how they do that?

[WayneW]

Yesterday my son and I stripped and sanded that port
side of the hull from the water line doen to the
keel.Once the wood was expose, I could see where
several patches where made on the strip plank hull.
Who ever did the work in the past did a very good
job.It looks like they used a router with a quater
inch wide bit and simple chase the crack.Then they
cut a piece of mahagony and filled the routed
area. The question I have is two-fold - First, how
do you folks think they maintain a straight line with the
router while cutting the grove, and second, how
would you hold the router upside down for such a long time?

[ssor]

You have to be strong enough to hold ten pounds for a few minutes. Second; you nail guide strips along the area that you need to remove and use a pilot bushing in the router base. If your arms get tired you can rest and then go back to work.