Category Archives: Hull Build

Building a Strip Plank Hull
Below are posts concerning the building of the hull for Steam Yacht Befur. This hull is s strip-plank built design by Selway Fisher (see link on right of home page) and is constructed of Western Red Cedar planks clad in woven epoxy-impregnated glass-fibre cloth.

It’s the first boat I have built, so your watching a learner!

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:


The Final Push to the North

Well, as I may have mentioned we have decided to relocate to Cumbria (330miles north of current location) – this of course means moving house and more significantly relocating the workshop and boat! This decision has resulted in the gap in posts and also a final push to get Befur in a state ready to hit the road.

Continue reading



A day we thought we might be never reach, has arrived ☺.

Today we put the first paint on Befur,it’s only primer but it is a milestone.

We have decided to use Epifanes 2-pack polyurethane for the hull cockpit, decks and topsides (and something cheaper for inside)! So £480 later we have the necessary under and top coats.

Onwards! (You can tell we are excited by all the exclamation marks!!!)

Collecting the trailer tomorrow and the mast on Tuesday – real progress.



Fitting Out

Louise (having retired) has joined as a full-time worker now, and progress is much improved… She has become an expert epoxy filleter, and having two people to hold a job, or get the pencil you left on the bench when you’re up-side-down in the cabin saves a huge amount of time.

We have fitted the cabin roof, and almost completed the initial fit-out of the cabin and started on the seating (which also provides a deal of strength to the hull in the cockpit), so feel like we are moving quicker.

We compiled a (slightly daunting) list of outstanding jobs, ~80 of them, and are actually ticking some of them off!!! Cumbria is feeling closer!

A selection of recent pics:

A Chart Table!

A Chart Table!

Cabin Roof - well screwed!

Cabin Roof – well screwed!

Cockpit combing in place

Cockpit combing in place


Under the Cosh!

As we move inexorably towards August I am feeling the pressure to finish Befur ready for the move to Cumbria!

We have ordered a trailer from Gecko Trailers in Cornwall, (who’s spelling is worse than mine)! that is due to arrive in 6 weeks, so I think it’s defining a definite end date :-/ Continue reading