Tag Archives: hull build

Lifting the Boiler In

With the snow too deep to open the doors today, a few words on the last couple of weeks work seem appropriate.

We are still working towards an April launch, but there is a fair amount still to do.

Cabin and Cockpit Soles

We were lucky enough to have some oak (new) and mahogany (very old) floor-boarding donated to the project. So the cabin has the oak and the cockpit the mahogany. This involved assembling the boarding into “blanks” and then spilling and cutting the required shapes from the boat.  (it also involved wrecking a set of planer blades when I missed a couple of old staples in the mahogany) This inevitably requires a deal of tooing-and-froing and careful adjustment. We opted to lay these directly on the floors, while we could have gotten them an inch or two lower, the trade-off of headroom, stability and work mitigated towards the simpler option.

Clamping the boards into a blank

Cockpit sole ready to fit

We also decided to make the sole plates around the engine and boiler of aluminium chequer-plate. This would provide a better under-foot grip and withstand the heat/oil better than wood. We used 3mm plate reinforced with 30mm x 50mm x 2.5mm  aluminium angle pop-riveted underneath.

It all looks quite neat.

Installing the Boiler

Much earlier in the process I made a mistake in fitting the funnel “permanently” to the casing. It’s quite neat but makes handling the boiler rather hard. We concluded that we needed to use two chain hoists (one for each side) to stop the chains fouling the funnel. The same process of  lifting the boiler then sliding the boat underneath. It actually took two attempts to get enough lift to clear the cockpit sides, but went fairly well…

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The boiler is mounted on four lengths of 50mm steel channel (two fixed to the bottom of the boiler casing in the “n” position and two attached to the bearers in a “u” position. We opted to notch the floors to get the boiler and inch or so lower in the boat, and ran it as far astern as possible to provide the best access to the cabin hatch. (Sorry for poor quality of pictures – the barn is quite dark).


The planning worked and there is just room for the battery to sit fwd of the boiler in-between the boiler bearers. We opted to put the boiler pressure switch inside the cabin (being 240v and all!) and fixed the switch/fuse panel to the aft cabin wall, so now we are just wiring up, and trying to make it all as neat as possible….

Here is the current version of the wiring diagram, but this is subject to modification and additional fusing is needed I think on the bus-bars.

wiring plan V1ish



Engine Meets Hull

Just a note to commemorate another milestone. Yesterday we (neighbour Mike and I) lifted the engine into the boat! Hurrah!

We had spent a deal of time debating how best to do this, with the hydraulic bucket on the tractor being the initial option – but in the end we both felt a bit “windy” about working under the engine held up by an ageing tractor, and instead opted for the “trusty” Chinese chain-hoist strapped to an RSJ in the roof of Mike’s barn. We then picked the engine up, and manoeuvred the boat under the engine. To make it more interesting, we really don’t know how heavy it is – but the two of us could not lift it by hand to get it to the engine crane to put on a trailer for the trip to the barn (200yd push in light snow!)

The decision as to installation was to epoxy four M10 studs into the engine bearers and then use nuts on the studs to secure the engine bed down.

Woodwork Meets Engineering

This was another point in the build where the “looks good to the eye” world of boat-building meets the “accurate to a fraction of a mm” world of engine and transmission.  The key was that the hold-down studs were in the middle of the bearers (for maximum strength) and the engine’s “cam-belt” pulley was truly in line with the pullet on the prop-shaft.

This inevitably leads to an hour or two of “eyeing it up”, followed by a couple of goes at “marking it out” followed by that moment where one “girds ones loins”, picks up the drill and “goes for it”!

With the holes in and the studs loosely in place we tried to wrestle the engine onto its bolts while it swung on the hoist. Eventually it was done, and checked that it would all line up.

Leaving it overnight, we came back this morning, re-slung the engine to get it to better hang level, then lifted it up, removed the studs, filled the holes with neat epoxy, let that soak in and then re-filled with thickened epoxy. Then filled the drip tray, engine spacers and lowered the engine back into place, fitting the studs from above this time – some amount of fishing was needed to get all the studs properly located into their holes, but it all went together, and is now “setting” overnight.


Just a few to provide the flavour of the process…(as usual, click for a bigger pic). Boiler next!

Befur in the Barn

Befur in the Barn

alles up!

alles up!

A bit of adjustment

A bit of adjustment

Engine Installed

Engine Installed


Engine installed - view from stern

Engine installed – view from stern


Providing some Direction – Befur gains a rudder

Rudder ready for fitting and varnish

The rudder with pintles ready for varnish and fitting

One of the major outstanding jobs on the hull was to build a suitable rudder. As Befur is meant to sail (as well as steam) we wanted to make sure we provided some thing effective.

Researching the subject covering everything from historic articles on Chinese Junk development to the Steamboat Associations’ handbook and designers from Selway Fisher to Dave Gerr’s excellent book on ship design and lots of trawling of the Junk Rig Association’s web site we discovered some important facts:

  • Traditional Junks had “rudders the size of barn doors” – so delicate little daggers seemed inappropriate.
  • Aerofoil profiles work best – the NACA profiles are well documented.
  • A balanced rudder would reduce the requirement for Charles Atlas courses for the helmsperson.

Balance and Profile choices

Balance: The idea of balance is that the rudder is built with part of the blade ahead of the rudder-stock, so as it is turned some of the force of the water helps with the turning, off-setting the tendency of the rudder to want to return to the straight-ahead position. This reduces the effort needed to steer the boat.

Clearly, there is an upper limit to the amount of balance included in the design, or the rudder will continually try to swing into “full lock”. Reading up we concluded we would aim for 20% of the rudder surface area to be ahead of the rudder stock. We failed to recognise that of course the actual pivot-point of the rudder is not in the centre of the rudder-stock but on the centre line of the “hinges”/pintles.

So our actual balance is somewhat less than this intended 20%, so we will see. in time. if Befur is easy to handle. Of course handing is likely to vary considerably between steam and sail, so it’s probably going to be a compromise.

We will initially just fit a simple tiller to control the rudder, but the plan is to also install hydraulic wheel steering, as it will not be possible to control the engine and reach the tiller from the same seat – so some “drama” will probably ensue as we attempt to pick up a buoy or dock.

Profile: While a flat plate rudder will work, they produce more drag and deliver less “turning moment”. The better plan is to make the profile of the rudder an Aerofoil (Aquafoil?) shape. This causes the rudder to produce sideways “lift” helping to pull the stern around.

It emerges that standard aircraft aerofoil sections are appropriate, and the most well known are the NACA profiles developed by the American National Advisory Committee for Aeronautics. This is because water and air can both be considered “fluids” (Hence all the work on Fluid Dynamics in Formula 1 car design).

These profiles are identified by 4 digit codes, the first two numbers indicating the “camber”  of the section and the second two numbers indicating how “thick” the profile is. As the rudder needs to provide “lift” in both directions (port and starboard) the camber is zero producing a profile that is symmetric about its centre line.

The “thickness” of the profile determines a) how much lift the rudder will produce for a given speed through the water (larger profile = bigger lift) and b) how much the rudder can be swung left and right before it stalls and the lift is lost.

Clearly this is also a compromise – but we settled on a NACA0015 profile – this meaning that the thickest part of the profile is 15% of the length (chord) of the rudder. Again, time will tell how good this decision was.


An old friend Nick Pilbeam from Aberdeen volunteered to come and assist in the manufacture – thank-you Nick.

We adapted the design to take advantage of the contents of my boat-building timber store. I have become a considerable fan of epoxy-composite structures and of laminated timber designs, so we started with a rudder stock of 75mm square Iroko and a blade core of 25mm thick plywood.

These were jointed via a “cross-halving” joint (with the blade inserted into a slot cut in the rudder-stock. This was then built up with lamination of Iroko and Douglas Fir.

The whole rudder was to be wrapped in epoxy-soaked glass cloth (in the same way as the hull is built), but this time finished in the clear (with varnish to protect the epoxy from the Sun’s UV radiation). This approach means that at least a small part of the boat will look like the wooden boat that it is!

Having laminated the components together with thickened epoxy, we then undertook the initial profiling with a router running on a pair of slides which had been cut to match a set of co-ordinates computed using this rather helpful web page.

In practice (after having repeatedly struggled (and failed) to correctly copy the measurements from the spreadsheet to the template) we concluded that it was not possible to accurately route the leading edge portion of the aerofoil from the template. This was because the rate of change of thickness is so fast at the leading edge, and as you need to keep the router normal to the template to get the correct profile, it was very easy to make a BIG mistake.

So we settled on making another template for the leading edge and using the trusty power plane and belt sander to profile the leading edge of the blank 🙂

Some pictures:


More fitting out – and symmetry

Just a quick note, the last week or so have been dedicated to the building of the cabin on Befur, and the first stages of internal fit-out.

This has involved the fitting of the cabin sides (as seen in the last post’s pictures), and the fitting of internal bulkheads, (e.g. the walls of the loo and heads for the bunks.) This has involved more “spilling” to get the shapes from the hull for cutting of the bulkheads (a remarkably accurate process) and fitting these too the hull using epoxy filets. Continue reading


Sculpture in Epoxy and Wood

Boat building for botchers!

I have returned to work on finishing and fitting out the hull, and in the process come to the conclusion that boat building using strip-plank/epoxy is mostly a process of sculpture using wood and epoxy as the constructional elements. I must confess that this approach really rewards the botcher, as there seems to be no need for the kind and quality of woodworking skills traditionally needed – in fact I think they may be a disadvantage. 🙂 Continue reading


Fuel Tank, Mast Structure and Galvanizing

This is a hotchpotch of notes on progress we have made in the last few weeks.

I am now focusing my attention on the internal fit-out. We need to get Befur in a state to move her on a trailer to our new home in Cumbria in August, this is adding some needed pressure, to ensure we get everything done in time… Continue reading


Fit-out and Steelwork


The current process is trying to finalise the major items in the fit-out of the boat, so that I can install the major structural elements for the cabin and mast. This is a bit of a “round in circles” process, You imagine how it will be, draw it out, see it doesn’t fit, imagine it again etc. Clearly some items will fall out later in the process, but we do need to get the mast, boiler, engine in the right place and make sure that one is not sharing the loo (head) with the other members of the crew or a few hundredweight of hot steel! Continue reading