The Naiad Voyages

Mark Austen

2015.11.08 - A Good Weekend

It has been a Good Weekend for the Naiad Project for a number of reason, despite being more than a tad under the weather and therefore feeling pretty awful.

The first reason can be seen in the image to the right, the inner veneer on the starboard side is now in place and all the staples are removed. I decided against sanding the veneer at this point as that would remove wood and therefore some of the strength. Also, when the boat is turned over and the first veneer glued in from the outside, epoxy will find its way through any gaps between the veneers. This is a good thing and in fact I will make sure that it does by forcing epoxy in to any spaces between the veneers that I can see. Once the boat is righted this, by then, hardened epoxy will have to be sanded flush with the inner veneer and I hate doing something twice. So I’ll leave it until the repair is completed on that side.

Another reason that is has been a Good Weekend is that I was not only able to make a start on the removal of the port thwart, but I was able to complete it. The entire removal process took only a couple of hours instead of a couple of days. This is entirely due to knowing how the starboard thwart was constructed and thus knowing what I had to do to get the port thwart removed. You can see the progress of that process in the photos below.

Yet another reason for the Good Weekend is that although there is some rot on the port side, it is not as extensive as the rot on the starboard side and it is most certainly rot. Having cleared out the majority of the foam, I used a crowbar to scrape against the inner veneer to check for soft areas and as soon as the damaged wood lifted away I could smell the dreaded rot. Most wooden boat sailors know what I’m talking about, it fills our nightmares. And, unlike the starboard side, the wood was damp.

And another reason for the Good Weekend is that the rot as far as I can tell, has only damaged the inner veneer, there is no sign of it having penetrated the glue line and into the second veneer. I still have to remove the thwart and bilge stringers to allow me to check the complete extent of the rot but I was somewhat rough with the end of the crowbar and had there been any penetration of the second veneer I probably would have found it.

And yet another reason for the Good Weekend is that because the damage only seems to be the inner veneer, I do not have to do any more than cut out the bad veneer and replace that one layer.

Finally, for now, a reason for the Good Weekend is that this means that my target of having Naiad ready for the rebuild by the end of 2015 is now achievable.

So why is there rot on the inside of a sealed buoyancy chamber? The answer, I think, lies with the foam. The chamber itself was very well and stoutly constructed and there are no obvious places where water could have found its way in.

Twenty-five years ago the wooden boat magazines were full of praise for expanding foam for buoyancy as I recall. The trouble is that when it is expanding the foam exerts a huge pressure on the chamber. On the starboard side I found that the foam had forced its way between the thwart stringer and the hull leaving a route for the water to enter. I fully expect to find the same thing on the port side in the area above the rot.

This would have allowed water in very slowly over 25 years but eventually there was enough for rot to grow. You cannot see the problem from the outside, there is no obvious crack in the paint but it is there nevertheless. Or it was on the starboard side.

The moral of this story is never to make sealed chambers on a wooden boat. All areas of the hull should be ventilated so that any water that does get in can evaporate or have at least one drain hole so that water cannot get trapped.

So, here is the port thwart ready for me to cut it out.


Using the reciprocating saw I have cut around the edges of the thwart.


Another view of the cut.


Although you cannot see it at this point, the hacksaw blade on the thwart has been used to cut the foam inside the thwart by sliding it into the slot and sawing the foam through as far as the hull.


A crowbar is a useful thing but you have to use it with care. In this case I had to be careful not to damage the hull.


Easy does it.


Now you can see the entire cut out area being lifted away from the hull.


Another view of the previous photo.


The thwart now removed. An easy job compared to the other side.


The black coating on the interior of the buoyancy chambers is a rubberoid compound and amazingly the area in the centre of this photo shows one bit of the compound that was still tacky. I could smell the solvent when I cleaned it up just here, 25 years after it was originally applied.


And so on to the rot. This is the extent of the damage after I have used the crowbar to scrape at the wood. Considerably less than the other side.


Another view of the port side damage.