Sunday, 14 December 2014

Rails and rubbers

December, week 1

Bit of a short week, fixed the toe rails and rubbing strakes. Toe rails were quite slow going, didn't want to over stress them, since they are being bent across their width, last thing I want is a scarph joint going "pop"...

All the pre-measurement was worth it - not a single deck screw fouled.




Details of the scarphs:





Work not stated on the sheetman's hatch (aft) frame and then the hatch cover.

Getting close now.....


Sunday, 30 November 2014

Iroko

Week 4

Last full week for 3 weeks before I disappear to Poland for a few months...

This was the week I tried to do the the Iroko baulk for the rubbing strakes and toe rails. I ordered the 1" diameter Iroko dowels for the  toe rail bobbins at the end of last week - hoping they would arrive by the end of this week (they came on Wednesday).

The Iroko bought earlier in the year was run through the table saw to produce 11 strips 14' x 2" x 3/4". Five of these were machined to approx 14' x 1.5" x 3/4"  (these would be the rubbing strakes) and five to approx 14' x 1.24" x 3/4" (these would be the toe rail capping).

These needed to be joined with 6" scarphs to produce 30' 6" lengths of each.

With these now unwieldy lengths, I needed some help to run them through the thicknesser for final dimensions of 3/4" thick and 1.5" and 1.25" wide respectively. This was an involved job due to the length and relative fragility (given the length - I'm always nervous of glued joints...).

Next was the job of knocking off the corners with the router; similar issues:



...but dodging rain clouds etc. worked out in the end, with the help of no.1 son and on Sunday the devoted life partner....

The toe rail cap was more involved. The rail is mounted on 3/4" high bobbins 1" diameter. The idea is that the rail covers the end grain so there will be a 1/8" overlap; it's therefore important the bobbins are central. The toe rail therefore needs to be pre-drilled with pilot holes - from the underside. If this cap rail is rounded first, it won't sit flat on the pillar drill stand - so it needs to be drilled before profiled.

In addition to this, I have to make sure the screws do not foul on the screws holding down the deck planks. This is where the polythene templates I made whilst cutting the deck ply some months ago comes to the fore, since I marked every screw before covering with the ply. Marking all the screws that might be in the way on the deck, the toe rail screw locations were marked out at 8" centres. Where there was danger of a clash, the location was adjusted so there was at least 1" clearance from any likely screw. These measurements were transferred to the back of the toe rail cap and pilot holes drilled for the final fixing.

The pre-drilled rails were then run through the router and the top edge profiled to a dome.

Next the bobbins needed to be centre drilled. Initial plan was to mount shortish lengths of dowel into the lathe and end feed a drill bit into the open end. However the end feed chuck did not have the tightest of bearings  (and why should it - it dates from about 1910...), so the holes  were not too central, plus the lathe stalled if the drill was fed too quickly, plus I was limited to the length of the drill; this meant only 4 bobbins at a time.....

The alternative was bore a 25mm hole part way through a 3/4" offcut with the pillar drill and clean out the edges 'til a bobbin fitted snugly, but could be extracted with relative ease. Placing this ersatz vice back on the pillar drill and centering with the original bit, it was clamped to the pillar drill base. Replacing the spade bit with a 4.5mm twist bit for the screw clearance hole, each precut 3/4" bobbin can now be drilled plumb centre - all 86 of them.

The assembly was temporarily clamped and a holding screw bunged in to see how it all hung together:-





Pretty good.

Ultimately the screw holes will be over-bored and filled with epoxy. These will then pilot drilled again for the final fixing. The thought be hind this is that if the epoxy deck covering is breached and the screw hole lets in water, the decks will rot from the inside out; by the time It is noticeable the chances are the whole deck will be terminal.... Not in my lifetime, thank you very much.

As a footnote, this is an unusual way to fix a toe rail. Father came up with this idea to minimise the possibility of water pooling behind a more traditionally fixed rail and rotting the deck (as it had some time shortly after he got the boat in '47). He used sawn off sections of broom handle for the bobbins - I'm sure he'd appreciate the upgrade.

As an aside, this construction makes it very handy to tie off fender ropes - no more screw holes in the deck for mooring eyes!!!



Sunday, 23 November 2014

Hatch

Week 3

With the wind up our tails and a 2 week postponement of the next job away, tackled the forepeak hatch surround.

But first, a play with my new toy. I had a struggle to flat off the epoxy deck covering due to clogging paper etc. and using a finishing  sander which really wasn't up to the job. My belt sander was too aggressive, so after seeking advice, bought a (bloody expensive) random orbit sander complete with dust extraction. This is something I had had stubbornly refused to acknowledge the need for since the barn was full of its own dust. But this beastie is different, the sanding pads are a net substrate coated with abrasive, the dust produced, which normally clogs paper, is sucked through it - extending the life of the pads by some measure. In addition the sander weighs only 2lb, a big advantage when I use it to prepare the hull planking.



What a piece of kit; sanded the whole deck in 2hrs and used just 2 pads. The vacuum extractor is so quiet, with the nifty trick of automatically switching on / off when the tool (any tool plugged into it) is in use. Still a little dodgy on my pins at the eye watering cost of it, but nonetheless, impressive.

Back to the hatch. Mulled this over for some time before and decided on profiles outlined here. The first thing was to find some Iroko long enough. An old wildfowling friend a few years back, gave me some bearers that had been used for shipping crates; they were to be tossed aside and burnt - he salvaged about 200-300 of them. All were tropical hardwood and some Iroko. They varied slightly in length, width and thickness; I wanted 4' long and 2.25" thick. There was just one and that was going to be tight to miss the bolt holes...

The cutting is quite complex because the frame is made up in 2 halves and glued in situ such that it can be removed as one piece if required later. The inner frame is screwed to the deck edge with simple mitre corners, the drip apron sits on the deck surface and is glued into a groove in the frame, then screwed into the deck (sealed with mastic). This hopefully results in a waterproof structure and fitting.

The inner frame pieces needed a rebate so the outer edge rested on the deck (for support and sealing), the depth of which was important as this would affect the total external width of the hatch. This width had to be matched with the inner dimension of the hatch cover. This rebate was cut on the router table. There was a second rebate 1/4" above the 1st to receive the edge of the drip apron. This too was 1/4" wide and deep and was cut on the table saw.

The drip apron pieces were 2" wide and only 1/2" thick. These had a corresponding 1/4" rebate cut on the lower edge and then the outer edge given a roll moulding. The dry assembly looking something like this:
  

The inner frame was screwed to the deck and drip apron marked up for the mitre:



These mitres were half lap jointed with their partner:



The whole area around the forepeak hatch opening was masked off with polythene and all the elements attached and epoxied in position.

24hrs later the assembly lifted out as planned and was cleaned up; the result being fairly good:



The final fitting will be delayed until the deck has been painted.

Next on the list was rubbing strakes and toe rails. The baulk of Iroko bought earlier in the year was sliced into eleven 3/4" strips 2" wide and 14' long - which means that each will need to be made up of 3 sections scraph jointed. Something to look forward to......


Saturday, 8 November 2014

Rudder

November, Week 1.

Over the previous week experimented with the peel ply and epoxy covering for the deck glass.

Crap.

The ply leaves a really deep weave pattern. Where lapped up the cabin sides, inconsistent contact left very irregular surface. The ply absorbs a lot of the epoxy so that when removed the actual thickness left on the deck is quite thin. All in all £100 waste of time.

I will lay on the epoxy and leave exposed - to hell with the amine blush and I'll be sanding it anyway, so there'll be no irregularities.

On the plus side, picked up the new rudder from the fabricators on Friday. After about 8 months + in gestation, 2+ years in the planning it was crunch time to see if the rudder tube went through the holes drilled the other month.

A little fettling for the hole in the hog where I had to drill from both sides, then a chamfer on the bottom edge to accept the weld attaching the base plate to the tube and then it was the moment of truth....


Astounding.

Next big test was, had I had taken the measurements correctly, and where did the top of the tube come in relation to the wooden boss....?



Astoundiment no.2.

Finally, how does the angle of the base plate line up with the hog...?



Three out of three!

All those weeks/months of turning over thoughts, methods, approaches seem to have paid off.

I just had to allow myself a little preview of (hopefully) the end result, so a mock up to reveal:



I can't test the measurements for the rudder proper until I have conducted some surgery to the trailer. The aft prop support fouls the rudder and needs to be cut off and moved forwards a couple of feet or so, but that will have to wait.

In the meantime back to that bloody epoxy for the deck.

Sunday, 2 November 2014

Last biggish repair?

October, Week 4

Snatching a few hours here and there between work commitments, managed to finish off glassing the deck and then the sanding down.

The edges up the cabin sides and over the deck edge were feathered and the whole lot washed and scrubbed to remove any vestiges of  amine blush.

Got hold of a roll of peel-ply in readiness for the next (and hopefully final coat) of epoxy. The plastic peel-ply when laid over the wet epoxy will hopefully help produce an even surface, but more importantly dispel the opportunity for amine blush, now the temperature is falling and the humidity is rising.

Looking around to finish off anything that needs a few days to complete as will be away for several weeks on work and stumbled across the replacement of the forward bolts through the hog joining the stem.

Banging them out with the bolt-nut-bolt system works just fine and all remaining 5 bolts ejected. The triangular repair dutchman that was put in by someone a few years back to replace the tail of the stem scarph that obviously had rotted; had gone the same way as the part it replaced. 



It was only ever seated in mastic, so a replacement piece made and will be epoxied in place.

Excavating the areas around the bolt heads removed, going aft there was significant rot, improving the further away from the scarph joint - as expected. Removal as much as practicable was the answer without getting too close to the underside of the garboards. Quickest way was an angle grinder and 24 grit sanding disk, Dodgy bolt head holes were drilled out oversize and plugs glued in. They were then ground down when the epoxy cured and the faying surface evened out with a plane.



A replacement piece of Douglas Fir was fashioned and epoxied in place. 



When cured, planed to fit as was the socket for the triangular dutchman and the final part of the jigsaw epoxied in place.

Holes drilled and replacement bronze bolts and the job's a good 'un.



Monday, 22 September 2014

Glass

Week 3.

Whilst I had a run of continuous days left to me, it seemed sensible to tackle possible the last big job - fibreglassing the deck.

I want to get this done before the weather gets too damp; thus avoiding the irritation of amine blush on the epoxy (likely to be impossible to clean on the dimpled surface of the glass).As usual the logical start point is the most complex - just in front of the cabin, with the intrusion of the tabernacle, forepeak hatch and curved corners of the cabin sides.

Preparation involved getting a few plastic paint kettles to mix larger quantities of epoxy and some firm rollers to apply it. The glass I already had from the start of the project, though had used some for the punt restoration a few years ago; hopefully I'll have enough left to finish...

Marking out a 4' strip that extended 3" behind the cabin front, down the side decks and 45" forward (the roll of glass is 4' wide) was the start point. The ply on the deck had already been filled and rubbed down several weeks ago, so was swept and wiped over with a tissue soaked in acetone to remove any greasy residues. Also the small strip of teak cabin sides that the glass would lap up onto was washed thoroughly with acetone to remove its natural oils.

The glass would be trimmed on the cabin sides 1/4" up from the deck and similarly 1/4" down from the overlap of the hull planking. this is done when the epoxy is half cured or "green". I wanted an even cut so knocked up a sliding guillotine contraption with appropriate spaces and a Stanley blade sandwiched between blocks of wood; one 1 3/8" deep for the hull (spanning the deck thickness plus overlap) and one 1/4" for the cabin.



The first swathe was a P.I.T.A. but eventually went down. 4 hours later it had gone off however the bloody thing was covered with bubbles centred round the nail positions... Curious. 


Advice from those that do much more of this epoxy / ply thing was that the acetone from the wipe down was probably being drawn up by the less dense filler used over the nail heads was evaporating after the glass skin was laid, pushing it up. Lay off the acetone (on the ply at least). This advice came too late for the 2nd panel...

Third panel - sans acetone - was laid down the side deck in the evening and laid like a dream.

Fourth panel around and in front of the forepeak hatch (probably the largest) was also laid without acetone the next morning. By the afternoon it had gone off and covered in sodding bubbles again!

Decided to seal the rest of the deck with a layer of epoxy to cover the bloody nail heads, This then was covered in amine blush the next morning, which had to be laboriously washed off and then the whole lot sanded down smooth to accept the glass.

Meanwhile further advice indicates that "gassng out" of epoxy is exacerbated by temperature; thus application in the morning will increase the likelihood of bubbles as the temperature rises during the day - bloody plastic boat building...

Fifth panel is a small one right at the front of the deck; now laid over epoxy primed ply and in the evening - perfect.



Trick now is to start the glassing late enough in the day to prevent bubbles, but early enough to catch the epoxy "green" to cut off the edges.

Meanwhile, I've several score bubbles to sand off and patch.

Sunday, 14 September 2014

Chainplates

Week 2.

The time had come (the Walrus said ...) to fit the chain plates. The ridiculously expensive 82 deg countersunk arrived and the mock-up for the offsets seemed to work. The definitive offsets were marked onto the hull planking.

First measure a couple more times and then centre punch the location for the 3 holes in the chainplate. Drill all three with a 2.5 mm drill and offer up the plate to the offset lines and hold very firmly in place.

Mark the position of the chainplate holes on the planking by drilling through the 2.5 mm holes just drilled. Remove the chainplate and replace with the  2.5 mm guide block pre-drilled on the pillar drill - this would ensure the holes would be perpendicular to the planking.

Drill through the planking to the extent of the drill's length and finish off through the frame with a spoke drill. A quick check on the inside confirms all holes are in line and through the centre of the frame. Bingo.

Next, enlarge the holes 0.5 mm at a time until 9.5 mm.

Back to the drill press and enlarge the holes in the chainplate to 9.5 mm and countersink to 9/10 of the finished depth.

Offer up the chainplate to the hull and check the bolts pass through the chainplate and hull whilst still lodging just under the plank lands - tight but good. Success. Only 3 more to go.




The other 3 go OK, the only hiccough is that the aft bolts are too long and I need to extend the thread a bit up the bolts - awaiting an imperial tap and die set now to do this.

It seems I might have a 12 month overseas work project in the offing and therefore extended time on the boat might be difficult in the coming months, so complicated jobs need to come forward; so that means fibreglassing the deck.

As the fibreglass will wrap over the deck and 1/4" onto the hull planking, the corner of the deck needs to be rounded - glass doesn't like 90 deg corners. Using an old moulding plane of my Great Grandfather's, the edge is knocked off. Similarly the glass will wrap up the junction with the cabin sides.  Here there is a little forethought required; when the sides are stripped for repair and varnishing, the heat gun can / will damage the epoxy of the newly glassed deck, so I need to strip back the varnish some way away from the deck. This means removing the windows...

Windows are laminated glass and not cut too well either - they fit pretty poorly. With judicious use of heat, hacksaw blade, chisel and patience the (very) old putty was mostly cleared away and they are out (not without cracking two of them). Later I will make some snug fitting templates and have some replacements properly cut to the correct shape and size.


Sunday, 7 September 2014

Bronze

September, Week 1.

Getting close to the end of my 3 month Summer Holiday and thoughts turn to the finishing straight. Stuff is beginning to go back into the boat and wherever I find brass (unless the original Admiralty screws which are as good as modern bronze) it will be replaced by silicon bronze.

With some trepidation made a shopping list for most screw lengths from size 6 to 14. It worked out at about 1,700 screws plus a dozen bolts for the chainplates and cost .........£715. When received and packed away occupied about 70% of a drawer unit less 2' x 18" x 3".

Varnishing the seats has continued all week, trying to lose the grain but proved very difficult with ancient teak. After about 20 coats and a litre of varnish called it a day. They will be laid up for some days/weeks to harden before I consider whether to fit them yet - the issue being that with continual climbing into the boat through the cockpit they will inevitably get damaged.

The webbing for the cabin bunk slats arrived and after the had been sealed and the stainless staples arrived they were all connected together. The last slats and middle screwed to the riser and locker front to prevent the lot sliding off. Worked well; and when they need to be removed all you do is roll them up!




Thoughts now moving toward making the hatch surrounds. Firstly the forepeak hatch, which is an odd shape (coffin like) and needs to be designed to prevent water getting in and not trap water so as it rots. It was this part that failed before I got the boat, resulting in all the rot damage to the planking.

A long time measuring and working out tolerances, drawing in CAD, making mock-ups of likely sections and a probable solution emerges:-


The frame will be made up of 2 elements, one forming the upright stop the other forming the watershed. The junction of the two needs to be watertight and strong. This was one  of the failures of the old one. Also this is quite a bit structurally lighter to keep the height down - don't want ropes catching on an overly raised hatch cover if at all possible. This will give an overall height from the deck to top of hatch of 1.75". The joint will be epoxied (probably G-Flex). The next decision is what wood? I have lots of Oak, but that is what rotted last time. I do have about half a dozen Iroko sleepers which I could use, but before I consider them, I need to make the faux panelling for the cabin bulkhead....

In any event, the idea is to make up lengths of the above "composite" moulding and fabricate the frame on the boat, probably with mitred half lap joints. 

But before that, the panelling in the cabin and I think the fibreglassing of the deck and perhaps the chainplates.

Sunday, 31 August 2014

Bunks

Week 4.

Varnish patching first thing each morning on the repairs to the cockpit seats and locker fronts:-


Starboard seat

Port seat

Starboard locker fronts
The main job of the week is to produce the slats for the cabin bunks. These vary in width from 1.5" to 2.5" depending on where they are - narrow at the ends and wider in the middle. Two reasons for this; less wastage from the stock timber and the middle section is where people's fat arses will sit at the dining table!

Each slat is machined to 1/2" thickness and spaced 3/4" apart.



Once cut, they're all removed and sealed with CPES to prevent mould growth under the seat squabs. For the final fitting each slat will be stapled to two strips of webbing underneath and every 10th slat screwed to the supports.

Running out of "light" jobs, thoughts turn to the chainplates.

These need to be bolted through the planking and frames (or backing plates for the aft pair). This issue here is that the frames are relatively narrow and the planking lies at an angle at the outer face. Hole drilled from outside through and perpendicular to the planking could run out too far toward the inside face of the frame. Therefore the holes need to be started forward of the centreline of the frame - the question is how far forward...

The safest solution seems to be make a mock-up of the plank/frame structure, replicating the angles and dimensions:



Judging by the results, it seems feasible, but tight. Need to decide what diameter bolt now. Clearly the thinner the bolt the more wiggle room but less strength, the reverse for thicker ones. The mock-up shows 9.5mm or 3/8", which is the size of the bolts removed, but I'm wondering if 5/16" is OK or even perhaps as little as 1/4"? 

I am thinking that since I have re-cast the chainplates so they are stepped and these now have notches that act directly on the plank edges, releasing some of the forces on the bolts by quite some margin, so I could get away with smaller bolts.



Added to the mix is that the forward bulkhead is fixed to this frame, so too far towards the back edge and the nuts of the chainplate bolts will foul with the bulkhead panelling...



The circles above show the old holes (I would aim to get them all in line and maybe vertical...?). This introduces another little issue - I want to drill as close to the centre of each plank, but it would appear that the top bolt must pass below the main beam and that is only about 1" above the bottom edge of the sheerstrake... hmmmm.