Port holes 1

A standard wylo2 has 10 portholes. 5 on each cabin-side. Eight of them are 6" (150mm) diameter and the two forepeak ones are 4" (100mm) diameter. They are small size for great strength in open ocean, unlikely to break open when slammed by a huge wave. The designed sizes are carefully proportioned to the boat and look pleasing to a discerning eye. They make up a fair portion of the boats character.

I'm going for simple fixed port lights, which will have some external lexan or perspex on sealant and galvanised through bolted. This is the most economical way to start off and there's little chance of an annoying drip or worse. Also there is no danger of dissimilar metals which could cause electrolytic corrosion.

 (For ventilation I'm counter-acting the lack of opening ports with 3" high hatch coamings to stop deck wash, a large fore-hatch, sizeable opening skylight, 2 dorade boxes, canvas spray dodger on the main hatch etc)

Foreground is the galley port light. Next 2 are for the main saloon.

To make the fixed perspex port lights.

• The deck and cabin sides were fully welded up first.
• The portholes were marked/scribed on from the plans. 6" and 4" round templates with center hole.
• A small pilot hole is drilled at each portholes center
• Another template with 8 outer fastening bolt holes was made up.
• The 8 attachment bolt holes were center punched for each port (separate 4 inch port template also made). 
• Then a cutting jig was created. It has a central pivot point on a slide clamp, attached to an arm with the oxy-acetylene torch on the end with small wheel.
• The pivot point goes into the center hole and the oxy torch then describes a nice arc just inside the 6" and 4" diameter scribed lines.
• Small angle grinder or wheel to trim up the edge to scribed lines.
• 1/4" attachment bolts holes were drilled out.

Next phase - get perspex cut and drilled.

Other options are possible.  Nick used his salvaged bronze portholes. Some rubber and small hose around bolts was used to isolate the steel from the bronze to stop electrolysis from occurring. Some of these are opening ports.

Some wylos have 1-2 opening ports at the forward end of the cabin/fore peak. This allows air to blow straight in there, but you could get some water/rain in there onto the bunk  if not attentive.

I've seen a wylo with home-made stainless opening ports machined in a sugar mills workshop during the slow season.

As mentioned previously the aft bunk/stern opening port hole is a good optional extra if you have the time-budget. Tai Taki 2s transom port can be left open most of the time while on board. Its under the overhanging transom and is usually to leeward when on an anchor or swing mooring.

My transom port is 7" diameter, just astern of the quarter berth area. It's well above the static waterline (hopefully the careened waterline too). No bolt holes are drilled yet.. If i cant find a suitable old opening port hole, then  the plan is to make an internal opening port with galvanised frame. If you are in a hurry to launch then it probably would be better to not have this port hole (as per the plans).

Another reason for fixed side ports. I met a yachty who owner-built a 50ft yacht with side opening ports. She was tied up to river piles. While the crew were away ashore the tide went out and the boat fell over downhill away from the piles, when the tide came back in the yacht filled up via the open ports and the hull was totally submerged. The yacht was salvaged, pain-stakingly repaired and sold. 

As a result of this story I'm trying to confine anything that opens to above the extremely heeled careened waterline. I'm sure it's possible with a wylo2 as nearly all the hatches, dorade pipes etc are inboard around the center line. Omitting the port side lazarette hatch entirely could also make the hull inherently safer and faster-easier to build. I have a large lazarette hatch coaming already in place,  its advantages are in port ventilation and easy access below. It will have to be kept dogged down at sea or when unattended in tidal ports.

Ballasting

Wylos are usually ballasted with scrap steel but some have used lead. I chose steel partially beacuse 2 cartons of beer in exchange for several tonnes of worn-out excavator track pins was a bit cheaper than a few grand for lead ingots. It was about another carton for heaps of scap steel punchings from an engineering shop. Thanks to those two businesses for helping keep the ballasting cost down. The wylo35 plans come with the scrap steel ballasting option as standard. (But more so because its designed for scrap steel. See the end of this post for thoughts on lead).

Bit of pre-ballasting preparation. Grinding a weld near the 4" pipe mast support post, which runs from the steel deck head to the 12mm keel base. A nice structural member to transfer mast compression to the keel. It also helps prevent the wide flush deck from compressing inwards in the middle (Should handle pitch-poling forces, but havent heard this happening to any wylos as yet)

It took a few trips in a stout ute to bring the ballast to the yard. Old 44 gallon (200 litre) fuel drums cut open at the top were used to move and store the pins. (caution required, old petrol drums with an evaporated half teaspoon of petrol vapour can be very explosive so i aired all drums out for ages, and used a cold chizel to cut tops off) The forklift at the excavator workshop lifted a drum full of pins onto the ute, and the 1 ton utes tray sagged down 6 inches towards the tarmac, the springs groaned, amazing how small a tone of it is. Acceleration was not great after that either and the ute rolled a bit disconcertingly on corners so it was a rather slow trip. Thanks to Kim again for letting me borrow his Tojo its was still ok after all that.

At the wylo yard i unloaded by hand into other 44gal drums next to the boat. (loading directly into the hull would have prevented double handling). The punchings were moved in small 5gal oil cans without a top, again try to move one of these...

Much later it was time to ballast the keel. The pins were lifted by chainblock in steel pails with about 15kg per trip. Lowered the pails in, then stacked the pins up in the hull fore and aft of the keel.

 

Pins under the companionway hatch.

Once the pins were ready, i hired a set of industrial scales to carefully weigh pins/punchings in an old plastic crate. A tally sheet was kept so i'd always kow how much had gone in, so it could be spread evenly and when to stop - 4,840 lbs (2,195kg) for my 35 foot fixed keel. (its less at 4,280 lbs for a 32 ft Fixed keel).

The track pins were laid fore-aft in layers. each pin nestles between 2 pins below and any odd corners or ends were packed with punchings (about 3/4" to 1" diameter). The 4" diameter keel leading edge pipe is filled with punchings only.

 The ballast is laid between frames F3 (aft end of forehatch) and F6 (fore-end of galley) in the fixed keel wylos.

Steel punchings in 5gal tins. Note the top of the ballast line chalked in on the keel box. It took a few days and a few sore muscle days after that.

Once all the ballast was inplace and close to the ballast top line, I fitted 5mm steel plates over the top of it, snug against the ballast below. It was fully welded down. A small bilge sump was fitted at F6 (lowest part inside hull for the bilge pump intakes)

A filler pipe foward allowed some oil-diesel mix to be poured in to prevent any corrosion in future, but as the ballast box is hermetically sealed by welding  it probably isnt all that necessary as the ammount of oxygen remaining inside the box  is small. (There is a school of thought that cement mortar, (or even artificial goop) between the pins is a good way of starving oxygen, holding pins etc in place and preventing corrosion. It seem to work well in reinforced concrete structures..Any comments on this one?)

If i recall correctly, the steel ballasting of the centerboard versions may be slightly different due to the shallower keel. In these hulls the ballast extends further aft to frame F7 which takes out the small keel water tank present between F6 and F7 in the fixed keel versions.

Some builders have used lead (Pb) as it takes up less space than steel. I visited a wylo32 being built near Cairns, Qld years ago. Lead ballast was used and the ballast lid plates were about a foot lower than my one. This left significant storage space in the keel below the floorboards, enough for 5gallon jerry cans etc. You would have to consult with the designer Nick Skeates before doing anything like this.

The Cairns wylo was to be junk rigged with 2 unstayed masts, so maybe it has extra top weight to conteract? I stuck exactly to the gaff rig plans Nick sent me, messing around with core design parameters like the ballast distribution was too much to risk. My take on lead ballast - It would lower and concentrate the center of gravity, this would mean a stiffer hull - able to hold sail for longer maybe go a fraction faster..but the hull would also snap back from rolls a bit more agressively making a less comfortable motion in a seaway. Its not a racing boat so i would go for more comfort at sea to arrive in better physical shape. The other problem with lead, is that if you fill all that storage space with water/fuel or other heavy items it may help overload the boat, increasing displacement far beyond the designed displacement with other negative effects to performance like cut passage speed down. It would be interesting to hear what others  think on this design subject.

Rudder and self-steering unit

A Masonite template was fitted in position to make sure that things would line up and look OK.

 Then 2" pipe forms the leading edge of the blade,   4" pipe was aligned and welded on above this. The rudder design is hollow with 2 sides made of 3mm plate, these were shaped from the template. One rudder side was attached to the 2" stock

2 triangular internal frames were tacked into position and the bottom plate fitted. (pic below)

The other side plate was fitted followed by  the small curved top plate.  

Following MIG weld up, the rudder stock head (tiller socket) and self steering trim tab were fabricated as per plans. 3 Pintle and gudgeon pairs were then fitted and the whole rudder assembly aligned before the gudgeon's were welded to the transom and keel base.

The almost finished rudder. The curved blade top can act as a step to get back on board. The trim tab gear is fitted to the aft edge of rudder blade. 

 The lower gudgeon and pintle. Protective keel extension below the rudder base.(Sorry pics on its side),

The rudder head, the main tiller hole was cut out of the transom. The trim tab tiller is on top, a 10mm rod is connected to the trim tab below, it runs inside a 19mm diam water pipe.

Below is a schematic diagram of  the Wylo2s self-steering system

A removable horizontal axis wind-vane is usually mounted up high on the boom gallows. The vanes blade made from ply is usually removable, so it can be either stowed away when in port or replaced by a smaller storm vane when the wind gets up. It is horizontally swung as this generates better leverage and power than a vertical axis vane would. (It also swings in a smaller area.) A round fixable rotating drum is used as the base of the vane assemblage to align it to apparent wind direction.

The principle of operation.

When the yacht is sailing at speed on the desired course, the vane is aligned with the apparent wind direction.

Lever arms and push/pull rods transfer energy from the vane to the trim-tab on the aft edge of the rudder. So when the boat strays off course the vane tips over and the force turns the trim tab. The trim tab then applies hydrodynamic force (from sailing forwards) to turn the rudder in the correct direction to turn the boat back on course.

The system is rugged and dependable and works in most conditions and all points of sail. I'm not sure what the lowest wind speed - hull speed are that it will operate. As it is wind direction dependent, the system is used when well off-shore. A sudden wind shift will alter the boats course. So when close to the coast line or other navigational hazards like reefs, the vane is disengaged and  hand steering used.

The vane self steering uses no electrical power as an electronic auto-helm would. It is simple, homemade and repairable by crew with the right tools.

Commercial vane systems cost allot more. A popular type is the pendulum-servo, which also uses wind and hydrodynamic force to amplify the rudder turning force.

An  electrical auto-helm draws considerable current if connected direct to the tiller-rudder. It would work well if motoring long distance. It might be possible to connect a very small electrical auto-helm in reverse to the wylo2's trim tab tiller?, but i haven't heard of anyone trying to do this as yet..

Aft deck, cockpit, hatch-coamings, bulwarks and the boat shed

Hatch holes were cut in the main deck which allowed more light and air below. The large hatches should be good in the tropics.

Then it was decision-time for the cockpit - or none. Many wylos, including the original wylo2 (pic below), have no cockpit. This allows for a broad uncluttered aft deck and an aft cabin below for a double bunk, optional stern porthole and the lazzarette which is easily accessable from inside or small port quarter deck hatch. Two fore and aft wooden toe-rails sit on the original wylo in place of a cockpit. Its easier to build too.

I took this photo aboard Nicks's Wylo2 in the Bay of Islands NZ circa 1991. The main features are the boom gallows which are incorporated into the aft rails. The dinghy davits are mounted off these. Self steering (black, vane removed) unit sits on boom gallows. The other great thing about these boom gallows is that they double as a chest height very solid aft safety rail! Something to hang onto when wrestling a big pelagic fish aboard in a big swell.

A wide skylit main hatch has fold back washboards which also functions as a fairly dry seat. The main hatch has forward end rollers and can be lifted up at the aft end over the coaming and seat down on  neoprene strips glued under the hatch. (if small triangular side boards were fitted it would also form a spray dodger). Its not the usual sliding hatch design so wooden hatch guide rails are fitted to wylo2s wooden and canvas deck (entire deck area is wooden on 3'3" draft centerboard versions like wylo2 to keep the topweight down). The mainsail is loose footed and slab reefed.

I opted for the aft cockpit version, as on my plans. Talked it over with a few yachtys. No knees up around the neck, a place to toss a flapping fish or anything else to prevent it going over the side. Perhaps a recessed gas bottle box aft? The aft deck and cockpit was made from 3mm plate. A 1" stringer is fitted below the 2 ft wide cockpits centerline to stop spring. It extends to the transom and has a 1ft wide bridgedeck/beams for hull strength.

 

An internal view. Construction companionway step ladder in place. Note the quarter tank. It is designed for fuel but i'm going to use it as a water tank (30gal) and fit a seperate fuel tank above it later. In the keel the top of the aft keel water tank is visible (40 gals). Tempoary angles support the deck and were removed after weld up.The tempoary angles supporting the cockpit end were also later removed to allow better access.

The new shed began with paperbark poles cut from the bush out the back. Thanks to Phil for towing them over with his ute. After debarking the poles  went into 4ft deep holes and were concreted in.

I added the central skylite hatch, not on the plan but fitted to many wylos.  Mine is the same style as other hatches, curved with the deck camber. It seemed more aesthetic and could cut windage a little. This will be harder to make but should have extra form strength. Some wylos have flat top hatches which are easier to make, the forehatch might need to be smaller if this is used and in theory all would need to be a bit thicker than curved hatches of the same strength.

  

In retrospect i should have added about 12-25mm  the bottom of the coamings making them 5 " wide (2" above, deck 3" below), before fitting. This would keep the internal deck head lining hidden/drier. especially if 1/2" thick slats lining is fitted. 

The 4" high bulwarks were fitted and tacked on with precut drain slots on fore and aft decks. These give wylos a better sense of security than the usual 1" high toe rail would.

6m scaffold ladders were hired to fit the 6m long 6" C-beams between the poles. The extension ladders also helped. Chainsawed the tops off , notched them and augered bolt holes through. Top hat purlins, brace straps then the old roofing iron were tek screwed on. Some 4x2" crossbraces increased the cyclone rating.

It certainly was much cooler and drier in the new shed.

Cabin sides and raised deck plating - MIG welding

The Cabin sides plates (3mm) were fitted to the 1" flat bar gunwales between the coachroof ends.

NB: I thought it prudent NOT to cut any portholes  into it at this stage, these were left untill much later after plate fitting and weld up completed. This was to allow the steel plate to keep a fair curve.

1" flat bar stringers were then fitted into slots pre-cut in the deck beams and tacked into position to complete the deck framework.

Incase your wondering, the purple things on the far right are not  alien life-forms. These photos went through a few cyclones in old caravans unattended but were foretunately saved in time.

Getting two 6x1.5m steel sheets onto the deck was solved by using 3 angle-steel ramps which were trimmed and tacked onto the deckedge. The plates were moved onto the ramps as seen above.

Then my 1/2 ton chain block helped haul them up the ramps to the deck edge.

And onto the deck. Thanks the help from visiting friends the Rusts and my brother Max from the land of the long white cloud.

Hans and Max are are both experienced yachtsmen and sail at the Russell Boating club  in the Bay of Islands, NZ. Nearby Opua is often the first port of call by yachts escaping the South Pacific cyclone season (Nov-March), besides being a great cruising ground there's also good boat maintenance yards.

The second deck sheet - both sheets were stood on edge and wirebrushing , anti-corrosion treatment given to the areas under the deck stringers before fitting. On the 35ft version these sheets were a little short so about 40cm extra needed to be added to complete the raised deck, i added this to the foward end.

The foredeck was similarly fitted. Some steel framed and wooden decked scafolding was made up around the hull about 4ft off the ground to make the cabin welding and bulwark fitting phase easier.

MIG welding

A 130amp MIG welder was used for alot of the 3mm deck work. It runs on any 10amp standard household electrical socket. It concentrated the heat due to a 0.9mm feed wire however seemed to produce alot less heat overall into the surrounding sheets which reduced distortion allot. This allowed for longer weld runs without plate distortion.

An argon arc gas sheild also made the welds easier and better. The mig is easier to weld with than the stick welder, just aim and pull the trigger. Once the feed speed and heat are set correctly the only thing to do is watch where you are going and move along the weld. The Argon gas bottle was hired from a local industrial gas supplier (along with the oxygen and acetylene bottles for oxy-cutting).

The MIG only had a short feed cable from box to weld-gun, so the downside was moving the box around more than the arc welder with its long lead. Also the MIG doesnt like working overhead welds as weld spatter quickly builds up in the gas sheild cowl, its far better downhand.  

Interior welding of hull

Once the hull was upright, tempoary tarpaulins went up to keep the rain out and the sun off. Sheets of roof iron covered the bow and stern deck areas.

Then a corrugated iron roof was attached over the deck beams for longer term protection of the hull. Any rain at this stage could cause corrosion. (NB: prior to hull plating, the stringers outer edges, were treated with wirebrush, phosphoric acid and zinc primer.)

 

The stringers were again treated with phosphoric acid and zinc primer. This does take a bit of time, so getting the flat bar stock block blasted and zinc primed before delivery to site is always the better option.

Now the hull was rolled, downhand interior welding proceded in a similar pattern to the outer hull welds. Before a weld was done the seam was ground out to remove any slag from the outer welds. The back-step method with short 2-3" runs was used.  3.2mm rods were used for the 5mm plate seams and 2.5mm rods for the chine/3mm plate seams.

The welding pattern was similar to the outer hull.  Once the welds were done..the tempoary 1" flat anti-distortion bars on the outside were removed. Interior welds were ground slightly to clean them up but the convex weld profile was kept for maximum strength.

For safety and comfort electric fans and ample ventilation are needed to blow weld fumes away. It could be worth wearing a welders respirator under the weld helmet at this stage.

Exterior grinding and staircase

The exterior double chine welds were ground down. A 9" angle grinder was used. It's a heavy and dangerously powerfull tool, so to suspend the weight, it was hung off a chain with rubber strap.  The top was a hook over the gunwale which could be moved along . A lightweight 4" grinder finished the seam.

Old highset house stairs from the house wreckers provided much easier-safer access into the hull than a ladder would. The stairs allow hands to be free and used for carrying tools and materials up safely.

Hull rollover

The Hull inside prior to rollover.



The waterline-pivot rollover method was used (also known as "pig on a spit" method). This was beacause there was not much space around the hull, low budget, far from crane hire yards and already had the materials on site.   Also the hull stays in the same location. It uses A-frames, heavy-duty chainblocks and pivot pipe frames welded to the hull.

Its probably a good method if an existing very strong shed already exists over the hull and the chainblocks can be attached to this instead of building A-frames.

My A-frames were made from 14ft long 6" x 12" hardwood railway bridge sleepers (as used for my building jig) and paperbark tree posts cemented in. 1/2" threadeded rods augered through held them together.

The pivots were 2" pipe welded to the hull at both ends horizontally at the design water-line. The pivot pipes were braced back to the hull with 40mm steel pipes. The building jig-angles coachbolts were removed to detach the hull from the jigs railway sleepers.

Roll-over day

This was done with the help of a few friends.  None of us had ever rolled a 2-3 ton 35ft hull over before. Three ton chainblocks were hired and chained onto the A-frame tops.

I wasn't sure if the center of balance was guesstimated right. So just incase it was a few hunded kilos lopsided, Dr Con bought his 2 ton? turfer winch, usually used haul his 4WD out of bogs. It consisted of a thick steel cable and the lever winch could pull itself along the wire rope. It was rigged amidships to help roll the boat once the chainblocks elevated the hull. A brake rope was also rigged amidships incase the hull decided to roll by its own weight.

Once all was in place the chainblock falls were hauled down simultaneously at each end and the hull began to lift and inch, two inches..a flying boat! When the wylo was about 2-3feet high, which seemed very far to fall, the turfer was hauled on..but it proved redundant because the hulls balance point was just about perfect, so only 2 half inch ropes (without block purchases) were easily enough to roll the hull around 180 degrees by hand, well almost. I had forgotten to cut a wooden A-frame brace pole off and it got caught up on the transom corner! (at about 160 degrees roll) so up the ladder to try to free it with a come-along, then the 2" aft pivot pipe began to bend!  it stopped after about 6 degrees bend as the transom corner released itself from the pole. (The pivot pipes had end plates welded on just incase the pivot pipe bent to a worst case scenario and the roll chains began slipping off). Its hard to describe the feeling of tons of hard work potentially about to crash downwards. We weren't standing anywhere under it that for sure. During all the action no-one even thought of taking a photo! (don't forget to bring a dedicated photographer to rollover day)

The final small lowering onto the keel, was needless to say, a big relief. Props quickly went in under the hull.



Note: The forgotten bush pole that caught the transom.

The wylo suddenly looked different. More like a boat than beached sub.

 Note: The tempoary cross brace amidships.

The foward A-frame and  hull pivot -bracing detail is shown in tree-cam shot above. The exposed hull was quickly covered with old roofing iron to keep any rain out.

Pivot rolling  in retrospect - Place roll-pipe braces very close to the roll chain attachment points. (On the pipe that bent was cause by the roll chain being about 9" out from the side braces attachment point.) or use a wider-stronger walled pipe, a ton or two is hanging off it. Also make sure nothing can snag up during the roll.

Other hull rollover methods

1) Another, probably better technique, is the the "jack-up and lower" method used by Nick for Wylo2. This method needs a large open area one side of the hull maybe 10m wide for rolling (best planned and set up when setting up the boat yard and build jig at the beginning of the project). Then the hull can be rolled by jacking the gunwale up to topple-point, lower the keel to ground with a block-tackle or turfer winch - 4WD winch?, then jack-up/block up the hull to upright position. The boat moves sideways about 3-4m? during this type of rollover.

2) If in town, crane hire with good operator is the quickest way to rollover. The hull can be placed back where it started or anywhere else if desired. Stronger tempoary hull cross bracing would probably be required in two places where the lift straps wrap around the hull.

Keel cooler and wings

The keel base plate is on and the sun/rain tarps are up.

The 3mm thick keel cooler plates are around 5" wide in the garboard. Improves the hulls shape and  provides good surface area to dissipate engine coolant heat.

The keel cooler actually ends where the small vertical weld is about 18" back from the leading edge. (There is a 32mm galvanised coolant crossover pipe inside here). The leading (and trailing) edges of the cooler are actually sealed voids to make a faired in shape. welds are all ground flush with the hull to reduce any turbulence and drag, which should improve keel performance upwind.

For those interested in wylo winged keels heres a few pics, below is the frame up.

The wing plate is 3mm steel, templated and welded on. The triangular frames are visible.  A small modification to the winged keel design may be beneficial from a building perspective here. It probably would have been easier to make if the wing keel top and bottom plates meet each other edge to edge , and not tucked in 1/2 inch from outer edge as per design.

Welding the hull up - outside

Welding the hull is a big job and it can makes or break a steel boat. I followed the recommended books of G.Klingel and T.Colvin. Correspondence with Nick Skeates and the TAFE night welding course also were invaluable. Prior to full hull seam weld up, the entire hull is held together by tack welds at about 6" spacings. Full weld up begins on the outside. Once outside welding is done then the hull is rolled over for internal welding.

  

Good preparation of the weld seam is important. Beveling the plate edges and leaving a 1mm gap between plates/chine bars allows for good weld penetration and also stronger weld with no hairline cracking due to shrinkage (could occur if the plates are hard-pressed together)

 

3.2mm weld rod stubs were used as spacers between frames and chine bars or stringers (These were fitted at the framing stage befoe hull plating). They were knocked out as seam welding progressed past them and the hull began shrinking. In retrospet 5mm spacers would have been better, especially near frames 1 and 2 in the bow, where hull shrinkage was greater.

I used short weld runs around 2-4" long. The short welds are needed to prevent any unsightly distortion (buckling) of the plates occuring. After doing a short weld i moved to another location to allow the first weld time to cool down. Both sides of the hull are also welded symetrically to prevent the hull pulling out of shape. Full hull welding has the effect of shrinking the hulls size by about 5-10mm.

A welding pattern needs to be followed. This is to balance out all the shrinkage forces evenly. I began near the center of the hull in the garboards (keel meets hull joins) and worked outwards towards the ends of the hull. After several meters of weld were in the garboards, i started on the lower chines..when several meters were on the lower chines , i started on the upper chines.

When a longitudinal (sub-horrizontal) weld seam reached a tranverse (up and down) plate join then i started welding down the plate join. Small plate bolts and washers were knocked out before the weld seam reached them, otherwise they would be clamped in by hull shrinkage.

 

After a weld was done the slag is chipped off with a welders hammer and wirebrushed.  Then the angle grinder was used to prepare the end of the first welds to meet the next weld. If a pinhole was noticed, it was ground out and rewelded.

Power wire brush fitted to 4" angle grinder make weld cleaning fast and easier. A face sheild is needed to protect eyes from any wires that may fly off.

The soft chines of the wylo2 are a bit unusual. They are 2" flat bar laid flat which forms the hull skin and makes a gentler corner which helps give the apperance of being a rolled plate hull instead of a hard chine hull. But the problem i noticed during weld up is this is easier to distort than usual chine methods of a solid round rod or on-edge chine bar. So i tack welded  tempoary 1" flat bars on edge, on the outside, in the center of each 2" chine bar to prevent chine distortion (photo above).

Welding seams. The rubrail was added prior to weld up. It is a 40x20mm steel channel set about 6" below  (above in this pic) the gunwale. It acts as a very strong double external hull stringer. As designed, it is also more aesthetic, reducing any slab-sided effect of the topside plates.

Some builders make the rubrail coincident with the gunwale (Klingel-Colvin method) fitting a 40-50mm preferably galvanised pipe instead of the designs 1" flat bar gunwale. This then requires an extra internal 1" flat bar stringer to be fitted to maintain hull stiffness around where the design rubrail would have been. A gunwale rubrail takes all the bumps well but it does make the hull appear to be a bit stockier aesthetically than the wylo2 design rubrail method.

I did  the hulls chines and garboards with a traditional 180 amp stick welder with 3.2mm rods and about 110-130 amps set. It takes 15 amp AC input. The 3mm hull plate joins needed 2.5mm rods with ~90 amps set. It may be better to "back-step" these joins, weld upwards starting  2" down from the previous weld.

Arond this stage i bought a 130 amp MIG (metal inert gas) welder with 10 amp AC input for thin 3mm hull plates. It  produced far less distortion than the better-penetrating 180 amp stick welder. The MIG was set at around 90-110 amps and a continuous wire feed from a spool activated by a trigger is easier to weld too. The MIG can be run gasless with flux coated wire or with an Nitrogen bottle attached by regulator and hose. The inert nitrogen gas of the MIG makes a gas sheild over the molten weld keeping out oxygen and making for a good weld without slag etc. My MIG prefered downhand welding (weld gun above weld). On overhead welds the MIGs gas sheild cowl got quickly filled up with weld spatter, never a problem with the arc welder.

The MIG has a big box, almost the same size as the arc welder, but with only 8 feet of flexible cable to the weld gun (no "traveller" as in expensive MIG welders). so moving the MIG with nitrogen bottle around was more difficult than the simpler 180amp arc welder with its long 10m cable. For me the MIGs welding advantages for 3mm plate outweighed its mobility disadvantages. (It wasn't powerfull enough for the thicker plates or chines so both welders were good for their particular uses)