In the 6th ed 8.8 does say "In poly-phase motor circuits adequate precautions sould be taken to prevent damage due to single phasing........" but that's about as close as I can get to what you say re the dropped phase.
However if there is no over-heating under normal use then the motor may be over rated for the weight of the armature anyway. Would have to watch it in storm conditions as there's quite a lot of leverage on one of the larger ones in a wind.
If it's only the same fuse blowing then, it may be that the axel is bent and over-stressing the coils at one phase in the rotation.
I'd recommend a swap-out of the motor and shaft unittil so it can be sent back to the manufacturers to be checked. Depends how tight the set-up is financially.............. oh for gods sakes listen to me ....... it's a ship of course there's no money for maintainance