU can only be used while submerged. Per pg 36, would mech in depth 3 water next to shore would be able to exit the water? The best I can figure is that the mech could move to depth 2 via s movement one turn and then exit the water via a 2" height change the next turn with ground movement, but that seems a bit awkward.

I think part of it is that I don't think there is much art of the UMU in action, the one piece I found has the mech in a prone position while using its UMU suggesting that it could be using it at depth 1 without breaking the surface.

Page 20 of BMM has the answers.

Short:
* mech has to be fully submerged and standing, so Depth 2 or greater
* Can only move between water hexes, so can't be used to transfer between Depth 2 and a Clear Level 0 hex within the same turn (or vice versa)

So your assumption of needing to spread it across 2 turns is correct.