Monday 21 August 2023

Fitting Out | Tabernacle & Mast

With the mast complete and ready to go onto the boat I now needed to make sure that it fitted into the tabernacle.

So I made a test fit with the mast horizontal and the tabernacle dropped onto it, like this.

Two problems were immediately apparent.

The pivot bolt did not slide through the mast and out the other side of the tabernacle, and the mast could not be lowered sufficiently because the rear face of the tabernacle was too high.

I expected to ream out the pivot holes to get a good fit but I was very surprised to find that the tabernacle was wrong.

I checked the tabernacle against the pattern for the rear face, and it was exactly as specified. Like this.

So the pattern is the wrong height. Annoying, but not the end of the world. All I had to do was remove a piece at the top of the rear wall.

Some time ago I bought a multi purpose tool after seeing a plumber cut a neat square hole in our ceiling with just such a tool, to fix a leak.

If I had known that such a thing existed I could have used one to remove the floorboard cleat on bulkhead two which turned out to be 1/2" too high. As it was I went to enormous trouble to modify the floorboards and the cleat to resolve the problem.

So when I saw a tool which could make neat vertical plunge cuts I bought one, knowing that I would have a similar problem again at some point in the build.

This was it.

Here is the tool kit which I deployed.

I marked up 1/2" to be removed from the rear wall, and used the large Japanese pull saw to make the vertical cuts.

Then I used the multi purpose tool to slice out the waste, and a chisel and sandpaper to clean up.

This is what it now looked like.

That will look fine when touched up.

Another test fit followed. The problem had been solved, as here.

There is now good clearance for the mast to be fully lowered.

I used a 10mm rod in the mast and in the tabernacle to find how badly the pivot holes were misaligned, using the engineer's square to measure it. Like this.

You can see that the hole through the tabernacle is not perpendicular.

A similar check on the mast showed the same thing, but in the opposite direction. No wonder the pivot did not fit!

I marked up the diverging pivot holes to show what was happening. This is it.

The hole through the mast slants to the left, and the hole in the tabernacle goes to the right. The pencil lines are indicative - not actual angles.

Not out by much but together making it impossible to fit the pivot bolt.

The problem was quickly solved by reaming out each hole on the appropriate side so that they aligned properly.

The pivot bolt was now in place and the mast fully lowered, as in this pic.

Time to fit the boom gooseneck to the tabernacle.

The manual says that it is through bolted to the rear face, but I did not see how that was possible because the mast lies flat against it when raised.

Except it doesn't, does it? The manual also tells us to place a small block of wood on top of the bowsprit inside the tabernacle, 18mm thick. This is to dial in a small amount of mast rake, to make PocketShip sail better.

Hmmmm. Would that allow enough room inside the tabernacle to allow through fastening?

I found a bottle top that was 18mm tall and stuck it in the tabernacle, where the block of wood would go. Then I again simulated raising the mast, like this.

Plenty of daylight in there! This is what it  looked like at the top, with the 18mm cap in place.

There seemed to be plenty of room for fastenings, so I went ahead with this approach.

Here I have marked up for the gooseneck, as specified by the manual.

And this is the gooseneck in place after final fit with sealant.

While I was at it I made a block of Ash to fit inside the tabernacle. Here it is.

And here it is inside the tabernacle.

I think that's the tabernacle finished.

I can't complete fitting out (spinnaker sheet cleats, chainplates, mainsheet blocks) until the boat is moved outside onto its trailer and the mast installed.

So now I need to organise that momentous event!

No comments:

Post a Comment