Skin thickness subtraction in Freeship/Delftship

Just wondering if anyone knows of or has looked at writing a plugin that will correctly handle skin thickness subtraction?

I'm aware that the apps were written primarily for large commercial vessels in which this is not important, but given the popularity of this software for smaller vessels it seems to me there would be a lot of people wanting such a plugin.

Unfortunately I'm not capable of writing one since I know nothing about Delphi. I did once write such a routine for a Hewlett-Packard programmable calculator way back in the Paleolithic (yes, it worked fine) but something more spiffy would be great, and preferably without installing half a dozen apps to do one job.