OAP, the Navy would have used Mk 10 IIRC which I think were fused on the side compared with RAF Mk 11 or 12, which both had N&T. One was cast and the other forged. I would guess cast iron was better for that job.
Regarding Napalm, I can confirm the RAF did not use Napalm. Instead they would have used liquefied petroleum jelly (I think it was called)
