Sunday, November 10, 2019

We went sailing last weekend.

Its springtime here, the temperatures at night are still a bit chilly, especially up on the mountain lakes but the daytimes are lovely.  We had great weather, the sailing ranged from drifting conditions to really gusty, and as often the case on a lake with high hills and mountains around, the wind can vary in strength and direction in seconds. Challenging but fun.

Lake Tarawera is a volcanic lake roughly in the middle of our North Island, the result of a depression along a major geological fault line, has many hot spots, streams that run anything from lukewarm to hot enough to cook food in. Mt Doom, that’s mount Tarawera last erupted in 1886  which in vulcanology terms is very recent and the area is rated as “active”.

The lake is lovely, its in hilly country and is surrounded for the most part by forest,  the few houses are along a short str
ip of coast on the north side, and there are a number of well set up boat ramps and carparks which make launching and hauling our boats out easy and convenient.

Last weekend a group of us met there, sailed, camped, some tenting ashore and some sleeping on board.  We soaked in hot pools, swam in the lake, walked the bush tracks and otherwise just hung out with friends.
It was a great weekend, I’m planning to go back sometime soon.

For lots of pics, check out the Dinghy Cruising NZ facebook page, it’s a public page so you don’t have to sign up to view it.

In the meantime, here’s a pic of me out in Spook, her new mainsail setting nicely, it’s a little bigger than her old one, and that was a mighty big sail, but Spook carries the new one well. Thanks Dennis Conway for all the effort that went into designing and making it.

Sunday, October 20, 2019

I get questions about making a hollow mast, so here's how I go about it.

Mast making. Reinforcing an aluminium tube spar with a birdmouth inner plus solid blocking.

I’ve been given a mast blank,  a 5m long x 75, od, 5mm wall thickness chunk of T6 temper aluminium tube.  It was bought to be the main mast for a Pathfinder, but life got in the way of the builder completing the project and he very generously donated it to my cause.  (Thanks so much Brian,  very much appreciated)

It’s a little light for the unstayed rig on the longer, but slimmer, water ballasted Long Steps, so I’m reinforcing it through the mast step area and up to where the boom of the balanced lug main will be by making a hollow wooden tube that is a close fit inside, that takes care of the worst of the bending stresses where it passes through the top step in the roof of the “cabin”.
Its also a little bit short, so I need to make a wooden plug  to extend the top end of it, and while at it will put a tapered section on to get the halyard well above the yard and to fly the wind direction arrow up out of the turbulence of the mainsail.
Besides, it looks nice.

There has been a little discussion on my facebook group about birdsmouth spars, so, here’s an opportunity to show a step by step “how to”.

The reinforcing plug at the lower end is 1600 mm long, sized to fit inside the aly tube, and 250mm of it extends out the lower end to help give the spar a bit more length.  That section needs to be the same diameter as the outside of the aly tube, 75mm instead of the inside being 65mm.

Step one, off to Duckworksmagazine archives, and look up the birdsmouth spar calculator,

I wanted to have some spare thickness, especially in the lower piece so where I’d brought the diameter down to the ID of the aly tube, I’d still have enough to make a good contribution to the stiffness of the spar through that area, so went for a stave thickness of 22mm, that for the top and the bottom pieces.
It coincided with the thickness of a stack of planks I had, as with the length, they were pretty much made for the job at 140 x 22mm x 1600 long, or should I say the job was made for the materials available at the time.

I use 8 sides in most of my birdsmouth spars, I’ve a very good sawbench, (MBS 250, 3 hp,  good machine, often have other brands names on them) so I design my work around that.
Staves were 32mm x 22 mm, with a 45/45 deg vee in one edge, and that, with 16 staves took me a while to first straighten one of the rough sawn edges, poke the planks through the planer, then the other side to get them to the correct thickness then back to the sawbench to rip the planks into staves at the required width.

Next, set the saw blade over at 45 deg, run some scrap to get the blade height and the fence set right, and slide the staves through, one side, then swap ends and do the other side.  Nice little triangular pieces of waste and a lot of sawdust.

Some people will run these vee shapes with a router in a table, but as you can see, a sawbench with a good fence and a sharp blade does a perfectly adequate job, and much quicker.

Once done, being that these planks had been outside under very indifferent cover for two years, I stacked them with fillets ( stickers in US terminology) between the layers to help air circulation and left them for a week to get rid of excess moisture.
I don’t know for sure, but I think that these planks are American Southern Yellow Pine, they arrived here in NZ disguised as a shipping pallet. I was pleased to have them.  ( Thanks Bill)  The wood is fairly light weight, but tough and strong, glues well, is a bit tetchy to plane if you hit a knot or some reverse grain, but a very sharp plane handles it pretty well.

I tested the moisture content using the “match” test.  That’s a goodie if you don’t have a moisture meter.
Goes like so.  Put half a dozen matches along the plank, heads in contact with the wood, in the shade.  Wait overnight, and if in the morning, you can strike them and get a light, the moisture content is low enough to glue.
Any dampness, and the matches wont light.

Having made up all the staves, the assembly jig was next.  That’s simply a slightly oversize half circle cutout in a plywood scrap at each end of a support, like so. The cutout in this case was 80mm, it needs to be just a bit oversize to accommodate the way the staves fit together.

In the lower end of the lower section, there is a hardwood “blocking”.  That’s a solid piece that takes up all the space inside, in this case its 550mm long, cut square to the size of the inside space across opposing flats, then cut at 45deg on each corner to make eight equal sides.
That piece is Australian Jarrah, seriously hard wood, very strong, glues well.

Same with the top end, the hollow section needs “blocking” through the area where it sits into the aly tube, and a bit above where the halyard blocks are to be bolted in.  That piece is spruce, and you can see in the pic where I’ve cut away  the top end to reduce the “stress riser” where the section changes.

To explain that, a sudden change in the strength of a tube, or a beam or whatever, from one strength to another , in this case where the internal reinforcing suddenly stops, causes a much weaker area than either of the strengths each side of it.  Its know in engineering terms as a “stress riser” and that odd shape that you can see in the pic is a good way of ameliorating that problem.

Now, its about time to lay the spar up.

This procedure is the same whether it’s a short item as these are, or a full sized mast for a much larger boat, or anything in between.

I’ve made up shock cord lashings, pieces of car tyre inner tube with toggles, or suchlike will do.  Use lots. Have them ready to hand before you mix the glue.

I had at this stage tried a dry layup to check that the jig was right, lined 8 of the staves up ready  and it was time to get on with it.
Mix the glue, not so much thickener in this, it needs to be brushable, almost a syrup consistency rather than the peanut butter thixotrope that we usually mix with our epoxy glues.
Brush the glue in, in this case it was 5 pumps each of hardener and resin with the WEST system pumps, well mixed, glue powder added and well mixed in, and at it with the brush.  This was a 30mm chip brush, cheap enough to throw away later, it actually costs less than the solvent you’d use to clean it so in the bin it went when the job was done.
Brush coat all of them, then four sides of the blocking  piece.

Drop one stave into the jig, slip another into the notch, then a third, sliding the assembly down and around as you do so so its sitting in the bottom of the jig.
Drop the blocking piece in, making sure all the ends are flush, then coat the top four sides of the blocking, and carry on with adding staves until the last two are ready.
Drop the second to last one in but leave its vee edge sitting up, you need to drop the last one into the vee of the one on the “other side” then lower both down so the vee engages with the square edge of the other.  You cant get it in otherwise, and its not possible to slide it in from the end.
Practice this on a dry run, do it a couple of times if you’ve not done it before.

Massage the assembly into shape so all the joints are fully engaged, then tie the assembled spar together by wrapping your shock cord ( or whatever) ties around it, work it over again to make absolutely sure its all properly clamped, then go away and leave it until tomorrow.

What you get when you come back is a peculiarly shaped thing, that will need a lot of work with a plane and sandpaper, and there are plenty of articles around that will explain that, but suffice it to say that you’ll make a lot of shavings, and that long strokes, changing the section from the odd shape to 8 sides, then 16 sides, then 32, then round, is the way to go. 
The part of the section that is going inside the aly tube doesn’t have to be finished to a high standard, its going to be completely smothered in epoxy glue before its slid into the (cleaned out with an acetone soaked rag on a broom handle ) aly tube, so with the aid of a template, a dead sharp no 3 Stanley plane and an angle grinder with a 40 grit disc on it, I made a big heap of shavings and dust.  It took a good hour and a half to get that fitting, patience is a virtue , as is a pair of strong arms.

So there it is, I’ve some work to finish the lower end, I need to cut the tenon that fits into the lower mast step and put a couple of screws countersunk into the aluminium to hold the woodwork in place, just in case the epoxy doesn’t stick, and its there to be a filler more than anything as the loads are all sideways, and that end of the job is done.
I’ll be back in a day or two with the top end.

Below, I've posted a series of pics that show the whole operation.

 Test cuts, note the blade of the saw tilted, the position of the fence and the height of the blade.

 16 staves, milled to thickness and all cut to width, the vee cuts done, drying out to make sure that the glue will take.

 45deg cuts to make 8 equal sides.

 The internal plugs, the reddish one is Jarrah, high strength but heavy, goes in the butt end of the mast, the other is spruce which goes in the top section. They're sawn to the shape of the inside of the 8 sided birdsmouth section spar pieces.

 This odd looking end cut is there to reduce the "stress riser" where the plug ends.

Second stave in place, all of them are pasted up with the epoxy glue so speed is needed. Note that I do this sort of work in the cool of the early morning to give me more time. 

 Thats three staves in place, now to slide them down lower in the jig, at this stage they don't have to fit perfectly, the final assembly with the shock cord clamps will pull them together.

 A nice close fit.

 Half the spar laid up, and the "plug" being fitted in.

 One at a time, laying them in over the plug that will reinforce the mast lower section.

 Last stave being slotted in. The last one requires the previous one to be eased out so the two can fit together then be pressed back in.
 All glued up and the shock cord strapping holding everything in place.
All strapped up. I'll leave this for 24 hours to make sure that the glue is dead hard.

 Time to make shavings.

 More shavings.

 Template being used, the open semicircle on the right is the template for the outside of the aluminium tube, the one on the spar is the smaller diameter for the inside.

 Almost there. Just some fine shavings and a bit of sanding to do.

 Hey, it fits! Now to pull it out,  clean out the inside of the tube, coat  the wooden section with glue and slide it back in with a couple of screws countersunk in, to hold it. Just for insurance.

The pile of shavings was about double this by the time I'd finished. It represents a certain amount of sweat, but it was a fun job. One to go.

Monday, September 30, 2019

Masking and filleting the outside of the hull.

Long Steps is coming along.

Progress, a little at a time but progress nevertheless.  With the hull and most of the internal structure all sorted, its getting down to smaller pieces and the small but time consuming jobs.  Todays was to grind the edges of the chine tapes down a bit, ready for me to run a fillet of filler along the edges and smooth things off ready for the fiberglassing of the boats bottom.
The other job today was to fill and fair the undersides of the top two lap joints, the lowest one will have that done after the fiberglassing of the bottom.

Once that’s done then the skeg and the little protective guard alongside the “offcentreboard slot” can go on, then its filleting and finishing the hulls outside, up to the gunwale, ready for paint.

I’ve taken to masking the fillet lines. It takes a few minutes to get the tape on but makes for a much tidier job.  Microballoons with a little bit of glue powder mixed in does the job, fills any little gaps and will protect the edges of the plywood planks.  I’ve run a gloved finger with methylated spirits ( denatured alcohol) along to smooth it, that reduces the work required to smooth it.

 Taping the bottom chines, these get more wear and tear than other parts of the boat, still have one more layer to go, that being a full sheet of 6oz cloth from the lowest chine across the bottom to the same place on the other side.  The other chines / lap joints are masked off ready for the protective fillet of epoxy and microballoon fillets to be run along them.

It pays to strip the masking tape before the goo has had time to set off hard, I've not done the lowest ( highest as you look at the pic) one as the glass thats going over the boats bottom will come down to that lap, be trimmed off there and only then, will the fillet go along, the intention being to hide the edge of the glass under that.

Painting is not that far away. I’m looking forward to that. Five coats. One of primer, lightly sanded to get brush marks out, then two of high build undercoat, this wet sanded with 180 grit, then two of top coat. 
I’ve decided on rescue orange bottom, black boot top line, and pale green topsides with a hunting green or British racing green topsides strake.  Then very pale green decks and cabin sides, same inside the boat, and a rescue orange cabin top.  Yes, I want to be easily found if need be, I’m hoping to take this boat a long way from her home port.

In between doing things with sticky stuff on Long Steps, I’m making recovery guide wheels for Spooks trailer, at present there is nothing to hold her straight as she comes up the trailer,  so some mods there, and a chest of drawers to replace the MDF chest that fell apart, that’s my pantry in the big ship. I’m getting ticked off with not having somewhere to store provisions so it was beyond time I did something about it.  Two sheets of 12mm construction ply, lots of screws and a big bottle of glue have gone into it so far, nearly done.

 Indy thinks that all work and no play makes both of us dull people. "Well, throw it then". 

Monday, September 16, 2019

I'm getting more done on Long Steps

With some of my other commitments dealt with and the weather warming a bit, the start of spring being just a week away, I'm getting a bit done on Long Steps.  Some friends came and we flipped her over, ready for work on the bottom and I'm getting her faired off ready for fibreglass.  There are patches where tape does the job, that being around the "corners, and along the chine between the bottom panel and the lowest plank, and the corners of the transom to planks and the stem.
I've three layers of 6oz tape wrapped around the forefoot, there will be two more over that, the intention is to protect the edges of the plywood where the boat will be pulled up on a beach or a boatramp. The next two tapes will run along the chine then a sheet of glass will run from under the lowest plank lap joint across  to the same on the other side, then the skeg goes on over that.
I've also put a patch on where each of the rudder fittings will bolt on, thats to reinforce the high stress area where those fittings will be seated.
I don't think that I've mentioned it before, but I've bored the holes for the rudder fitting bolts well oversize, filled them with epoxy mix then re drilled them, that to prevent any leakage getting into the end grain of the plywood as well as increasing the strength through the transom plywood and the big doublers inside.

But todays little triumph is that I've made the fittings that will hold the bolts in place.  The problem is that with the after deck on, access to the inside of that space is very restricted, so I've made some 6mm stainless steel plates, threaded to take the bolts, the bolts will go through these and have a locknut on them to ensure that they cant come undone, then be screwed onto the doublers inside the transom as a permanent fitting. 
The bolts protrude out through the transom, neoprene "o rings" over them, and the fittings placed over those with washers and nuts to secure them.  Here are some shots of the fittings.  
A warning, stainless steel is tough, not hard, but tough, I broke a tap doing this, in part because I didn't have the correct drill size for the tap. Only 0.2mm difference, but like I said, that stuff is tough.  Its cheaper to go and buy the right size drill than lose a tap.

This is the lower one, the ends of the plates are shaped to fit the inside of the planking.  The bolts are the wrong way around but you get the idea.  The fittings by the way are from Duckworks, they're great. 

Wednesday, September 4, 2019

Half a million views!

I just noticed that this blog has hit half a million page views, thats a lot, a lot lot!

In spite of my having been very erratic in my posting for a while, the views keep accumulating, thank  you all, thats very encouraging, with the new season coming up and life seeming to be getting to be a bit more under control, more sailing, more designing and more building of boats, there should be more material to write about.

Thanks again, all of you.


Keeping the phone charged up while away.

With spring just around the corner, warmer weather and the promise to myself that I'm going to be doing a lot more sailing this summer, its time to sort out the small annoyances from last year. One of those was "how to charge up my phone".  The phone being my GPS, my weather forecast receiver, my music machine, my camera and occasionally my communication device.
Now my phone is a Samsung A10, it works fine but a word of warning, with the screen protector on its very hard to make the touch function on the screen work.  If you're going to put it in a waterproof case be aware that it may not work.
But that aside, I wanted to be able to recharge it while away.
I'd been thinking of a solar panel, a deep cycle car battery sized battery, an inverter and a bunch of wiring, but I've other things to do with my time, things like fixing that unprintable excuse of a trailer that Spook lives on, fitting the new to me ( its second hand but unused, thank you Trade Me) boarding ladder, some paint and a few other things.
When I get a statement from FlyBuys loyalty points each month, I'm in the habit of checking to see what of interest that my points might qualify for, and this time, "Bingo", I was about 40 points short of a BioLite solar panel charger.
I do on line surveys for a survey company, mostly consumer or insurance but occasionally political (boy do I have fun with those ones) surveys, each one worth a few points.  In fact I get more points from these than from buying goods or groceries, living on my own I dont spend a great deal so they only add up slowly, the surveys being helpful in that respect.
So, a few surveys later I hit the target and ordered the BioLite panel.

I tried it out a couple of days ago, on a coolish winter day, some cloud and a watery sort of sunlight, it took four hours to take the phone from 40% to over 80%, it will run for two days on the latter charge.
The unit has a battery in it so can be charged up, hold the charge and be used later to juice up the phone, the VHF radio, the cabin lights, the anchor light or the torch.   Its a good trick, compact, seems robust, easy to use, and I think its going to be very useful.
Here's a review.
And here's the advertisment.

Saturday, July 20, 2019

Wintertime is not all gloom.

It’s a particularly lovely morning. Wintertime, one of those clear, perfectly still days that we get at this time of year  and I’ve just ploughed my way through the mornings chores, and am sitting up in my bunk contemplating the day.
My friend Paul will be calling in this afternoon, he’s always good for a chat, I’ll be baking scones, something that I enjoy but which is not worth doing just for me alone so that’s a double win. Good company, some good food and a new lemongrass and ginger tea from the Charity Tea company down the road, that’s an afternoon to look forward to.

In the meantime, it will be full tide in an hour and a half,  by then the mist will have risen from the water, the sun will have a little warmth in it and there will be enough water in the channel  to carry me rowing up the river for an hours exercise.  Some people go to a gym. “Not me” says I.

I have a habit of watching the on line auction sites for interesting collections  of boat fittings, as a chronic, serial boatbuilder I’m rigging at least one new boat each year and the cost of fitting the boat out adds up very quickly. So buying the  odd second hand bits, sorting them into boxes by type and putting them on the shelf means that I have what is in effect my very own, if sometimes showing a bit of wear,  yacht chandlery.
I’ve scored a couple of those of late,  among the bits and pieces are the cheek blocks for Long Steps boom, two reefs worth,  one of the rigging screws that will be part of the tiller to rudder linkage,  some marine grade 12 volt wire that will run current from the solar panel on the after deck to the charge controller then the big battery, and a double fiddle block with becket and cleat that will likely be the bottom mainsheet block.
All that plus a heap of bits for the boat that will inevitably come next.

The project on the drawing board is progressing, slower than I’d like as we have family issues that means I’m having to stay at my mothers home a few days a week, sisters and I take turns so its not full time but it does take me away from  my interests and usual occupation.
While it feel odd sleeping in the bed that was mine 60 years ago, I’m not really complaining. I know that our efforts there are appreciated, while she is worried about taking up my time, I did tell her “Mum, you wiped my bum when I was very small, and while I don’t expect to have to do that for you, its no problem to be here to help”.

But the boatbuilding too has been slow, there has been so much else going on.  Spook needs maintenance, new boom and gaff jaws, the bilge pump has swallowed something that’s choked it, and the trailer! Don’t ask about that accursed thing, it was designed for a rather lighter power boat and its problematic in the extreme.  I’m going to have to throw some money at it as I’m not set up for heavy metalwork and welding.  
And that’s just one of the eight boats in my fleet.

There are a group of Little Black Shags working a channel just outside my window,  at this time of year they line up line abreast and move along the channel driving the small fish ahead of them.  They’re really organised, probably 10 or 12 of them working for their breakfast. Fascinating to watch, like the Royal Spoonbills they’re only here at this time of year, several species of sea and estuarine birds come and go on a seasonal basis and its wonderful to be able to see them here. Once I got to know them, I found its like having an avian calendar that marks the seasons, it will be springtime in a while, and the oystercatchers will be back to mark the longer days and warmer sun.  They’ll be very welcome.