Still talking about oars!

Above is an image of the recommended hardwood/softwood oar, courtesy of Topher Dawson, complete with the photographer’s shadowy signature.

The oars that we will build are very similar, except that we won’t be having the ball and slot oarlock system devised by Topher, nor his spoon blades.

For that system to work perfectly it’s essential for the pins to be absolutely vertical, something difficult to achieve, given differing crew weights, for example an exceptionally heavy cox brings the skiff down at the stern. Also it’s more difficult to make accurately. Correctly set up, the system works perfectly and smoothly, but we have decided to stick with simplicity.

For those who are interested, here are details of the ball and slot system:

We intend to adopt the pin and gate oarlock system devised by Don Currie, shown here:

Here is Don’s drawing, showing construction details:

You will see from the photograph that Don has made wearing strips from some hardwood. We could use oak, or perhaps source thin strips of polypropylene, which the rules allow. He has provided dowel spacers held by strong woodscrews and the photograph shows plastic bushes round these.

These details are not today’s problem, but will give us something to talk about while getting on with the main work. In the meantime please be thinking about sourcing suitable  polyprop, plastic strips etc that can be recycled for a seagoing future.

We have now sourced sufficient Douglas Fir and Western Red Cedar to make our set of oars.  The first task is to make a cutting schedule, so that the wonderful Mr H in his mountain workshop won’t get annoyed at having his time wasted.

Marking out precisely and very carefully where you are going to cut is far more important that just charging ahead and possibly wasting expensive material. The old adage “measure twice, cut once” applies.

We have more than enough WRC, as I had to buy two pieces – timber yards won’t just cut off the length that you need. We’ve got just enough DF to produce four handles plus strips to go on the front and rear faces of the WRC, to protect the latter from dents and bashes. The strips should be 5mm or probably 6mm thick if we can manage to get that width out of what we have. Each saw cut costs you the width of the blade, about 3mm or 4mm usually, rapidly using up stock.

We will soon run oar building workshops, but for these to be of any benefit it’s important that people understand the problems and help with solutions. As  start please read Topher’s detailed instructions, copied below. We need to modify these somewhat, to take account of the flat blades, and adjust the dimensions to allow for the DF faces on the WRC.  For example I’m inclined to make these faces full length, for strength and ease of building, rather than just the length of the outboard, WRC sections. This means that the handle stock would be machined 78mm x 45mm rather than 90mm x 45mm, allowing for the two 6mm strips.

Here is an image of the handles, per Topher:

 He is suggesting ovoid, 40mm for and aft by 35 deep. I think we should go slightly less depth and also produce a pear-shaped end.

There follow Topher’s Instructions. Please note carefully the suggested dimensions, especially at the outboard end. It makes me think that our current oars are massively over-strength!

Making the Beta test hardwood/softwood oar shaft for the St Ayles oar

The hardwood/softwood shaft has a rectangular cross section with slightly rounded corners for its whole length, tapering down in depth and width towards the tip.

  • The inboard section inside the boat is made of a dense hardwood like oak or ash and the outboard section is made of a light softwood like Western Red Cedar (WRC), spruce or Douglas Fir (Oregon pine). This improves the balance.
  • The number 2 and 3 oars have the thole pin mounted not in the gunwale but in a block screwed and glued to the inside of the gunwale. This moves the pin inboard by about 70mm which allows the oar to be shorter and therefore lighter than current oars. It also allows the bow, 2 and 3 oars to be the same length, 4.3m. The stroke oar is 4.0m. “Short oars” are all 3.5m.
  • The depth and width at each station along the shaft are the same for all lengths of shaft, but the distance between each station varies with the length of the shaft.
  • The spoon blade is a spooned narrow Macon shape made from two blade halves of 4mm plywood. The blade halves are stitched together with cable ties to form a shape which is curved longitudinally and slightly vee shaped in cross section. This is then epoxied and the cable ties removed. The curve allows the light plywood to be stiffer and stronger than a flat blade and more efficient in the water. This light blade contributes to the light balance of the oar.
  • A flat 4mm ply blade can also be made.

Making the hardwood/softwood shaft:

Whatever species of timber is used, it has to be clear of knots and straight grained. In the UK the most likely timbers for the inboard are ash or oak, but elm or beech could also be used. Outside the UK there will be favoured local woods of at least 700kg/m^3 density.

The outboard timber needs to be light, straight grained, clear and available in lengths of 3.5m, although they can be scarphed. Western Red Cedar, spruce, and Douglas Fir all fit this bill. WRC is the lightest, spruce is the most expensive, and Douglas is the heaviest. Slight variations of the width and depth of the tapered outboard are in the design to take account of the different density, strength and stiffness of the three timbers. If you are using other timbers, measure the density and stiffness of a sample of your timber and pick the design for the timber which most resembles yours.

The procedure depends on what dimension of timber you start with. If you use 100×50 thicknessed down to 90×45 then make one 45mm face straight, flat and at right angles to the 90mm face. Use this face for the aft face (nearest to the cox). Mark the stations on it and draw the widths at each station. Cut this taper leaving enough timber to plane to a smooth curve. You may want to use this blank to draw around on the other shafts.

If you are using Western Red Cedar in the commonly available 150×25 sawn finish house cladding plank size, you will need to thickness it to clean up the sawn surfaces and then glue two layers together to make a blank. Your blank will likely be a bit under the 45mm thickness needed near the gunwale, but only short padding pieces 150mm long are needed because it thins rapidly.

Then on the fore and aft faces, mark a centre line and set off the depth equally on both sides of the centreline. You want to take wood off both sides, perhaps with a hand held power planer to begin with, and then a hand plane as you get near the line. Finally you knock off the sharp edges with a hand plane and some sandpaper, aiming for a 5mm radius or whatever seems right. This is to make the oar shaft more robust against knocks, and kinder to rowers.

The oar needs a big scarph joint just outside the gunwale where the hardwood meets the softwood. This is just like the scarphs in the skiff planking but bigger. Make sure the final oar is straight!

It is easiest to make a hardwood blank 90x45x1500 and work the end down to the handle size, make the slot and line it with 3mm plastic, and make the scarph, before gluing it to the outboard.

Dimensions:

This table shows the width (fore and aft) of the shaft at each station, in mm. Station 0 is at the gunwale, and the ten stations are equally spaced going out from the gunwale to the tip of the oar. The cross section of the oar is everywhere rectangular, with  slightly rounded corners, about 5mm radius.

The depth of the shaft (top to bottom) is exactly half of the width at every station.

The inboard part of the oar, from the handle end to the gunwale, is hardwood of a constant 90×45 rectangular section.

 

The dimensions vary a little for different timbers, to take account of the different density, stiffness and strength of each timber. It is important to avoid knots, especially near the forward and aft faces of the shaft.

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If making this oar out of Western Red Cedar, the lightest of all three timbers, the shaft can be made of two layers of 150×25 plank which is the most commonly available size, used for house cladding. It needs to be thicknessed down to clean up the surface, but taking off as little wood as possible. Depending on the plank, you may end up with 19-22mm thickness. A small section on each side may be needed to thicken up the 150mm nearest to the gunwale to make 45mm.

The oars come in three lengths. The shortest, 3.5m, is for short oar clubs, and all four oars are 3.5m long.

For long oar clubs the stroke is 4.0m long, and oars 1, 2 and 3 are 4.3m long. To allow oars 2 and 3 to be this short, the pins need to be mounted on blocks glued to the inside of the gunwale.

The dimensions at each station are the same, but the distance between each station is less for the shorter oars.

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The inboard and outboard are joined with a 6:1 scarph, 270mm long. The scarph joint is cut so that the feather end of the outboard is at the top of the oar, and the feather end of the inboard is at the bottom of the oar.

The handle needs to be 400mm long, and around 40mm in diameter according to taste. A good section is oval 35mm deep and 40mm fore and aft, which allows smaller hands to grip but keeps more strength. It is sensible to make a gradual transition to the rectangular section for rowers’ comfort and to reduce stress concentrations.

Varnish or paint the oar well, as the additional weight is less than the weight of moisture soaked up by an inadequate paint job.

Winter Maintenance (2)

The outside of the hull is now painted – hopefully the paint will be dry enough to safely turn the hull back onto the launching trolley on Saturday 18th January @1000 – the more the merrier for this job! We can then start on the inside, measure up the bow seat etc (see Ewan’s post below for the complete list). The oars and rudder are away to be varnished, thank you Ray & Mary.

We’ll also meet on Sunday 19th January @1000 as we only have use of John McFarlane’s shed for two weeks …

Winter job list

Work starts in  John McFarlane’s big new shed at 10.00 am on Sunday 12 January – see Sue’s comment in last post

With Selkie safely inside (see pics of the trip across below) we’ve got two weeks to complete her winter maintenance, so here goes with the start of a job list. The good news is that it’s extremely short, as she’s travelled a lot of sea and road miles with remarkably little damage.

The hull will take a few days to dry out and we’ll start on the outside, which will be ready for the first session on Sunday. 

Please treat the following as a provisional list and feel free to add suggestions by way of comments.

 Outside of hull

Lightly sand the lowest five strakes to give a key. Apply two coats top coat.  

Repair small damaged section where stem has been caught by the trailer. This needs thickened epoxy, which can only be applied once the stem is totally dry, so this area must be kept clear of paint.

The sheerstrake requires touching up where needed. I don’t think it needs a complete coat of paint.

Inside of hull

Remove mast step and stroke footrest fitting. I’ll take these away and coat them with epoxy to stabilise them.

Remove thole pins.

Clean then sand interior, removing any paint runs etc. Apply two coats paint.

Forward Seat

Make and instal a seat to same pattern as the cox seat. We can measure for this and I’ll make a kit of parts for it.

We can source a piece of heavy duty netting to go under the seat as an alternative to a locker for the anchor, flares etc.

Modifications

I’ll do a separate note about shifting the pin positions aft and changing the stroke side to starboard. Most of this to be done off the boat, apart from drilling the gunwales.

Footrests

The existing ones at positions 1, 2 and 3 need adjusting to give intermediate positions, also to make them easier to use. Eventually we can make new ones if we adopt longer oars.

Launching trolley

Add some wood to position the bow in correct position when loaded on.

Road trailer

Adjust forward block so that it engages with the polyprop strip.

Drill number plate supports for pins to give a positive position.

Jan trip to Balvicar 1 Jan trip to Balvicar 2 Jan trip to Balvicar 3

The Final Job List

The trouble with any building project is that as it nears completion the to-do list gets longer and longer. At least with the hull nearly painted we’re very much in the last lap with only a few big jobs left but quite a number of little ones.

There’s one footbrace done and ready to be painted.

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Two more of these are required to complete the set.

There’s a rudder ready to receive its fittings.

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It has a transverse tiller, to which will be attached a fore and aft extension with a universal joint. This should be much more comfortable than what most are using, involving either a bent tiller or a yoke with steering lines. Time will tell whether it works or not.

We lack a trolley, about which see comments at the end of the last post.

Other items may be beyond our ability to make, such as a boat cover and the road trailer.

Jobs list for 17th February

The final parts of the gunwales are on and will be unclamped. The cox’s seat (improved version, not the fairies’) is in as well. Structurally the hull is complete, just over five months since we started laminating parts, and that includes a long break at Christmas and New Year when it was cold and the fairies were drunk and lazy.

Tomorrow it’s more scraping and sanding, sanding, sanding.

And …

Artists of Seil – Stand by for painting duties!

Update late afternoon 17th

Sanding not quite completed today but a cheerful afternoon was had and another couple of hours will see everything ready for painting. Our lovely Seil skiff deserves the best and another session next Sunday will be enough.

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Gunwales still nearly done

This is taking a bit longer than we bargained for, probably because we were rude about the fairies but maybe also because our work at these critical points is highly visible and has to be right.

We had to put the inwales in two stages as we didn’t have sufficient clamps to do the lot at one go and unthinkingly did a complete side first, but it would have been better to glue in two forward or two aft pieces together, as we could have then ensured they fitted each they perfectly. As it was although everything was fine on the dry run we had to re-trim one end of the second side when we came to glue it in, as its partner had slid forward a couple of millimetres.

Now we’re absolutely on the last lap with the external pieces almost ready for glueing. Again the shortage of clamps means one side at a time and we’ll try to get at least the first one done before Sunday, when there will again be plenty to do.

Jobs for 3 February

It’s looking warm enough for gluing, but we’ve had to slice the longer blocks so that they bend without distorting the hull, so they’ll be going in in two stages, the first tomorrow before we leave.

We’ll sort out the pieces for the inwales and cut them to rough length, freeing up stock to chop for the shorter blocks, which we can also glue in.

We can do some filleting round the thwarts to use up any surplus glue.

I suspect the fairies will be back during the week as I’m sure they’re looking forward to spying on the painting tribe, who will soon be in action.

Jobs for Sunday 26 January

Happily the glue went off all right, despite the slightly chilly conditions and also thanks to Nick B’s excellent heater. Of course this just means that from now on there’s absolutely no possible excuse for failing to make progress, no matter how cold or horrid the weather.

In the immediate aftermath of the thwarts going in we need to clean up some (but very few) glue drips, round off the edges of the frame ends to match the main sections that were done earlier and fillet round where the thwarts meet the hull so that everything’s nice for painting.

We need to cut the stem ends to length and shape them with suitable artistry, preferably before taking photos for Scotland Outdoors Magazine.  Iain O’s drawing  has the forward stem cut off three inches above the sheer and the aft one two and a half (as Mother used to say if all else fails read the instructions) and we’ll go with that unless anyone has a better idea.

The next big job is making and fitting the gunwales and breasthooks. We can make a start at marking out where the various bits will go on the hull. A trial bending of the stock today showed that both the Red Meranti and the Dougie Fir are supple enough to take the curve of the sheer without worries.

A really good push over the next couple of weeks will see the hull ready for the painting team.

 

The fairies have been at it again

By this time we all know that there are fairies around the cowshed. On the whole they do more good than harm, sometimes doing a little fairing when the rest of us are away, but one or two of them have been naughty, like the mischievous elf who nicked the end of one of the frames at the very start out of annoyance at all the noise we were making. They have a fondness for pencils, which have been disappearing at a terrible rate, and on Sunday one of them made off with a measuring tape. When it was replaced she did something even worse, casting a spell that temporarily made the new one half an inch shorter, just when the stock for the stroke thwart was being measured. Fortunately we’re up to these bad creatures and the problem has been sorted with two little blocks that will be called dobbies, after the virtuous house-elf.

We’ve now got all four thwarts ready to be fixed in place on Sunday. The glue is currently stored in a nice warm place, so it will mix fine and start to go off, but the temperature is forecast to be so low that it won’t cure this month without help. We’ll need to cover the hull with a canopy and leave a light on inside to keep the temperature from dropping too far.

So, apart from putting on enough fleeces to keep yourself warm, would anyone coming on Sunday please bring along an old dustsheet, blanket or whatever?

Postcript 21 January

All done yesterday and we’ll keep the covers for when we add the winged keel. Thanks to all for lots of hard work and to Betty for the tea and cake.

At least it’s not snowing (yet)

We’ll be back to work today, sorting out the final thwart positions, deciding on the position of the supporting beams and fixings.

The wood for these parts has been machined but will of course benefit from the efforts of our specialist sanders as always.

While  working away we can contemplate our futures as stars of stage and screen. We’ve made a good start, featuring in a major national newspaper and it’s rumoured that the BBC are next in line.