Monthly Archives: April 2018

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.

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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.