I believe the reasoning is it is more likely to snag on docks and such and be damaged. I've seen it done both ways so it's more a matter of taste. I did not wrap the rail on my Peeler and so far so good.

   I ran my rails past the bow and brought them together. I prefer the appearance over the plan method.  I have had no problems with it.  I suspect the reason the plans have them stop is it requires less carpentry skill as they meet at a compound angle if continued.

I think that dorys were built as work boats, and the rounded bow is less prone to damage, and also allows llines or nets to be dragged from one side to the other over the bow more easily that a pointed bow.  I have a Chesapeake 17 sea kayak with a needle nose.  I'm about midway through shaping my rails at the front, getting ready to turn it over and fiberglass the hull, and am a little worried about that operation.    

As you can see, the rails are rounded at the bow which allows lines to pass easily and gives a protrusion to bump piers, etc. wiothout the leading edge of the boat getting damaged.   Barry

bearnkar, your rail treatment at the bow looks great. I'm just about to glue my rails on my NE Dory and am considering this.

I'd be grateful if you could give some tips on how you did it. I guess I could

1. Glue a rail on one side and then trim it along the axis of the boat's length. 
2. Use that angle as a template to cut the same angle on the other rail and glue it in. 

Otherwise I guess the angles could be measured with a protractor and the rails cut before installation. 

What do you suggest?

Thanks, John

Perhaps: 

http://www.clcboats.com/shoptips/stitch_glue/cutting_bevels.html

Ruud

Thanks Ruud, also if it matters, about my rails: it's just the simple outer rails, I don't have the fancy spacered inwales. They look great but I took a pass as it's my first build. 

   John,  If I recall correctly, I made the rails long and clamped them to the boat then made the cuts. I could then move them forward and adjust the fit as needed. Once that was good, I could finish each at the stern which is an easier fit.

https://www.flickr.com/gp/115824096@N06/59tBJK   

I hope the link to the pictures works. I just clamped and screwed the inner rail on one side and cut it with a Japanese pull saw in line with the middle line of the boat. Repeated on the other side and they fitted pretty well. It does leave a small triangular hole which we've filled with unthickened epoxy to make a little clear window which looks nice. The outer      sections of the rails don't have to be fitted together, just rounded off at the point.

   Peter 99, the leading edge of the bow appears to have a high build of epoxy or is that embedded line?

   No it's epoxy . I didn't have to build it up that much but I preferred the sharper look rather than just rounding it off and exposing some of the interior filler. I hope it's strong enough but it has a layer of glass over it so I think it should be pretty tough