Position of mast in small skiff

[BrianY]

I've found advice here and elsewhere on how to increase the length of a small boat design - basically increasing station spacing by a modest amount is O.K., increasing beam is not - but what do you do about the position of the mast and centerboard in a sailing skiff? For example, let's say I have a 12 foot sailing skiff that I want to lengthen to 14 feet. I can increase the distance between the four stations by 6 inches to get the required length, but where do I put the mast and centerboard? Do I more these aft by 6 inches too?

[Steve Lansdowne]

It is good you're thinking about this now rather than later. I didn't when I stretched a sailing canoe and had some problems. Read my comments and then search the Forum or wait for more comments before you make any decisions. I'm no expert here but do have some knowledge.

The center of effort of your sail should be in a certain relative position to (either even with or slightly abaft) the hull's center of lateral plane ("hull pivot point"), which is a function of the centerboard location, in order to have weather helm (that is, to keep the bow pointed into the wind if you fall off and thus keep the boat from sailing off without you). You need to take this into account when planning where things go. You're stretching the boat but not the sail, I presume, so if you put the mast proportionally where it should be and not take into account the centerboard's location relative to this point you'd likely have the sail too far forward. On the other hand, moving the sail aft to be in the correct position with regard to the centerboard would, I believe, change the boat's sailing characteristics. This is where somebody with more knowledge than I will, I trust, add some comments that will tell you how to address this, if in fact it can be addressed in words rather than a more detailed analysis than can be given via the Forum.