I just opened the shipping boxes on an Eastport Pram yesterday Humphrey. Wish I had an answer for you. When you get an answer (to your mast step question), please post it... I'll be interested! 8-11-23 

When the boat is properly positioned, the front seat is level. In the picture below, the builder is using a combination square to position the mast step (use your browser's zoom feature to see it better). The spirit level will indicate level when the boat is in the proper position and then the rule will indicate where the step needs to be.

This picture is from the construction gallery, accessible from the Eastport Pram page. The pictures in the gallery are a big help in answering build questions.

Have fun,

Laszlo

Interesting question. I'd try to get the boat on the sawhorses so that it looks the way you expect it to look when it sits in the water. Prop the bow or stern as needed. The point of positioning the mast step perpendicularly under the doubler is to make sure that you do not cant the mast too far forward or aft -- either of which will affect sailing performance. 

So if the boat is sitting level (to your eye) and you tentatively position the mast step using the technique Laszlo recommends, you can then "check your work" by having a helper hold a long, light piece of wood (say a 10' 2"x2") in the slots as if it is a mast. Look carefully at it from as much distance as you can manage and from every angle. If it doesn't look raked fore or aft, I think you'll be just fine.  

   Thanks Laszlo - knowing that the front seat is supposed to be level is exactly what I needed! Using the bottom scarf of the mast itself as the perpendicylar, it might as well get used to where it's supposed to be :)