Ama (?)

We spent the weekend in the mountains, in the presence of good friends and a lot of tempting timber.  Finally, when I found a downed aspen trunk that looked straight enough and about the right size for the ama (outrigger), I couldn't take it any longer.  I asked our hosts if they would mind me taking the tree, and they gave their permission enthusiastically when they heard what I wanted it for.  Turns out they'd given permission for a relative to fell the trees for a project, but he got a job out of town before he could use them, and they'd been languishing since.

So I now have a 13' aspen log on my dining room table. 

I've stripped the bark off of it, and it's firm wood with no rot damage.  I've also taken from the plans some rough "by eye" guides for the shape of the finished ama's cross-section at certain points:

However, there's one small problem, and it has cropped up every single time I've dealt with found timber: It never turns out as perfect as you thought it would.  It's always a little crooked, or a little too short, or something. 

In this case, the aspen trunk is a bit crooked, but acceptably so.  The real issue is that none of what I brought home quite reaches the 4.75" diameter recommended in the plans.  The fat end is a little too skinny:

A 4.75" circle leaves gaps all around at the
fattest part of my ama candidate.  Is this okay?

and it just gets skinnier from there, down to around 3.00" diameter at the skinny end.  So there's a real chance that this ama won't provide enough flotation when it's on the leeward side, or enough weight when it's on the windward side.

On the other hand, it's aspen, so it's light and strong.  And it's by far the closest thing I've found so far, unless you count the two-piece aspen trunk offered to me by a friend.  And having stared at a fair number of tree trunks now, I have to say I'm not sure I can find anything else this straight.

As for whether it's too light.... outrigger guru Gary Dierking has instructions for a foam and fiberglass ama on his website, so flotation must matter more than weight.  Flotation is a product of size and density; this ama is a bit small, but it's also at the low end of the recommended density range, so it might work out after all.

So my plan is to set it aside, maybe work a little on shaping it when I have free time, but not to invest too much in this piece until I decide it's my best option.  When I'm done with the hull, I'll shape an ama out of the best piece of wood I have at that point.  If initial sea trials are disappointing, I might even try Gary's foam & glass option.