The Naiad Voyages

Mark Austen

2016.05.30 - Sticky Ribs

I spent the evenings of last week in the workshop but not working on Naiad, alas. Instead I build two Glastonbury Chairs that needed to be ready for the Bank Holiday Weekend. But today I carried on with the rib work by glueing in the aft most pair. The position of these two is a lot more critical than the others, in fact it doesn't really matter where the others go as long as they are the same both sides, but the aft-most pair of ribs are coincident with the back of the cabin so have to be correct. The photos below show the workings.

Two marks were made on a long pole, one 66" and the other 64 1/4" from the end. The pole was laid in the hull with the end against the transom and a mark made on the centreboard case against the shorter mark on the pole.


The pole was then played on the transom as shown.


You can see here that the line on the centreboard case and the longer of the two marks on the pole are in the same place.


The cross line laser level was turned on and the hull moved around and things adjusted until the red line across the hull went through the one on the pole and the line on the centreboard case ensuring that the laser was now in the correct position. You can also see the fore-and-aft line along the case as well.


A soft pencil was used to mark the position of the laser line across the hull making sure that my weight in the hull did not disturb the alignment of everything.


The line on the paint work showed where I needed to sand off the paint to allow the epoxy to be applied to the wooden surface.


Thickened epoxy was applied to the lower surface the rib and then eased into position. The upper end was lightly clamped and then I stood on the near horizontal part of the rib to push it hard against the hull and tightened up the clamp to hold it in place. A chunk of lead was rested on the inboard end where it is not possible to use a clamp.


The epoxy, position lightly clamp, stand on rib, tighten clamp and place lead on the rib was repeated for the other side.


A view from the stern showing both ribs. I was tempted to do the next set of ribs, but I was fairly sure that if I did I would soon regret it as the aft-most set of rib are pretty much where I climb in to the hull and I was bound to dislodge one rib or the other.