Hi Bob,
Swampgirl isn't a hard boat to build. Just stick to Matts drawings and build instructions and you shouldn't have any real problems.
I had several problems with my build and I am now fairly confident that I know what I did wrong.
1. I used heavier, hardwood bracing ply on the bottom panels combined with very light, thin, soft wood ply for the sides. the difference in strength and bend charactistics meant that my thin sides were not strong enough to force the bottom panels to conform to the designed bottom shape near the ends.
2. Most importantly, I DIDN'T FOLLOW MATT'S BUILD INSTRUCTIONS.
Even with the glaring mistakes I made, my swampgirl still performed beautifully for what she is, a skinny water boat. With the sides at the designed height, she would take a reasonable chop easily and is stable enough to stand in if you want. This may take some practice.
To give an idea of the extent of the mistakes I made, look at the piccie below. This was my swampgirl during build. if you look at the keel line of her from about where the blue deck of the kayak behind dissappeards behind the swamp girl, you will se a marked dip, This should not be there.
Also, where the bottom panel meets the next side panel, in about the same place. See the wavy join line? That also should not be like that. The lines, curves and panel joints should flow neatly into each other and over the length of the boat. This is not difficult to achieve. I was in just too much of a hurry to get her built to take proper care and check my work..
If you are planning to paddle skinny water, either boat will fit your needs well. What-ever boat you finally decide on, I would reccommend the pirogue as a first build, simply because it is easier in that there are less panels. There is a definate learning curve to this caper, especially in the filleting and fibreglassing the inside.
Good luck mate and please keep us posted.