I have a boat of mark Lomwel.
The yellow one is mine, I find this boat very well built.
These are ready-made boats for 300hp
I do not know the Korteland 21ft was built by Mark Lomwel (but I'm not 100% sure) lots off rumors.
In Holland have been more builders of 21ft Phantoms, some better than others, they are not all of Korteland.
The red Run fo Fun is a one off test boat, with the hook in the bottom.
and mark Lomwel also makes a 21 skater like cat.
Lomwel Outboard Racing