C2 compared with Duet

I’ve compared the new C2 with The Darkness C1 because that was the starting point for the design however, to get a proper C2 perspective, I should compare it with The darkness Duet C2.

So I laid them side by side and took some pictures and measurements.

Duet and new C2 – 1.

The Duet conforms to a continuous arc from bow to stern, whereas the C2 has a long section of parallel width. The Duet was designed by a Naval Architect using CAD tools and fluid dynamic algorithms, The C2 was pretty much guessed at.

Key dimensions are:

Max width at the gunwales: Duet – 68 cms, C2 – 56 cms
Boat depth from hull to central thwart: Duet – 27 cms, C2 – 28 cms
Boat depth at rear of cockpit: Duet – 26 cms, C2 – 29 cms
Boat depth at front of cockpit: Duet – 34 cms, C2 – 29 cms
Seat height: Duet – 20 cms, C2 – 15 cms.

Weight: Duet – 21 kgs, C2 – 18 kgs.

Duet v new C2 – 2

The weight comparison is a bit of a red herring as the C2 has the additional seat adjustment rails but would benefit from some additional stiffness within the laminate, but 18 kgs would seem about right.

This particular Duet is not really representative either as it’s based on two layers of carbon, hence the additional stiffening across the hull. Without the now standard internal layer of Kevlar it is more vulnerable to damage. A more realistic weight with the Kevlar would be about 23 kgs. This boat also has some seat rails because as the demo boat, it needs to be more adjustable. Adjustments for the rear paddler is serviced by moving the footrest.

Duet v new C2 – hulls

As both boats are ICF compliant, the only difference in the hulls is the cross section profile. The C2 is much slimmer but water resistance is usually measured by the wetted area. The Duet will support a heavier payload and is massively stable, but it would be interesting to measure the wetted area when paddled by two racing snakes.

Duet v new C2 – cockpits

The C2 cockpit has less open space but at 310 cms, it is still greater than the ICF 280 cm minimum spec. I’ve positioned the seats closer together to take advantage of the central buoyancy. As the boat tracks so well, it isn’t necessary to have the rear paddler way back towards the stern. Also, we don’t need to leave the central area available for camping kit and the like.

I’ve set the seat height for the C2 at 15 cms. This is 5 cms lower than the Duet because I’m expecting it to be less stable.

Duet v new C2 – front and rear decks

The front deck has lost the steep gradient and the ridge. This should make it more comfortable for portaging, but there may be more water coming across the deck in rough water.

Notice also the lack of a name, what on earth I am going to call it? Dual, Duo, Double, Dunno!

Duet v new C2 – bow and stern

The C2 is closest to the camera and it shows that the Duet has less height in both the bow and stern areas. It will be interesting to observe the freeboard, and how much will be sticking out of the water (and likely to catch the wind). I’ll also test the curved bow.

Tomorrow I get to test it, and the day after a Duet crew has agreed to give it a go.

First prototype

The first boat came out of the mold last week and I collected it from Devon. We’d had a number of discussions regarding the construction and I was adamant that the boat had to be light, and the prototype was the right time to take a risk. We agreed on a 200 gram carbon twill supplemented with a 200 gram Caron/Kevlar weave. We knew this would not be stiff enough so we implemented a series of uni-direction cross members. These in conjunction with the flanges, would form a sort of scaffolding……………..or at least that was the theory.

The boat came out of the mold weighing 12 kgs. This was crazily far too light for a C2. However the construction seemed to work, with the right kind of stiffness but with some flexibility to absorb knocks. However we hadn’t continued either the flanges or the cross bracing beyond the boundaries of the cockpit, so the deck and hull in the stern and bow areas are a tad flimsy. That will be rectified on further boats and may add another kilogram.

As the design is based on The Darkness C1, I immediately compared the two, yep, completely different! The front deck especially, has lost its sharp gradient and ridge. The gunwale edge remains which adds lateral rigidity and supports the full length spray deck.

The C2 (I must think of a name for it) has a constant cross beam at the gunwale of 55 cms, The C1 has a maximum width of 51 cms.

Comparing the C1 and the new C2 – decks

The hull seems to have more curvature than the C1.

Comparing hulls

The array of different materials is starting to grow on me but I’ve never been a fan of Kevlar. We do need it though to give the boat some strength.

The boat is actually quite deep. I added on 10 cms of deck height from the C1 to increase the freeboard. The boat will sit lower in the water and it will interesting to see what level of payload it can support.

Birds-eye and side views.

It took a couple of days to fit it out with seats, footrests, thwarts, portage handles and buoyancy.

Fit out complete.

I took advantage of the parallel flanges to mount the seats on rails. These enable a high degree of adjustment which will allow many people of different shapes and sizes to easily and quickly change the setup. These will be discarded for a racing setup as they add over 1.5 kgs to the weight and I do lose some rigidity across the width.

Cockpit arrangement.

I’ve added the usual grip tape the assist non-slip getting in and out. The thwarts are positioned to provide a stable hand hold during embarkation. I will be putting some cycle handlebar tape in the centre to improve grip and comfort.

Rear seat on sliders.

The seats are to my own design, similar to racing kayak seats but with a much bigger seat pan. This adds comfort and better stability. They are currently set at 15 cms high which is 5 cms lower than the Duet.

Front seat setup.

The footrests support the pull bars which have proven very successful in The Darkness Duet C2, and the footplates have grip tape on them.

Bow and stern.

The bow is more curved to help avoid picking up weed.

The handles are my own design and made of carbon. They are similar to the Marsport handles, but shorter, lower profile and have a deeper recess to support a torch. I’ve mounted plastic tubes wrapped with cycle handle bar tape for better grip, comfort and warmth in lieu of a torch.

So, it’s all over bar the paddling.

I’m looking forward to its maiden voyage and subsequent experimenting with the setup, and then I’m hoping a few crews will try it out.

We have a mold

The plug was rubbed down and polished in preparation for the construction of the mold. The black top coat was applied on top of a pink sort of undercoat. This would help indicate where the rubbing down was getting too much as the pink would start to show through.

Front deck

I must admit that pink on black does look pretty cool, but no, it will not feature on a finished boat.

The shallow trough feature at the front of the cockpit does give an otherwise featureless front deck a little bit of character. Any water travelling along the deck should be channelled around the cockpit edge. If there is any risk of rough water, it is expected that a full spray deck will be fitted.

Front deck drain trough

The rear deck mirrors the front in that it is flat and feature less.

Rear deck

However the shallow trough at the front has be replicated at the rear. This does not really have any practical application, but it looks nice.

The plug is pretty much redundant once the mold has been constructed and is usually thrown away, but it has cost me £1,800 to get to this stage so it is safely stored away. It is also my insurance if I need to make a new mold.

Another £1,000 gets you a mold. The last stage before an actual boat can be made. The plug remained in the mold for a week to ensure an accurate facsimile and no movement when the fibre glass was still “green”.

The mold

All the time taken to achieve a smooth finish has paid dividends on the mold. This will deliver a smooth finish on the boat, and ensure that the mold does not stick to the gelcoat.

The cockpit

We’ve created wide flanges to help form an accurate and consistent join.

Mold flanges

All the hard edges have been eradicated on this boat to help the carbon form in the curves, thus reducing the risk of trapped air pockets.

In a few weeks’ time the first boat will pop out of the mold, and the maiden voyage will be the moment of truth when I’ll know if it meets my expectations. This time the design is based more on gut feel rather than my trusty Naval Architect with his CAD, 3D modelling and fluid dynamics algorithms. I’m quietly confident that it will deliver an increase of speed compared with the Duet, albeit with some trade-off in stability and payload capacity.

I also have some ideas for construction. I’m planning a layer of carbon fibre on the outside, supplemented with a layer of carbon-kevlar on the inside. This has proved not to be rigid enough on the Duet, but I’m going to use additional ribs at regular intervals from stern to bow which in conjunction with the full cockpit length flange, should form a rigid framework.

I’m looking forward to an interesting summer putting the boat through its paces.

New C2 – plug progress

I had built up the height of the deck on the new boat because I was concerned about the amount of freeboard on the boat. So I starting taking more interest in the K2 designs and was surprised just how close to the edge some of the designs are.

K2 freeboard example

This was particularly illustrated by photographs from the Thameside II race where the water was quite choppy. The K2 decks weren’t swamped but the low level certainly necessitated spray decks. This did however reduce the profile above the water line which was beneficial in the strong head wind that day.

Contrast this with the amount of freeboard on the Wenonah ICF.

Wenonah ICF freeboard

All of the boat surfaces above the waterline are subjected to the influence of the wind. This deep design is necessary due to the fully open cockpit area, and the risk of swapping.

Meanwhile, progress on the new C2 design plug is moving ahead.

Top: treat all timescales from boat builders with a huge pinch of salt!

To be fair, they have put in a huge amount of work, taking my rather crude model and refining it towards something far more superior.

The first task was to cover it with a thick layer of filler.

This helped get a good idea of the final shape and provide a base for finer shaping. We wanted to avoid shape edges, but these were kept until the end so we could see the symmetry.

The groove for the spray deck was made deeper so that the tops of the gunwales would not be wider that the boat.

The weight of the additional filler caused the boat to bow. A long piece of timber was secured within the hold to add strength, and a strip of foam was secured to the hull to show where the new level was. Even more filler was added to fill the bend.

Gradually the shape was built up to eliminate any rocker throughout the length of the hull. This would ensure the true and straight tracking which was witnessed during testing of the early prototype.

Once the shape was defined, additional layers of finer filler were applied.

I kept the transom shape of the stern which is a distinctive feature of DarkSide canoe designs. The rear deck is flat, and the sharp edges have now been rounded.

The rounded edges makes manufacturing with carbon easier as it is not required to bend into angles which risk trapped air pockets.

The front deck is also flat. It won’t shed water as quickly as a steep design, but it will be more comfortable to portage upside down on the shoulder, and easier to mount handles and lights.

The hull is also complete.

The boat is ten centimetres narrower than The Darkness Duet and only two centimetres wider than The Darkness at the widest point.

The rim along the top of the gunwale is retained. Again, another feature of my boats and key to support the full length spray deck.

Two final coats of resin were applied ready for the last rubbing down and polishing in preparation to make the mold.

It does look nice with a gloss black finish, but it will be manufactured in raw carbon with a layer of carbon/Kevlar. I have some ideas regarding the construction which will ensure a light, strong and rigid boat.

It’s almost temping to jump in and paddle it now, but I’m confident the wait will be worth it.

Onwards to the mold.

New model C2

With a bit of spare time on my hands and a couple of days without rain, I decided to crack on with re-designing the new C2. A couple of outings on the water demonstrated a significantly quicker boat, reasonably stable, but in need of more freeboard. It certainly maintains a direct line as it’s so straight and skinny.

The water was lapping towards the top of the gunwales and the bow was only just above the water, it was almost a stealth canoe!

There was also far too much open cockpit because it was based on the C1.

So, I cut off the top of the gunwale and secured some 100mm insulation foam to the top. I glued some 60mm foam on the deck areas and set about it with some course sand paper. The ICF rules state that the cockpit must be at least 2.8 metres long, I’ve made mine 3 metres long just to make sure. Even so, the length of the rear deck is quite long at 175cms and the front deck is 162cms.

This does mean that the rear paddler is not traditionally positioned right in the stern.

The new boat in profile

At this stage, I had a completely blank canvas and could have carved any sort of flamboyant and intricate design, but I wanted the boat to be a no-nonsense flat-water racing machine. I also wanted to make it easier, quicker and cheaper to make, so I avoided corners and acute angles.

Starting with the front deck, I made it as flat and created rounded sides. The flat deck makes it easier to mount a handle and lights, plus it is more comfortable to portage. OK, if the bow “disappears” on say the Henley Straight on a windy day the front paddler may get a bit wet, but they’ll have the spray deck, and I’m in the back anyway!

Front deck design

The front of the gunwale which supports the spray deck will be lower than the front deck. I’ve planned some side channels to drain any water, but it’s also more aerodynamic as the top of the front gunwale is not too high. OK it’s not a massive advantage, but “marginal gains” count, as “Sir Dave” would say.

The bow will be curved to ensure that it does not catch weeds or leaves. Hopefully I won’t need the ACME coat hanger weed deflector on this boat.

The philosophy behind rear deck design is similar to the front, flat deck and rounded sides.

Rear deck design

I’ve also kept the iconic transom stern which is perhaps a trade mark of DarkSide Canoes. It’s massively cock-eyed at the moment, but I have faith in my boat builder to sort it out.

Gunwale and cockpit

Using a broom handle wrapped in course sand paper, I formed the gunwale and spray deck recess. I filled the space between the insulation foam and the existing deck with expanding foam gap filler. It’s not perfect, but again when my boat builder has stopped laughing, they’ll sort it all out. I want the recess a bit deeper so that the side of the boat is wider than the gunwale, however it can’t be more than 5cms in towards the cockpit to ensure ICF compliance. The maximum boat width will be 55cms.

Additional freeboard height

The plug is now with the boat builders and I hope to have a faired shape this week, and a mold not long after.

I’m looking forward to paddling this boat and I’m hoping the slimmer profile will appeal to racing kayakers.

Sliding Seat

I’ve sometimes wondered about the potential benefit of a sliding seat in a canoe, especially when I’m on a rowing machine. As an advocate of the longer paddle stroke, a sliding seat would enable the catch to be further forward, the use of the legs during the power phase, and a delayed exit as the blade would remain in line with the hips for longer. I can’t think why it hasn’t been tried before. I expect it has, but I can’t find any references other than some anecdotal citations.

Whilst I’m developing the new skinny C2, I have a boat which is much more suited to a sliding seat. Due to its length, it will be less prone to rocking as the paddler’s weight is continually transferred fore and aft.

So, the first challenge is mount the seat on some sort of rollers or wheels. A quick look around the garage (full of “useful” stuff) , I discovered some rollers we’d used to make shifting the washing machine a bit easier.

Perfect, I’ll just shorten the wheel base an bolt a seat on.

Seat mounted on wheels

The underside

So far, so good. I now needed a captive rail enclosure in which the seat could roll back and forth and maintain a fixed path.

So I knocked a sort of box up out of timber. The weight and aesthetics didn’t really matter, it was just the concept I wanted to test. Early dry land testing quickly revealed that it wouldn’t work the way I’d imagined. Most of the wheels didn’t touch the ground and it kept “crashing” into the sides of the box and getting stuck. I even cut off the surplus wheel sets, but it still wouldn’t track.

Sliding seat in captive track

I started to look on the internet for the sort of thing used by rowers. As racing rowing boats are hideously expensive, I didn’t expect the seat system to be cheap. Turns out it was less than £100.

I got the wheel platform and rails from a place in Chertsey. (https://shop.carldouglas.co.uk/) I had a long chat with Charles Douglas (the owner). He knew a lot about canoeing and the DW. I think he said he’d done the race and the results show a C Douglas completed the race in 1988.

Rowing boat sliding seat kit

I mounted the seat on the wheel assembly and then constructed a frame for the rails. I wanted to get it as low as possible as I didn’t know how stable it would all be.

Seat mounted on the undercarriage

The motion is so smooth.

Rails set parrallel within a frame

Them I secured into the boat. This was fairly easy because the boat has a long length of parallel sides plus the flange is also the whole length of the cockpit.

Sliding seat system in the boat.

The pull bar on the footrest was essential for securing the feet.

All setup and ready to go

I took it for a quick test on the Kennet at Newbury and it was surprising stable and easy to use. This was a good job as I’d entered the Basingstoke Canal Challenge the next weekend. This is a 16.6 mile there-and-back event with only two portages (one out and one back) so the 21 kgs weight of the boat should not be too much of a factor.

What could possibly go wrong?

On the way to the start, the seat cushioning came away from the seat and it’s somewhere on the M3. Usually the car is chocha-block with spare bits of foam, but not on this occasion.

So I lined up for an early start with a C2 crew who seemed hell bent on a sprint start. I managed to drop them quite early and settled in to a good rhythm. A couple of times I got out of sync, and on occasions I got no benefit from the sliding seat as I did not phase the stroke right and was simply going forwards and backwards. However when it did come right, it felt good. The key seemed to be to delay the slide until after the catch, and not before.

Unfortunately the additional weight of the boat and the drag effect did not deliver a particularly fast performance by the time I got to the portage.

Twenty one kilograms on your own is quite a hefty weight. The portage was slow, but I huffed and puffed to the put-in and headed for the turn.

At the eight mile turn I was getting tired, and decided to lift the boat out for a rest.

On the way back to the portage things started to deteriorate. My back hurt and I was gradually adopting a lent back position. Even by exaggerating bending forward for the catch, I could not compensate for it.

I got back to the portage, lifted the boat out and put it down. Then for some strange reason I started walking backwards, I just couldn’t help it. My body seemed to have forgotten its correct upright position and off I went until I fell over.

After a stern word with myself I managed to get the boat to the put-in. As I moved towards the canal, I fell over again with the boat on top of me. A young girl, part of a K2 crew has also reached the put-in, she looked down at me and asked “would you like me to help you up?” and one handed, she hauled me to my feet. I thought this would be a good time to quit, and did.

So it was a bit inconclusive. I’m convinced that it is worth trying again with a lighter boat and a shorter distance, but ot’ll have to wait because the boat is back to a C2.

C2 extended – Take II

I’ve reset the seats now to something more sensible! I don’t know why I set them so close together. Trouble is, when you’re on your own, there’s no one to tell you when you’re being silly.

Anyway, hopefully the boat should be trimmed better this time.

Rear seat set further back

When compared with the Duet and the previous setting, my mistake is more obvious.

Duet, first attempt, modified position

Not sure that I can go much further back due to lack of buoyancy in the stern.

I also took the opportunity to change the shape of the bow. I’ve used a coat-hanger leaf clearer during autumn when the canal turns to soup due to all the leaves.

The original shape picks up the smallest leaf and takes some bouncing to get it off. I’ve now replicated the curve on the actual boat, it remains to be seen if I’ve got the curve shallow enough.

Modify bow profile

It doesn’t look very pretty though. Wonder if it will work?