Wednesday, November 9, 2011

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.

Monday, October 31, 2011

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..

Thursday, September 29, 2011

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.


Friday, August 12, 2011

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.  


Monday, August 8, 2011

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.