Hvor kan jeg kjøper "danksa" undervantsrøstjerner ?

I fancy the idea of setting up my boat so I could row it to safety should the dodgy outboard stop (no wind etc.).
Has anyone tried this? Any tips on how to fasten the rowlocks please.
What about sculling, is that why there is a little hook on top of the rudder?
Thanks

I am thinking of buying a IF. I guess Marieholm made a few small changes to the IF over the years the design was in construction. Can anyone point me to a list of those changes. It would be good to know if there was (if any) differences between a boat built in, say 1973 and a boat built in 1977. man...