The seatback blocking was all installed, levelled and flattened. The next step was to make sure the stern blocking was ready for the boom gallows stanchions, which are 25mm stainless steel and will require very strong support blocks.
First, we have to bore a 25mm hole through the blocking at the stern of the boat. The exact position of this hole is not obvious in the build manual or the drawings, so I decided where it would go myself.
I marked in the centre of the hole 11.5cm from the transom skirt. This looks about right.
I used my UJK drill guide to bore perfectly perpendicular holes. I purchased this last year with just this sort of task in mind.
It is very difficult to drill a perfectly vertical hole by hand, and it is impossible to make large holes in this way.
But with a really good drill guide it is achievable.
First I set up the drill guide on the port seatback, fitted with a 25mm Forstner bit. Here it is.
I did the set up without the drill fitted, so that it was easier to manoeuvre. The base plate is secured to the blocking with a woodscrew, to hold it in place.
And here it is in place on the starboard side, with the drill fitted.
I used a level across the base plate to make sure it was level, like this.
Boring the holes was straightforward, but I think I will try the small corded Bosch drill next time.
This cordless DeWalt drill is very big and makes the drill guide top heavy and a bit hard to handle.
My small Bosch cordless drill isn't powerful enough for this, but I think its corded counterpart would be. We will have a test run at some point.
Anyway, I successfully drilled both holes port and starboard. They are very clean cut and perfectly perpendicular.
Here is the hole in the port seatback.
The next task is to install some sort of block on the floor of the seatback locker to receive the bottom end of the stanchion. That looked like it might be quite 'challenging'!