Sad as it may seem, I was thinking about this in the early hours of this morning.
Think of the boat as a 7 metre plank of (very strong non-bendy) material with a mass of 1500kg. Put a triangular piece of wood under each end. I agree that the weight would be evenly shared, with a force of 750NM at each end.
If we then add a load of 500kg directly over one of the supports, the force on this support would increase to 1250NM, whereas it would not affect the other end, which would still be subjected to 750NM. Not unlike a boat + outboard?
Of course, most outboards hang off the back of the transom, rather like moving the corresponding support in a bit. What happens now? Answer: the load on the furthest support is offset by the outboard trying to force the other end down. Put another way, the load on the forward support gets lighter! As you will appreciate, the force on lifting points will be upwards in the same way as the lumps of wood, so they both act as pivots.
I would therefore submit that, in your example, the load on the transom is likely to be somewhat greater than 1 ton, unless there is a very substantial amount of fuel, acting as a counter-balance, with significantly less load on the bow lifting point. I do, however, agree with your comments about pressure being force divided by surface area through which it acts.
Sorry if this is a bit "heavy", if you'll pardon the pun.