Greenland style paddle – split joint

September 15th, 2014

The arctic people developed their paddles over centuries, but they never had to find space for a 2.3 m long stick in the luggage rack of an overcrowded train. I have been experimenting with various ways of putting a detachable joint in the middle of a wooden paddle.

The conventional way would be to use a cylindrical tube with matching close fitting rod fixed to the other part, and some form of locking mechanism. This has the advantage that the offset between the blade angles can be adjusted, and the disadvantage that a grain of sand can lock the joint unintentionally. However, the Greenland blades are in line.

I have been experimenting with variations on the scarf joint, an ancient technique for connecting timber beams in line by sawing a long diagonal cut in the connecting ends. The problem is to adapt this to repeated connection and separation. The pictures show two methods which work.

First, a one piece paddle is made in a style which I believe originated in the Aleutian Islands. The loom, that is the centre part between the hands, swells to a peak in a plane at right angles to the blade. This thicker central section provides the bulk for a stronger scarf joint. My paddles are made of laminated western red cedar (from standard architectural cladding planks). The reinforced edges are of Paurosa, an African hardwood and the end protection is African Blackwood. Everything is laminated with West System epoxy. However, one could also make a perfectly good paddle from a single plank of Sitka spruce.

While the paddle is under construction, two square rods of hardwood are prepared, about 12 mm square. I used Paurosa from my neighbour Aziz, who deals in African hardwoods, sustainably. Ash would do just as well probably but the tropical woods do not absorb water, while western red cedar does not react much to water, being of very soft constitution. This gives an assembly which does not swell and shrink as the paddle is repeatedly wetted and dried.

Once the paddle is made, two grooves are cut, one on each side, looking at the paddle blade on edge. The groove is barely larger than the hardwood pins. I do not give exact dimensions, because they are not critical; you can judge from the photos, given that the hand grip is the typical 31 x 34 mm oval.

The next step is to saw the paddle in two diagonally, at about 7:1 length to width ratio. The first picture shows the hardwood pin, the groove and the diagonal cut made after the groove has been milled out, or chiselled out if you are patient. I recommend a Japanese saw for the diagonal cut. They cut on the pull stroke and make a clean and narrow cut.

paddle groove and pin

The next picture shows the two pieces cut diagonally. The piece at the bottom shows the pin glued into the groove with epoxy, with two screws to further connect it to the paddle. The upper piece shows how the groove has extended across the cut so that the pin slides into the groove and prevents lateral movement of the ends of the scarf joint. Beyond the end of the groove are two narrow grooves made to take an aluminium channel section, about 12 mm internal size. The pin penetrates into this channel which will prevent opening of the scarf.

glued pin

The next picture is a perspective, showing the aluminium channel in place. It is held by two stainless steel screws and is not glued. This allows for adjustment to give a snug fit to the head of the pin, which has been filed to fit the channel.

channel section

I have added a reflective patch. After all this handwork I do not want to lose the paddle on a night voyage.

The two parts are held together by a stainless steel bolt and self-locking nut. The bolt is set perpendicular to the joint and causes enough friction between the parts that the joint does not slide at all.

For a reserve two part paddle which may need quick assembly on the water far from land I have made an alternative locking system. This is a 3 mm diameter stainless steel staple, It is shown in the picture below holding the two pieces together with both a cross-piece force and also a longitudinal force to keep the pins firmly in the aluminium channels.

staple in place

Notice the third hole to the right. This is a parking place for the staple, to keep it handy and secure.

The next picture shows the staple. Its limbs converge, and so do the brass tubes which it fits into, but the tubes converge less. In this way the staple when pushed in exerts a connecting force but has no tendency to slip back out. The parking tube is also convergent with the other tube on its part of the paddle, but the convergence is greater, so the staple will not slip out, but it will not go so deeply into the tubes before it jams, so it is easy to grasp.

staple exposed

Although I intended this design as an emergency paddle, it has proved utterly reliable, with an insignificant flexibility at the joint, so I tend to use it all the time, which will give me a problem if I need in an emergency to use the bolt connection of the other paddle with gloved fingers stiff with cold. Maybe I will fit a staple system to the other paddle also.

The extra weight of the hardwood and metal bits is around 200 grams. These paddles weigh 1100 grams compared with 900 grams for a professionally made one-piece western red cedar paddle.

There is no patent protection or design protection on this joint – it is an open source design. I cannot imagine it will ever be more than an oddity. But I welcome suggestions for other connection systems. One obvious simplification would be to saw the scarf as a V-section, to prevent lateral movement. Then only a flat metal plate would be needed to stop the joint opening.

Anyway, now I can take the bus to the club boathouse in Dartmouth and go for a paddle. The euro paddle with its two spoons stuck on a rod at an angle to one another is still nearly universal kayak club equipment. But the Greenland style is slowly gaining enthusiasts as its many merits get rediscovered.

The two paddle parts also serve as convenient poles for a low bivouac tarp, or a mosquito net, in Scandinavia and Scotland. The strings will not slide down because of the wedge shape of the scarf. For a higher ridge line, the assembled paddle has a swelling in the middle which also prevents ropes from sliding down. The paddle can also be used as a ridge pole, set between boulders or tied to trees. The aluminium channel can be adapted as a bottle opener. Let me know of other uses.

tim

Dartmouth to Brixham

June 22nd, 2014

The 17 km between Dartmouth and Brixham includes spectacular cliff scenery and varied geology, together with abundant wildlife. On this warm sunny June afternoon we made a promising start in light wind and calm sea. Our destination was Man Sands, a little over half way to Brixham.

Man Sands

We landed on a spacious beach with just one family party enjoying the evening with beach cricket and a barbecue.

drying cairn man sands
(Image by Eugene Craig).

I hastened to use the last rays of sunshine to dry my clothes. The Greenland style paddle is a versatile design, being well suited to jamming into a stone cairn. The other pole is a modern aluminium tube, but I aim to perfect a dividable paddle suited also to holding up bivouacs and clothes lines.

The night started well enough. Then at half past midnight a bunch of youths stumbled by and set up two tents nearby with loud instructions and a tinny ipad adding to the noise. I thumped on the tent to ask for no noise but did not expect any improvement in consideration for other campers, so I grabbed my underlay and sleeping bag and climbed to the top of the hill for a peaceful night under the stars. I think we should not brag about British Values; instead teach courtesy and consideration.

The next day revealed a surprising number of overnight residents of this fairly remote beach. As I climbed down from the hilltop I passed another sparsely equipped elderly bivouaker and politely asked if he was travelling far. That was a mistake since he travelled back in time to his o-level exams, which was the start of a campaign by a malevolent society that resulted in his now being a homeless wanderer. There was also a small tent tucked in round a rocky corner with a couple of seasoned campers who evidently knew accurately the tidal range. As I prepared breakfast with my paddling companion Eugene, a horse appeared with young rider, sedately crossing the sunny beach in the engaging manner of tourist adverts for far off places, such as Ireland. Nevertheless, we decided to blacklist Man Sands as an overnight stop.

Eugene wanted to reach breakfast at the beach cafe in Brixham, before it vanished in favour of the lunch menu. So we started off against a brisk opposing wind, with me fuelled by porridge with strawberries, and Eugene driven mainly by hunger.

basalt sill sharkham

This coast has wonderfully varied geology, nearly continuously exposed in the cliffs. Here, in the stretch west from Sharkham point, a basalt sill has sneaked between the layers of sediment and cooled from the side, maybe by fluids in the zone of weakness now represented by the eroded fissure, so that the cooling cracks developed horizontal hexagonal columns (on the right side of the prominent gully – need to zoom the image).

Eugene at Sharkham

Round the corner of Sharkham point, limestone layers are tilted vertical and crumpled into tight folds. But as one goes west towards the massive reef limestone of Berry Head, the strata become more uniform and gently tilted.

durl head strata

Paddling on beside the dramatic cliffs under the southern fort of the Berry Head defensive architecture, we disturb a flock of guillemots sitting on the water. Their nests are on the cliff above.

guillemots at berry head

This is a high resolution image which just about shows the black backed guillemots standing neatly arranged on the narrow ledges. This is a large colony of birds which only come ashore to breed, so I was sad that we had disturbed them. This nature reserve is exposed to pleasure craft from Brixham. Outside the nesting season, the birds take to the open sea and rock climbers move onto the cliff.

The Berry Head limestone is riddled with caves, inhabited by bats, including the rare greater horseshoe bat, whose roosts here are protected, and also their feeding zones and river valley flypaths. One impressively large cave is accessible from the sea.

berryhead cave deep

There are many other caves which can be explored by narrow boats on calm days. The driftwood branch lodged in this cleft illustrates the variable water level.

narrow cave berry head

A variable water level greeted us as we rounded Berry Head. I had naively assumed that at the neap, the tide race would be easy to penetrate, but the white foaming waves were scary and forced defensive bracing strokes which I have hardly ever needed. The numerous fishing lines deployed from the shore make hugging the shoreline unpopular, further out the wave height increases. The middle route remained rough for much of the way to Brixham breakwater.

Breakfast was still being served at the beach cafe. I had an early lunch of fish pie. We agreed that returning through the raging waters would be unwise with just the two of us. However, our telephone calls for a car to transport us back the short distance to Kingswear went unanswered. A smartphone app showed that we had tackled the tide race at its maximum speed, so that after a leisurely brunch, we might find the sea less intimidating. So it proved. The Berry Head race is the only hazard on this route, in good weather, so we must explore the walking route from St Mary’s bay over to the refreshments of Brixham, and also over the botanical paradise of the nature reserve limestone grassland.

Our return was uneventful, with weak following wind and an opposing tide. The day’s journey of at least 26 km is about my comfort limit as an aging paddler but we took advantage of the slack water through several inner passages along the coast, like this one near Ivy cove.

Ivy cove

tim

Salcombe to Prawle Point

April 13th, 2014

The 5 km stretch of coast between Salcombe north sands and Prawle Point provides varied opportunities for navigating quiet canyons and foaming gaps in the archipelago of bare rock islands. There are sandy beaches at convenient intervals and items of historic interest along the way.

Gara rock lookout

The Gara rock lookout at the top of the slope was used to direct fishermen to shoals of fish. Mercifully out of sight is the recently built hotel, in standard Kingsbridge holiday style with stumpy round towers, no doubt claimed in the planning application to echo the form of the ancient lookout.

Deckler's Island iron mine

Near Deckler’s Island are the remains of a short lived iron mine from the nineteenth century. The grassed over waste tip can be seen on the hillside. Ships used to tie up against the rock on the left of the picture. It is a very exposed mooring so it wasn’t long before a storm put an end to the entire enterprise.

Prawle rock garden

There are many hidden passages parallel to the cliff, broken by gaps to the open sea where the swell bursts through with menacing swirls of rushing water. It is wonderful white water practice, without the bother of swapping car keys to get back to the starting point.

Prawle point

Prawle point also is an island, with a narrow passage which avoids the relatively mild tide race outside. This is the most southerly point of Devon.

Prawle point arch

Just to the east of Prawle point is an impressive arch, beyond which the coast continues as a rocky maze of channels with a low coastal plain behind, backed by the cliffs of an ancient shoreline.

Increasing wind put us off venturing further. Heading back to Salcombe, we stop off for an ice cream at the old lifeboat house on south beach. The motor driven quay heads out to meet the ferry to Salcombe town.

Salcombe south beach pier

It’s a busy day so it takes a while to move passengers both ways without mishap.

Salcombe ferry

A good day on the water, and the car park ticket machine was broken, so we returned home with a few coins.

tim

Dog day at Blackpool

March 16th, 2014

Tide, wind and sun persuaded us that lunch at Blackpool sands was the destination. But we had not checked the Dartmouth district entertainment schedule.

Our mid morning break was at Western Combe cove, which has been entirely cleared of sand by the winter storms.

western combe cove

But the narrow steps up to the coast path were still intact.

western combe steps

Then on under the cliffs to Blackpool, with the rocky contours picked out by the bright March sun.

Our destination was full of dogs, enjoying their last weekend of access to the beach with a ceremony of some sort, where the barking of the dogs was vastly overpowered by the voice of the master of ceremonies, borne by the wind half way back over the sea to Dartmouth. So we queued for our refreshment and then retreated to the steep shingle shore to listen to the repeated sharp grating of the pebbles under the bursting waves, so unforgettably described by Matthew Arnold in ‘Dover Beach’.

blackpool sands

tim p

Farewell to a National Trust sea mark

March 9th, 2014

The little concrete bathing hut at Coleton Fishacre is no more. Another bit of early 20th century architecture destroyed by the waves.

Coleton fishacre bathing hut RIP

That did not stop Alex taking a brief dip in the 9C water. With a resistant relic of the old jetty in the background.

She wasn’t the only mammal in the water. Our young extrovert friend Euston seal made a welcome reappearance after many months.

Photo by Alex Watson

Then we nosed into the cave at Pudcombe cove.

Pudcombe cove cave

The metre high swell gave a pleasant lilt to our paddling and some zest to weaving between the rocks. Our lunch stop was at Scabbacombe.

scabbacombe

Photo: David Jones

The sunshine became hazy as we returned to port after a wonderful spring day on the water.

Scabbacombe head

Tim

After the storm

February 16th, 2014

A rare day of quiet breeze and bright sun tempted us out of Dartmouth harbour and then west along the coast. The storm had refashioned the coastline quite dramatically and the abundant recent rain added extra drama. A fine waterfall descended into Shiglehill Cove.

shiglehill cove

Much sand had been washed away, so it was a bumpy landing for our morning break.

tim at shiglehill cove

The most serious casualty of the storm on our route is the bridge which took the coast path over a narrow canyon. It appears in the previous post, but now only the concrete foundation block remains.

Eugene at the vanished bridge

Returning past Dartmouth castle, the force of the storm is shown by the twisted remains of the lead rainwater pipe.

dartmouth caste rain drain

Even in the harbour there was considerable damage to the walls. The clouds were gathering again as we went ashore by the higher ferry. Next day, the rain resumed.

tim

Rough landing at Compass Cove

December 26th, 2013

Boxing day gave a rare glimpse of sunshine and calm sea. But the heavy swell of past storms gave a whooshing ride through the narrow gap in the rocks in Castle Cove. We led our Danish guest into the shallow cavern below the coast path. It was unusually turbulent, hence the camera shake, and booming with the explosion of compressed air from the swell bursting in the neighbouring inlet.

coast path bridge

Then we moved on to Compass Cove for a mid morning break. The swell caught me by surprise and rolled me onto the beach with some gusto.

tims selfie

My companions persuaded me that a selfie would give a suitably maritime decoration to this post.

Brian and Eugene at Compass Cove

They had landed without rotational acrobatics and were breaking out their refreshments.

Then we paddled over to the Mew stone and poked our noses into the bay leading to Coleton Fishacre but the freshening wind, the long row of cumulus clouds on the western horizon and the veiling of the sky with high cirrus persuaded us that it would be wise to return.

Brian and Eugene in Mill Bay Cove

We paused in the safe haven of Mill Bay Cove, poking our noses into the cave but withdrawing as surf crashed into the other entrance. Our lunch pause under the tower folly was warmed by the weak sun reflecting from the stone. We sat on the recently installed defensive gabions, which look impermanent, but time will tell.

We paddled back between the castles with the low winter sun lighting the leafless trees above Dartmouth castle and the exotic pines above Kingswear castle.

harbour entrance

As we paddled up river to the higher ferry the high cloud thickened and the sun disappeared behind the gathering storm. It was a rare day of sun and calm between the series of winter storms.

tim