I have the whole set including mounting hardware if you are interested. I had been saving them to install on the boat that I use to teach from (1307). I have decided that my students will never use them. I even had to remove the tiller extension because it just makes things too complicated for learning. I don't see my teaching boat in competition again.
These were in my ill-fated Knotalot, 477, once a national champion boat. You can see them installed in thethis link and the next few pics http://yourarchivist.com/ensign/boat/slide_06.php
These were tied with super-strong line with holes through the bulkhead and then had metal straps run through loops sewn into the web on the aft end, bolted to the deck just aft of the seats.
I'll let these go for $100, part of which I will donate to our sailing program (as have a other procedes from the sale of my boat parts). email is ksimp@ksimp.org
Keith Simpson, Ex Cm.
Fleet 64, Winnipesaukee, NH
Knotalot 477
Now USSailing Certified Level 1 and Basic Keelboat Instructor
NH Boat Museum/Wolfeboro Parks and Recreation