It was the Miss Mel, which (like most Pro-boats) has props, not jet drives. It seems (I am told) that for some reason a pipe containing transmission fluid under pressure let go, spraying the engine room with a fine oil mist. When that reached the turbocharger, the hottest thing in there (the exhaust manifolds are water cooled), it ignited. Probably went up like a bomb, and no automatic extinguisher system (which it didn't have anyway) would have made any difference. It seems possible that just prior to this the oil feed was cut off, giving rise to the reduced oil pressure some divers have reported the crew noticing. This carries an element of surmise as there has been no official report released (and no-one expects one).
Once ignited the fate of the boat will have been sealed, as it was hot enough to melt and ignite the fiberglass. Apparently the fire was so intense that engine parts and scuba cylinders melted together.
Luckily the boat was inside the atoll in calm and shallow (and warm) water not far from the island of Long Caye (where the next dive was to be), so once away from the boat and any possible further explosion no-one was at great risk. Very unfortunate occurrence nonetheless.
Since then, only a couple of days ago, the other big dive boat on the island, AquaDives' 52' boat, is also out of action. In that case it was about to enter the barrier reef on its way back from the Blue Hole when one of the two transmissions failed catastrophically. The boat had to negotiate the reef on just one engine in quite heavy seas, and with greatly reduced control was swept sideways onto a shallow sandbar. No injuries or great drama, but they can't drag the boat off as there's coral in the way, so they're waiting for a crane to lift it. No hull damage but quite a lot to props and one shaft. Again, most unfortunate and (at the time) unavoidable. No blame can possibly attach to the owner/operator.
A few weeks ago another boat ran onto coral when trying to negotiate shallow water in a sudden storm. As I said on an earlier post, the sea's always in charge.
