NiMH batteries and R/C models.

When I was a child I had 2 model boats which used an oblong pack of 6 not-quite C sized NiCad cells, 7.2 volts, and about 1200mA or so.

I have dug them out with a view to entertaining the nephews. The NiCads went years ago.

One boat has a 540 sized motor (just a "normal" one, not a more powerful competition tuned one), and the other has a "normal" 380 sized motor.

As they are boats, and space isn't at a premium, is there any reason not to:

1. Use common C sized NiMH cells in their place?

1. Use common AA sized NiMH cells?

Both would offer an increase in capacity, and in the case of the AA cells, are cheaply available from IKEA.

Thanks in advance.