It's needed fo r sailing and rowing, too.

Laszlo

Yeah, Laszlo is right about that (no surprise).  It is hard to keep a boat tracking straight when rowing if it doesn't have a skeg or some sort of hull form aft which accomplishes the same thing.

I had a Sea Pearl 21, motorless most of the 22 seasons we were together, a big boat to row for one oarsman, but is was doable.  Her shape was somewhere between a Swampscot dory and a whaleboat--her narrow bottom was flat right back to the tombstone stern, with no sort of skeg.  She wouldn't row in a straight line for very long until I started putting the kick up rudder about halfway down and lashing the tiller amidships to function as a skeg.  That's a somwhat extreme example, but I think it's applicable here.  (It's worth noting that CLC's Northeast Dory, a very Swampscot-like dory, has a skeg.)

I have a PMD, which I think has an even bigger skeg than your Tenderly, probably because of the boat's much greater bottom rocker and lack of any deadrise aft.  It definitely helps keep her from wandering off course during the recovery if I haven't hit the stroke perfectly evenly if I'm rowing hard.  In fact, if pull with one oar while leaving the other idle on a stroke when I have her moving at speed, she'll briefly go a bit sidewise and then spin right back to about where her momentem wants to carry her--where she was already headed.  Yet, it doesn't really impede her turning her when that is what's wanted.

Also, I find that the skeg help more than it hurts for handling the boat out of the water.  Otherwise, she'd be a total rocking horse.  <;-)

Just my .000098 cents.  "Different ships, different long splices."

.....Michael

   Thanks for the feedback.  Looks like I'll be installing the skeg.

I don't remember that the skeg install on our PMD was particularly difficult, but her flat bottom aft helped that way.  Main thing is to make sure it doesn't go crooked on you.  You'll be fine.

I wish you all joy of your Tenderly!  By all accounts, they bob like a dabbling duck, row like a Canada goose, sail like a watersprite, and carry a load like a...well...I can't think of a burdsome sea creature...like a burro crossing a stream...all that plus being a real head turner for looks!  Right there to hand at your cottage, she'll no doubt get a lot of use, delight your eyes to no end, and I predict that a good time will be had by all.

.....Michael

Canoes used to be built with a sort of keel which were subsequently abandoned. My prospector tracks just fine. Why a skeg on these boats and not on a canoe?

With respect, comparing a (long, narrow) double ender canoe and a (short, wide) dinghy is like comparing oranges and apples. Even your Prospector has some sort of skeg: the rear end acts as it. 

Gramps explanation has it all. If the design has a skeg, install it. 

   Glad you are going with the skeg. Occasionally boat designers know what they are doing.

 ".......  got to thinking that the skeg might possibly get in the way for pulling the boat on shore, or putting it on a trailer. ....."

pulling on shore........just digs a little furrough. It lowers the surface area of stern drag.   It also keeps the rocker in the boat hull from rocking the boat so much on a flat beach. 

putting on a trailer.......isn't that why boat trailers have bunks?