I saw after I posted for your post that this thread is 6 yrs old. Probably not much more from the OP’s is gonna come out.
IOM, Noux by Anders Wallin: http://www.anderswallin.net/2006/03/noux-2-layout-plan-and-3d-iges-file/
IOM, Laerke by Soren Anderson: http://www.anderswallin.net/2004/11/laerke-iom-by-søren-andresen/
Other IOM plans and component design as well on Anderswallin.net
I have also posted the plans from the Velarc.it website of the VO-70 boats, ABN Amro 1 and 2, Illbruck and Erricsson at a file sharing site, http://www.filefactory.com/f/6e01e30cc7e3300b/ These plans, copyright by Francesco Bussi, 2005, francescobussi@yahoo.it are not to be used for any commercial purpose, but free license is granted for personal use.
Another site with LOTS of free plans, RG65, IOM 10Rater, and a few others:
http://www.velarc.net/plantas_eng.htm
The IOM, Maximus MK2: http://smys.yolasite.com/plans.php