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Further progress – Stem Knee, Chain Plate Reinforcements, Internal Skin Laminates

Mast-step Bearer

I am now busy with the Inner Skin which is laid up in sections between each bulkhead. My original plan was to  roll the boat to 45 degrees either side with the intention of making the internal laminating easier. After a trial doing one section with the boat inverted (bottom up), I found laminating overhead difficult, but almost manageable to my stubborn character, so I decided to continue in this way as there are some advantages. For one thing I stand on level ground, further, the rubbish all falls out of the boat, and as the boat is set up level, fitting up the internal panels is easier.

 

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The internal structure between Bulkheads 2 and 5 provides support to the significant rig loads, requiring much thought before the final installation and the taping of Bulkheads 3 and 4. Both bulkheads needed to be installed before the internal skin in this area could be started. This could only happen after I had sorted out the Mast-step Bearer.

 

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The original Eric structure is massive even by 1924 standards. The origins to the Norwegian working vessels from which the Colin Archer and subsequent Atkin designs where based are very evident.  Note the keel timber of 250 x 300mm and massive Stem and Stem knee!

The original Atkin design Stem Knee provides support to the highly loaded Mast-step but without much additional support of the metal (lead or iron) Ballast Keel, which is normally the case with Sloop or Cutter rigs. The Eric ketch rig has the mast base much further forward resulting in the mast-step being located right at the forward extreme of the Ballast Keel.

 

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My Eric CSP design is very much a hybrid of timber strip plank and composite sandwich construction. Elements of both construction methods sometimes providing a structural duplication, both belt and braces!

The composite hull is essentially a monocoque structure and does not rely on the massive timbers of the original traditional carvel planked and bolted together structure.

A mortised join provides a strong connection between the laminated timber Stem and the keel timber. This is further supported by the planking bonded to the structural members and the external and internal skins.

I have extended the bearer to incorporate the Stem-knee, all in laminated Tasmanian Oak.

 

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The previous profile view drawing can be a bit misleading. Looking down between Bulkheads 2 and 4 the Stem is fairly narrow with the keel plank increasing in width as it runs aft towards Bulkhead 4.

The photograph above shows a narrow section of the bilge has been skinned and Bulkhead 3 has not yet been fitted, to allow access to install the Mast-step Bearer. Due to a high likelihood of fresh rain water ingress from the mast, I have sealed all exposed timber in this area with epoxy resin and at least one layer of woven fabric.

 

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After a number of bending failures I eventually determined the correct steaming duration, and using a metal tension strap to prevent splinting on the outside of the bend, I formed the planks and then glued these together.

Tasmanian Oak (mountain ash) is well suited to the application as it is relatively hard with good cross grain compression strength and is suited to steam bending.

 

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Here the Mast-step Bearer is dry fitted, for the umpteenth time,  after incremental trimming to size and adjustment for the small amount of spring back after steam bending.

 

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Finally the bearer is bonded in place and taped to the Hull; the remaining bulkheads installed, and the internal skin completed, section by section.

 

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A view at Bulkhead 5, the forward end of the Cabin, and through the Heads compartment into the Forward Cabin. Bulkhead 3 has limber holes, although most bulkheads form sealed compartments and will have drain-plugs, not limber holes.

Chain-plates

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The soft western red cedar strip planking has been replaced with solid GRP laminate at the chain-plate locations to provide a hard bearing surface for the chain-plate bolts. The outer line at each location showing the extent of the taper.

 

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Prior to installation of the bulkheads an additional reinforcement patch was applied then  the planking was cut, tapered and a solid 14mm thick laminate at the chain-plate mounting locations was laid-up.

 

Internal Skin

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After a careful 40G orbital sanding, a seal coat was applied on a cooling temperature in the late afternoon to the section adjacent to the bulkhead.

 

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First step was the keel patch. Eventually my juggling wins and more of the patch stays put than falls off.  Then I can relax a bit and and consolidate the laminate.

 

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The first ply is the interface 200gsm plain weave cloth applied dry onto a resin coat and wet out in-situ.

 

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The double biased stitched fabric forming the bulk of the inner skin laminate is wet out on the bench, and then rolled on.

 

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Finally a further woven ply is applied and followed up with peel ply.

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And the first section of the cabin is completed, with approximately 50% of the internal skin now completed.

 


 

 

 

 

 

Farewell – Tot Ziens

Two weeks before leaving my Dutch friends said they wanted to do the Hull Outer Skin Laminate before leaving. As time was tight we made job list AND a daily hit list.  It seemed to be just about possible, we should at least get one half done, if not both sides, depending on the weather. The first week would be fairing and preparation. In theory (my best guess!) 148 hours estimated, with four of working we would have 160 available (40 hours per person), excluding unplanned work which should never be underestimated!

Prep

At the end of the week we were very pleased to see the end of dust and sanding. Item 9 rebates for skin fittings was rescheduled to later.

Nick setup the Wet-out Machine (impregnator). Apart from a good clean and new battery for the counter (liner meters) it ran perfectly despite being in storage for many years. Whilst possible to use the Boatspeed Custom Preg process for a very accurate controlled fibre ratio with this machine, I decided this level of accuracy was not necessary and we set for nominal 50% fibre ratio, which we monitored by weighing each roll as it came off the machine.

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Meanwhile the Port Hull Side has been given a good resin seal coat at about 80g per square meter.

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There are 5 plies to the Outer Skin, also patches for the Chain Plate reinforcements.

  • Plain Weave 200gsm interface/impact protection  layer
  • Two unidirectional layers at 90 degrees to planking to provide hoop strength (integral ribs).
  • A double bias layer at plus / minus 45 degrees for torsional strenght
  • A plain weave finish/impact protection layer

The hull was divided into drops and half girths measured for the run list.

run list

Approximately 40 kg of resin was mixed, all carefully weighed, mixed  and recorded by Bryony , my daughter.

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After wetting out and weighing to check fibre ratio, the laminate could be rolled out on the wet resin coated planking. Then carefully checking correct overlap and squeegeed flat removing air bubbles and creases. Then finally trimming excess.

And finally peel ply is applied to finish the laminate ready for final filling and fairing.

Starboard side still to be laminated.

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I calculated 76kg for each side of the outer skin laminate. The actual weight was 84kg. I had neglected to include the centreline overlap join (150mm) on stem and sternpost adding almost a square meter (3.8kg), also the 400GSM unidirectional was actually 415gsm an additional 1.2kg. And I had not included the Chain Plate Patches. So 84kg is acceptable even if my estimate is a little light.

Each drop took about 15 minutes. Laminating duration of 26 hours and 143 man hours.

The total build hours now about 2000.

Farewell  “Tot Ziens” –  Timo, Nick and Pim. Your help and good company was very much appreciated.


 

 

 

 

 

 

Putting on weight

With only a few more sleeps to the start of the GGR 2018 from Les Sables d’Olonne, there is a  lot of activity as skippers make final preparations.

See  facebook.com/goldengloberace .

It is with mixed feelings that I am watching the event unfold. But I made the right decision and in four years time I hope to have Pingo completed and ready for the GGR 2022.

Progress = Weight

BHD rep

With most bulkheads tabbed in there is good progress with the hull shell gaining weight, now estimated at 911kg with all bulkheads. This includes the internal skin in the forward and aft compartments, i.e. about 15% of the internal skin completed. In the last few weeks about 150kg of laminate and filler has been applied for backing laminates, coves and tabbing. The drawing below shows the different reinforcement types and where these are to be applied. Water tight bulkheads get an extra layer and the forward compartment has an additional woven fibre layer for improved collision protection. A chock for the  propeller cutaway is also shown.

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Looking forward, Bulkhead #1 tabbing completed and #2 bonded only. The snail trails on the lefthand side is excess glue, to be removed, from dowel repairs to the approximate 1000 screw holes.

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Looking through the Access Hatch hole in Bulkhead #1 with Stem tabbed in and forward internal laminate completed. Yes I do fit through this hole, just!

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Then looking aft through Bulkhead #5 with Bulkheads # 6 to #10 all tabbed in. Bulkhead #11 is lose and ready to be bonded.

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And the Aft Compartment with propeller chock installed, ready for cove and tapes.

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Bulkheads # 3 and #4 will be installed after the Mast Step. But first a bit of fairing in preparation for the outer skin laminate….


With a little help from my “Dutch” friends – Bulkheads

As this Pingo Project ( Build a Suhaili Replica , Sail the GGR ) moves along I’m often amazed at the interest and offers of help from friends and even strangers who soon become friends. One such old friend is Jelmer who is on the Blog circulation list. He put me in touch with three trainees from HMC mbo vakschool in Amsterdam looking for a Practical Internship for 10 weeks during May to July.

Timo and Nick have their own very interesting project researching and building a replica Monetschip .

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And Pim is building  a Wooden Jetski .      thumbnail_Screen-Shot-2018-01-25-at-17_30_30

 

 

 

 

 

My boat is at the install bulkhead stage which mainly involves trying to outwit gravity and get wet laminate to stay put on the hull internal surfaces. Optimism,  determination and a good sense of humour are essential. There are eleven bulkheads,  each with twelve construction stages. A simple chart allows us to see progress.

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Dress Planking involves knocking of the planking high spots. This is followed with filling of cracks and defects ( the planking is recycled timber ). Here Pim is carefully grinding prior filling the forward section.P1060647S

Backing laminates provide a hard bearing surface for the bulkheads. Timo is rolling out the bench wet-out laminate onto a sealed tacky resin coat. The masking tape guides  location.

After the Backing Laminate has been applied and cured the Bulkhead is trimmed to fit, and bonded with a microfiber blend in epoxy resin.

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After bonding the bulkhead a microsphere epoxy filet is applied to provide a landing for the tabbing tapes and remove the hard edge created by the bulkhead bearing on the soft western red cedar planking. Timo, Pim and Nick below.

Double bias tapes are laminated over the cove extending onto Backing Laminates and Bulkhead surfaces.

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It only takes time and patience, AND a little help from my friends.

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Hull Shell

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The Hull Shell, Sheer to Keel, is complete. 1300 hours for 1100kg  of planking plus bulkheads (not yet bonded).  Almost 1kg per hour to this stage although there is still a few hours of dressing to go.

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Dressing involves removing a minimum thickness of the proud plank edges using a small block plane with 25 degree blade bevel .

 

 

 

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After dressing the planking is given a light 40G orbital sanding. The new 700W Makita Sander comes standard with a built in Samurai Warrior who endeavours to throw one off the boat particularly when working high up near the keel and hanging on by ones teeth.

 

 

work list

Before laminating the 120kg of epoxy E-glass Outer Skin there are a few tasks yet to complete. And then I will need a few days with ambient temperatures less than 30 degrees C.  I’m already seeing 42 C at one meter off the floor and 46C higher up nearer the roof, so it may be March 2018 before the outer skin laminates go on.  There is plenty of fill in work to keep me busy until then including the Rudder and False Keel.

 

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Knees, stealers, two short planks

If I’m not going to get this boat finished for the 2018 GGR then the 2022 GRR seems possible, even with my very slow progress. There will be much to learn from the observing the 2018 race, what works and what does not.

Current Progress includes the Stern Knee installed, tapered stealers filling the gap towards the keel and a few garboard planks still missing as I’ve used up my entire stock.

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With most planks on the hull is now taking shape.

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Up and down the hull sides so many times its now second habit.

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Ducking for head room.

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Or stretching. The last few planks are taking a bit longer just because access is a bit more difficult.

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Back to building in November…


 

Building by Numbers

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Completed

  • 2.5 months since planking started mid May 2017
  • 1.164 km of planking, fetched and carried, brads removed, sanded, cut to 36mm width and straightened, scarf joined, fitted up and edge glued and nailed
  • 4.08 minutes per linear meter to recover scrap strip planks =  80 hours
  • 2.08 minutes per linear meter to cut and glue scarf joins = 54 hours
  • 60 minutes to fit up and edge glue one plank = 110 hours
  • 150 grams of epoxy resin ( excluding fillers) to edge glue one plank = 16.5 kilograms of epoxy resin
  •  244 hours to date for planking

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Still to go

  • 30 planks to go = 300 linear meters = 30.8 hours for recovery and scarfing + 30 hours to fit up and edge glue = 61 hours

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Its time to plan to end planking. The keelson trailing edge is dressed to provide the correct angle relative to planking by extending the power plane’s base with a batten to give a rough finish angle. A follow up with a shooting hand plane will get the angle exact relative to planking. Its also time to add a harness, and maybe a hardhat, to the shopping list.

P1040507S And now also to improve scaffolding as there will be yet plenty of work to come at height. Thanks to Colin H at least I have the basics. AND now you know what the ropes are for!

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Breaking News

Abhilash Tomy will launch his Suhaili Eric Replica built at the Aquarius Boatyard in Goa India, tomorrow 7 August 2017. Looking good…

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Don McIntyre the founder and organiser of the Golden Globe Race 2018 has made a pre release announcement in the The Coastal Passage magazine (free emag worth subscribing to..) of his steel Joshua One Design (as sailed by Bernard Moitessier in 1968 Golden Globe Race). At 15 ton she is twice the size of the Eric (8700 kg). More information in TCP #85, pages 13 and 14. In theory the Joshua will be 21 days faster that the Eric for the GGR see Still Planking Blog based on average speed to length ratio for heavy displacement boat speed. For owner builder GGR entrants a Eric CSP one design offers an alternative solution. More to follow…

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