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Annie Hill

Annie Hill
Photo credit: Alvah Simon

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About Me

25 June, 2017

The Tabernacle, plus DIY composting toilet

Early in the piece, I decided that I wanted a tabernacle and David supported this idea.  The obvious reason for putting a junk mast in a tabernacle is that you can raise and lower it without the need for a crane: when the mast is stepped on the keel, getting it in or out is otherwise quite an issue.  It's not just a case of undoing the clasp and giving it a shove backwards, but if you position the boat securely - and in SibLim's case, firmly aground would be the secure spot of choice - and then find a suitable strong point, fairly high up, you can use a rope from the mast head to take the weight and lower it under some form of control.  For all that, it's not something I'm likely to undertake lightly.  However, there were - for me - two additional reasons for wanting a tabernacle.  The first is that a mast that goes through the deck can leak.  It doesn't have to, and indeed, it's rarely been an issue for me, but it can do and when it does it's very unpleasant with the likelihood of getting saltwater on my feather quilt - something that is frankly intolerable.  An unstayed mast needs to be keel stepped, but if you bury it firmly in a tabernacle that is keel stepped, you achieve the same ends, but as the tabernacle will never have to come out, it can be glued in at deck level and won't leak.  Point number one.  Point number two is that as I can't afford either the cost or the weight of a wooden mast, SibLim's mast will be made like Fantail's, with an alloy lower mast and a wooden upper one.  I don't like alloy: it's cold and unattractive.  However, the tabernacle could be build out of wood - indeed that would be the easiest way to build it and a nicely varnished tabernacle would be a thing of beauty in my forecabin.  And so it was decided.  That Pete should offer to come along and make me one was the icing on the cake.

BBS Timbers are a pleasure to deal with, there's no doubt about it and their wood is first-class.  I bought the Douglas fir for the topmast from them and it's some of the best I've ever seen.  However, it cost me the best part of a thousand dollars and I didn't think I could afford possibly even more for my tabernacle.  Pete had recently build a topmast for another junkie, here in NZ and had bought some beautiful demolition Douglas fir from St Lukes Timber - a timber yard just outside Auckland, so I went down there one day, and bought two big 2 large beams, each 200 x 150 and brought them back to Whangarei.  They were still eye-wateringly expensive, but about a quarter of what the timber would have cost new.

Pete came along to build the tabernacle just after the JRA AGM, in early April, and an Ozzie junkie, Dieter, came along to join in the fun.  Between them they milled the timber to suitable dimensions and then Pete got to work.  The two large beams were machined into 50mm boards for the tabernacle. There were two, almost knot-free boards which Pete selected for the two long timbers that would go from the keel, through the deck and up another metre to form the sides of the tabernacle.

I have fond memories of the tabernacle that we fitted on Missee Lee, and ever the nostalgia junkie, was hoping to reproduce the effect on SibLim.  Pete and I were delighted - and somewhat surprised - to see we could get the large boards of Douglas fir to bend to a pleasing taper, which will look much more attractive than a straight, solid section.

At deck level there is a laminated block, which provides support at the base of the mast and incidentally stiffens the deck at this point.  We made it of a couple of pieces, with the upper part of kwila, left over from the skegs, which is nice and hard in case the mast does move and chafe a little.

Because the tube is round, we had to make the tabernacle to support this.  We machined some triangular section pieces of Douglas fir and glued these into the corners of the tabernacle to support the mast.  Here I am precoating the sides before gluing the chocks on.

And here are the wedges, ready to be glued into place.

The wedges weren't the easiest of things to clamp into place.  It's times like this when I really appreciate the fact that epoxy really only needs to make good contact between the gluing surfaces, and doesn't require pressure.

Pete shaping the top of the tabernacle where the hinge system (yet to be designed) will fit.  The logical way to hinge the mast would be to put a damn great bolt through it and pivot on that.  However, this would seriously weaken the alloy tube and it wouldn't actually do much for the tabernacle.  The idea is to attach something to the back of the mast - like a tube - in some way use this for pivoting around.  This would be a lot easier with a wooden base, but for the moment the design is 'on hold' while I wait for inspiration to strike.  It's not exactly a priority at the moment!

The lower part of the tabernacle can be left partly open, fore and aft for the sake of aesthetics, because it takes very little load. The fill-in piece is curved to spread loads evenly where it ends.  It's not necessary to take it right down to the keel and completely unnecessary to have timber down the front of the tabernacle.  I debated fitting little shelves across, on which to display objets d'art, but as you would have to sit at the forward end of the bunk to admire them, decided it probably wasn't worth it.  But it would have been a nice little touch.

Douglas fir was laminated into blocking for the base of the tabernacle.  This is where it will sit in what is effectively a mast step and because the loads from the mast will be transferred down the tabernacle to this point, it needs to be substantial.  From pure and personal observation, the partners don't seem to take a vast amount of load - but the foot does.


The main pieces laid out ready to assemble. Above decks, everything is covered in bi-axial glass cloth and epoxy. I hate using bi-axial - it's impossible to wet it out invisibly, which I take a pride in doing.  But it does add strength to the job.  However, as bi-axial fibreglass goes, it went on OK.

Once the epoxy had cured, I sanded everything down and then the back of the tabernacle was screwed and glued to the sides.  While the glue was setting up. we added a couple of clamps just to ensure that it all stayed square.  It's now starting to look something like and those who had been coming to watch now had expressions of slowly-dawning illumination when they looked at it.  Tabernacles for free-standing masts are not really 'intuitive'.

We'd used pretty massive screws to hold  everything together and these required a plugging.  My puny little cutters came nowhere near the job, but fortunately Noel, the Whangarei boatbuilder who works at Norsand has everything in one or other of his numerous tool boxes.  He generously lent me what was required and I spent a happy time, standing in the corner cutting plugs from scrap Douglas fir.

Here you can see the blocking at the base of the mast, and also get a good idea of the nice quality of the fir.

These are some of the screws that had to be plugged.  Most of the time, I remove fastenings when I'm building.  They add cost (and weight!), but they can also make it difficult to do repairs.  However, when you get to such large timbers, you are asking a lot of the glue, so a couple of additional fastenings does add reassurance.

All the inside of the tabernacle, where the mast will be, is covered in glass and epoxy and then coated again. It will all be painted in due course, above decks.  

Below decks, the glass stops and the tabernacle is just coated in several coats of clear epoxy.  This will be varnished, and so I have a 'wooden mast' below rather than an alloy one.  You can see the cut-off point quite clearly here: in spite of my best efforts, the bi-axial glass looks slightly milky due to entrapped air.

Needless to say, we could hardly wait to offer it up and see what it looks like.  It's both long and heavy and it was a bit of a struggle to get it into place without knocking bits off anything.  Pete, in the forward cabin, gives some idea of scale. The yellow batten more or less delineates the line of the deck.  In all honestly, I have to say that it looks pretty massive!  And yes, it is off-centre.  This is to allow for a bigger bunk and means that the sail will end up on the centre line.  Putting masts on the centreline is an occidental obsession.  In the days when the Chinese built large, ocean going junks, they used to scatter the masts around with gay abandon, apparently wherever there was an unused spot.

This photograph is what the tabernacle will look like when sitting up in the bunk.  Thankfully, it is somewhat less dominating.  In fact, I find it very pleasing and a lot more attractive than the alloy tube I had next to my pillow on Fantail.  We took it out again after the trial: I need to make a step to hold it in place, first.

As I mentioned in the previous post, before doing this, I had first to establish exactly how far it was from keel to deck and to do this I had to fit deck beams to work out where the deck was to go.  

By the end of May, I had built up the sheer clamp, ready to plane to shape and notch for the deck beams.  However, it is difficult to get at, and my friend and landlord, Marcus, promised to make me a staging to work from.  This has proven to be a bit easier said that done as he has been otherwise occupied in the Bay of Islands.  However - there is no shortage of work on a boat in build.

I carried on in the forecabin.  I've been giving a bit of thought to insulation.  I don't see my taking SibLim into icy waters, but it can get a bit nippy here in NZ and as well as a wood stove for heat, I will need to consider condensation.  However too much insulation makes for a cold boat in spring and autumn mornings.  So I've decided just to insulate alongside the bunk and have an air gap in the deckhead.  

 Marcus had some insulation material kicking around and offered me some, which I stuck to the side of the boat.  I then made a plywood panel to cover the insulation alongside the bunk and the little chocks are to glue it to.

As usual, I pre-coated the back.  I'd had notions of being able to staple it to the blocking, but even after giving the insulation a trim so that it didn't require compressing, I discovered that there was simply too much curve in the hull here.  So it was back to drilling holes, backing out screws and filling again.

After doing this, I decided to do a bit more preparation work for painting, so that I can get the job done as I go along.  Otherwise it will be an enormous effort at the end of the build.  So I've been coating and filleting along chine logs and stringers, sanding and filling, filling and sanding.  I can hardly go for a 'super-yacht' finish - nor would I if I could - but I'm after something that is neat and workmanlike.
 Alongside the bilgeboards, on deck, are two lockers, which I may well use for firewood.  They should be relatively dry and because they are isolated from the rest of the boat, I will be able to bring wood aboard from ashore, without worrying too much about dirt and insects.  As I walk past them every day, I decided to get some paint inside them.  I also drilled a couple of drainage holes for the inevitable rain water that will find its way in.

This seems like a good time to start on the heads comparment, too.  I have decided on the jerricans that I'm using for my water supplies and flopped down a floorboard to check that they would fit under OK.  No problems.  However, I'm fitting a composting toilet and need to be sure that I have room for a hatch for these jerricans, between it and the bulkhead.
The passage way is offset, but pretty wide.  The original plan was to have the head facing inboard, but perching myself there on a handy bucket felt distinctly precarious.  I'd much rather have the toilet fore and aft with a wee bulkhead to support me.  But that would mean I'd have to shift my planned battery stowage.  Time spent with a tape measure appears to show that this idea will work, but seeing as how I was thinking about, I decided to go ahead and make a composting heads.

I had had a C-head on Fantail and loved it.  But it hadn't been cheap and the wee bottle was a bit too wee for my requirements.  Churning the compost doesn't seem essential, so I decided to try making my own, without.

Accepting having the locally-owned DIY store's logo on the 20 litre bucket saved me $13 and there is no shortage (I regret to say) of disposable water bottles about, so I scavenged one from the skip.  The trickiest part of a composter is keeping the liquids and solids separated, and I decided to invest in an off-the-shelf urine diverter from Kildwick low impact toilets

in the UK.  Infuriatingly, I found a cheaper one at We pee, but I also found plans to make a toilet at the same site.  It's hardly rocket science, but a set of plans does point out such things as making sure the back of the seat is square.  I decided to make my seat, too, out of Tiger wood (Marcus and I bought a load from BBS).
Here is the seat itself, placed on the lid, ready for marking.  You make the hole in the plywood a bit bigger and then secure the seat to it.  Apparently, the thinking appears to be that you ventilate the box, but you don't let air in or out around the seat and lid.  I gather this reduces insect issues too, not that I had any with the C-head.  Behind you can see the plywood cut to size.  The heads bulkhead will form the back and the sole will form the bottom, with everything filleted together, to make it easy to keep clean.  When I tried it all out, I found it was far too high.  I need the height if I continue to use the 6 litre water bottle, but 5 litres should be adequate, so I've decided to cut it down 50mm and see what I can find.  If all else fails, I can buy this from the Little House Company.

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