Frequently asked questions
How do I decide which model and variations to choose?
Vember is designed as a responsive rough water day-paddling kayak, and Vembex is the lengthened version for extra load capacity for expedition use. One can also vary the scale of the plans to suit your bodyweight, as determined by the graph below under “Will Vember work for my weight?” Finally, select your desired height for leg clearance at the front of the cockpit, between the keel and bottom of the cockpit rim. Experience in other kayaks will guide you in this.
Will Vember work for my weight?
As described in the free downloadable Build Manual, the height of the gunwales can be varied to suit differing paddler and equipment loads. However, the scale of the plans can also be changed during printing, so that every dimension of the kayak is adjusted by the same percentage. Below is the graph we use to relate the printer/plotter percentage scale to various loads of paddler plus equipment, in pounds. (For Vembex you can safely add 64 pounds to the load on the x-axis, as shown in the photos in the Build Manual)
Because of the length limitations in the pdf specification when using the continuous roll print option, the pdf is downloaded at 25% scale, so percentages taken from the above graph must be quadrupled. For example, a load of 137 pounds (62.1 kg) suggests a 90% plot, quadrupled to 360% at the printer if the pdf is downloaded at 25%. Feel free to experiment with your planned design. Bear in mind when scaling the design that all linear dimensions must be changed to the same scale. That includes all the measurements relative to the datum line, such as paddler seat centre, position of temporary forms (exterior and interior), and position of bulkheads.
How do I know that my plans are printed accurately?
The plans include two lines, each 100 mm long, one along and one across the print-outs. These lengths should be checked with a steel rule to ensure accuracy. Our comfort level is plus or minus 0.5 mm.
Should I use cove and bead or rectangular section timber?
As mentioned in the Build Manual, using pre-shaped cove and bead timber is a fast and simple way to produce the hull, and the cove retains the glue for much of the construction. As Vember was my first attempt at strip-building I decided to use this method. However, an alternative method is to use rectangular section 19 mm x 6 mm timber without milling for cove and bead. Each strip is hand-planed on one edge as it is test-fitted into place before gluing. This will take more time and patience, but can be a lower cost option. A detailed discussion of this and the use of thinner strips (4.5 mm/3/16th inch) may be found at the laughingloon website.
Should I use stapled or clamped construction?
I chose to use clamps as I didn’t want the staple holes and I didn’t want the tedious task of removing staples. However, there are simple ways to deal with these issues. Moreover, clamping obstructs the next strip position, so I only fitted a pair of strips each day (one on each side.) I could have fitted one pair in the morning, and another pair in the evening, but I was in no hurry. Using staples to enable continuous stripping may be desirable for professionals, but, as a beginner, I was using half-length strips to make the fitting of the tapered ends less critical. This then requires at least a butt-joint part-way along the hull. The simplest way to ensure this joint is fair is to clamp it, again obstructing placing of the next strip. There are ways around this, perhaps using super-glue or hot glue, but I wanted a simple fool-proof method, and clamping worked for me. Stripping the hull is very enjoyable, exciting and rewarding. I took my time.
How strong is the hull?
The timber core, surrounded by inner and outer layers of epoxy and glass cloth forms a composite structure of remarkable strength. I removed a strip of Vember’s hull for the skeg slot, and I was unable to snap it in my hands. Here’s a report from Damian, who thought he’d wrecked his Vember Expedition:
“The composite construction is incredibly strong. On a recent outing, I was carrying my Vember Expedition across a rocky shore and completely failed to spot a knee-height boulder. When I tripped over it, I flew forward and ended up crashing down on some sharp granite rocks with my full bodyweight on top of the boat. If you wanted to smash a boat in one manoeuvre, this is how you’d go about it – a plywood boat would have been garden-waste-sack-material, and I reckon it could have holed a fibreglass boat. However, the composite sandwich construction laughed it off – the only damage was a few patches with little white ‘brickwork’ patterns, where the fibreglass had delaminated along joins between wood strips. It paddled back fine, and was completely dry.
Repairing this kind of damage is actually very easy – it’s just a matter of sanding away any damaged fibreglass, and replacing it with a fibreglass patch which overlaps the existing glass. By ‘feathering in’ this patch with sandpaper and then re-coating with epoxy/varnish, the repair becomes invisible.”
Does Vember need the skeg?
Whether or not a skeg is necessary very much depends on the area you paddle, what are the wind and sea conditions in which you paddle, and your own physical state. For example, Nick has a chronically damaged right shoulder. He can’t afford to edge and sweep for long periods to counteract weather-cocking. The worst conditions for weather-cocking are flat sea and strong winds from the quarter. If you always aim to paddle in light winds, and you are fit and strong, then you may never need to deploy a skeg in a well balanced kayak. If you are in doubt, you can build a Vember without a skeg, but with a stern hatch and the stiffening structure for a skeg. You could then retro-fit a skeg if you decide one is desirable, although this is more awkward than fitting one during the initial construction. In the end though, we have not yet paddled a sea kayak that, ultimately, and in certain conditions, did not benefit from the deployment of a skeg.
Can I omit sheer clamps, and rely on glass tape inside and outside the deck to hull joint?
We strongly advise against this. The sheer clamps produce fair smooth curves and enable a very strong joint. We’ve spent too much time mending these joints on $3000 glass fibre kayaks where glass tape has been the sole method of joining the hull and deck.
Can I use cheaper plywood for the deck?
The recommended BSS 1088 3mm okoume plywood is usually of superb quality. It is consistent in that we have experienced no voids in the inner ply, and it bends evenly without splitting. We have experimented with cheaper plywood, with conspicuous lack of success.
What brand deck hatches do you use?
In the U.K, SeaWorld and Barton hatches have proven to be 100% watertight, as claimed:
The screw threads must be kept clean, and a smear of silicon grease on the sealing rings will help keep out any water.
Can I get the CAD DWG or DXF files?
The Vember templates were drawn using QCad. The original CAD (DWG and DXF) files are included in the plan and template download file that you can receive using the download page. We encourage you to alter, enhance, experiment and improve upon every aspect of our work. If you want to make money making kits and selling them, or constructing kayaks derived from this work you are free to do so.
What CAD system and file specification was used to produce the Vember plans?
QCAD v. 3.16.4, an open source program, saving DXF and DWG files in R27 (2013) format.
I have put the Vember form plans into a 3D CAD sytem, and the keel and other lines are not fair curves. Is there a reason for this?
From Nick Crowhurst:
I do not design kayaks on a CAD sytem, even though that would be a comparatively quick procedure. I build a wooden prototype hull by eye over a period of weeks, continually modifying the forms until I am satisfied with the shape. I then take hundreds of measurements and input these into a 2D CAD system so that I can put the forms plans online for the world. This is a cumbersome and time-consuming process, prone to inaccuracies. However, my aim is to produce a work of art that paddles beautifully. Limiting the shape to that which pleases a computer program is unacceptable to me.
CAD systems use a variety of algorithms to produce a curve from a series of points. Some produce the best-fit curve that goes through the points. Others produce a smooth curve which does not necessarily go through the points, but smooths out the curve in a way that satisfies the relevant algorithm. In QCad, for example, one can choose “spline-fit points” or “spline-control points”.
Because of all the potential for accumulative error in producing the framework of forms, shims should be used where necessary, as described in the Build Manual. I sometimes use small pieces of greetings card to pack out a junction between a form and a strip. Wood is not a synthetic material, and each strip will have its own bending characteristic. If my measurements are within + or – 1mm, then I am content. For example, my plywood work-top has a slight dip about half way along one side. I shim one end of the adjacent form with a steel washer.
The Vembers built to the forms have elegant curves and perform as desired.
Why the name Vember?
Vember, like Shrike, is the name of an extreme rock climb on Clogwyn d’ur Arddu, a cliff on the north face of Yr Wyddfa, the highest peak in Wales. Vember is also a girl’s name in Wales. More particularly, “a vember” has recently come to mean “an adrenaline rush”.
Why the name CNC Kayaks?
We like to play with words. CNC is, of course, widely used as an abbreviation for “Computer Numerically Controlled”, which describes the method by which computers take over from humans in much of industry. We design our kayaks by hand and eye, rather than be constrained by the limitations built into the controlling software. We only use a computer to receive the manual measurements of the completed kayak, and output these measurements to plans. So, CNC is used tongue-in-cheek, knowing that it is likely to be misinterpreted. The truth is that Christopher & Nick Crowhurst is the reason for the label.
How many hours does it take to build a Vember?
Obviously this depends on one’s experience but an estimate, including some thinking and reading time, would be 150 hours for a first-time strip builder.