John
There is a dreadful inevitability about answers like this:
I don't know, we havn't got any information to go on.
How long did you get the acceptable performance with the 555 on what battery?
What was the current draw?
What was the ESC rated at before the smoke came out?
what is the KV of a 555. What 555? (it just means a long armature 540 with 5 poles) Did it have a brand name?
Any of those would give us an estimate of the power that gives the kind of performance you like - then selecting a suitable BL is a little more scientific
OR
Find a boat of similar size, mass and performance and copy a successful installation slavishly
What do you intend to do for batteries? - generally gelcells do not appreciate the current draws that BL motors impose (but there are several honourable exceptions)
If you can help with some of these answers I and some people who know will attempt to help
andrew