[BigWalleye]

Originally Posted by sublynx

Do you use Thomsen's Parameter app? If the game engine treats lifeboats are ships, the app might have changed the displacement of the boats as well.

According to its included help (.chm) file, these are the parameters which can be changed by Thomsen Parameter App:

Engine Power (eng_power), range is 0-100% of original value in the file.
Rudder drag (drag), range is 0.0-0.5. IMPORTANT: THOMSEN PARAMETERS APP determines if the ship is a merchant or a warship by its speed (below 19.5 kts is merchant, above 19.5 kts is warship or liner) and adds automatically an extra 0.01 to the user value when it encounters a ships with a maximum speed above 19.5 kts.
Centre of gravity (gc_height) is 0.0-10.0.
Surface drag (LR), range is 0-0.5.

Displacement is not one of those parameters and, AFAIK, there is no way of using Thomsen Parameter App to change the displacement parameter value in <ship class>.sim.

Also from the .chm:

1. No ship of fewer than 500 tons will have its parameters altered, as originally intended by Thomsen.

Now, I know from testing that the 500-ton limitation refers only to the parameter mass, not displacement. But, IIRC, a non-zero value for mass overrides any value for displacement in either the .sim or .cfg file. So, if the mass parameter value does not exceed 500 tons (and it probably wouldn't for a lifeboat), Thomsen Parameter App will not alter any of the four parameters listed above.

Both the parameters affected and the mass limit could be changed by altering the source code and recompiling. But that would not be done unintentionally.