Sea kayak safety performance
The reports and other material listed
here explore buoyancy design in kayaks used on the sea and open water
along with the ability of the crew to control their craft after mishap.
of this material pre-dates the internet and most have never been
published in any other media and never collected together before. As
kayaking on the sea becomes increasingly popular, this information is
intended to increase awareness about the importance of buoyancy.
It also illustrates how basic design can be improved to increase the
Is your kayak capable of the above? Can it sink at one end if flooded? Can it sink altogether? Why?
In 1980 a new sea kayak (now not in production) was introduced to the UK market. It had solid foam buoyancy at each end, a Minimum Volume Cockpit of 95 litres volume and a confluent hull space separate from the cockpit.
These three features confer a superior safety performance compared with conventional kayaks manufactured with bulkheads and no solid buoyancy that are commonly available up to the present in 2013. This safety performance follows some simple physics. It has been demonstrated by experimentation and several reported incidents tend to support the predicted outcome.
During the 1980s and 1990s some key members of the UK kayak trade opposed the new design. As a result the advantages of the new buoyancy design were not promoted and test reports were not properly publicised.
The links below lead to those test reports and others.
In addition are included a simple kayak flooding test indicating ease of recovery from a capsize and kayak volume statistics compiled from a variety of sources.
This collection of information concerns only recovery (self-rescue) by kayakers. Rescue by the assistance of outside agencies such as Coast Guard or lifeboats is not considered in the material here. The focus is on increasing self-reliance by improving both control and the recovery of control by better buoyancy design.
Some other terms used in the following may be unfamiliar: primary and secondary buoyancy, paddled and safety performance.
Primary vs Secondary buoyancy
Primary Buoyancy is that which operates when the craft’s seating position (the non-buoyant part) is swamped through capsize or waves. Secondary Buoyancy is that which operates when the Primary Buoyancy is compromised by hull damage or malfunctioning hatches. In decked kayaks Primary Buoyancy should be a maximum and Secondary Buoyancy must be solid.
Safety vs Paddled performance
Performance of kayaks can be conceptually subdivided into paddled performance and safety performance. Paddled performance concerns how the craft behaves in waves, how fast the hull shape is for example. Safety performance is about how easily the craft can be recovered from mishap such as capsize or damage or other malfunction. There is some overlap, for example in respect of directional control, but the separation is a useful concept when considering recovery from mishap.
Please note the links below are to PDF files, some of which are large. File size, numbers of pages and photographs are listed in each link. PDF files are best saved first then viewed in Adobe Reader, a free program (http://get.adobe.com/uk/reader/). The Lamont and Winning reports have many photographs that are internally linked to the text references. In Adobe Reader the relevant photograph can be viewed from the link in the text. A green ‘return’ button on the bottom menu bar will take the reader back to the same place in the text.
Test reports and other references
Prevalent attitudes to safety in the canoeing and kayak world rightly focus on training and personal equipment. Little seems to have been written about the possibility of improvements in the buoyancy design of the basic craft itself. This article challenges attitudes to the subject with special reference to published accounts of kayak incidents, in particular Deep Trouble: Stories and Their Lessons from Sea Kayaker Magazine.
This report was submitted to the Director of Coaching, British Canoe Union in September 1989 but remains unpublished. The report covers the progressive flooding of two kayaks in flat water: one with two bulkheads and no secondary buoyancy and another with solid secondary end buoyancy, a confluent (continuous) hull space and minimum volume cockpit (MVC). Internal links between text and photographs can be used when viewed in Adobe Reader.
Winning, DR, OBE, (1990), Sea Tiger Report: Report on comparative tests of “Sea Tiger” sea kayak and other sea kayaks on behalf of the British Canoe Union
This report was submitted to Director of Coaching, British Canoe
Union, October 1990, but remained unpublished (although photocopies
could be obtained, on request, at least up to 2007). The PDF version
here has been transcribed from the original hand written version and
reformatted. Units of measurement have been converted to SI: litres and
kilograms. The report and testing was not supported by the
manufacturing trade except by Sea Tiger UK. No magazine, nor the British Canoe Union can publish this report.
Padwick, N, & Atkinson, M, (1988), Incident report and results of subsequent investigations,
Circulated privately by Sea Tiger UK, this investigation was carried out after a seminal incident in 1988 where a paddler in a leaking kayak became effectively immobile in large waves and high wind off Anglesey, Wales. The weight of water in the kayak made progress impossible and the paddler was eventually rescued by a helicopter. As a result of the incident a method of emptying hull water from the confluent hull kayak was discovered and this became known as the ‘Hatches off Rescue‘. This method was later validated by Winning and included in his 1990 report (p16). No such method exists for emptying water from the compartment of a conventional bulkhead kayak with no solid, secondary buoyancy.
Padwick, N, (1986), The Sea Tiger Handbook
This PDF is a scan of the Sea Tiger handbook supplied with each new
Sea Tiger kayak in which the recovery capabilites of the kayak are
described (the Sea Tiger is no longer in production). No comparable
user manual was ever supplied with any other
UK kayak as far as we are aware .
Carter, PJ, (1991), A kayak flooding experiment
Following the Lamont and Winning reports, Peter Carter duplicated some of the tests and, importantly, extended the testing to a comparative paddled performance over a triangular course in moderate wind with a simulated hull leak. These experiments demonstrate the advantages of a confluent hull.
Gronseth, G, (1993), Saved by a drysuit
The paddler in this story in Sea Kayaker magazine, Summer 1993, Vol 10, No 1, pp34–37, was using a confluent hull kayak that remained controllable with a hull leak for longer than a bulkhead kayak would have been. This had an important bearing on the outcome of the paddler’s ordeal—it was jointly responsible, with his drysuit, for saving his life—but was a vital point not credited in this account in Sea Kayaker. The article cannot be reproduced here for copyright reasons but is outlined in the second example of an incident with an MVC cockpit - see Minimum Volume Cockpit kayaks - 4 Incidents.
Carter, PJ, and Lamont, P, (2004), Cockpit intake test: CIT volume
The CIT measurement is an easy test for any paddler with a bucket and sponge to carry out. It provides an indication of the ease of recovery of a decked kayak and is strongly recommended. The lower the measure the better: below 10 litres is recommended.
[pdf file 225KB, 5 pages with small colour photos] or coauthor’s Web version Cockpit intake test
Minimum Volume Cockpit
kayaks - 4 Incidents
This compilation summarizes
four incidents involving kayaks with minimum volume cockpits (= low CIT
measurement). 1) A hull leak off Angelsey, Wales in 1988 in difficult
conditions; 2) A hull leak followed by a long swim; 3) A crossing of
the Minch, Scotland with a hull leak; 4) A capsize and swim towing the
Lamont, P. (2007), Commercially manufactured volumes
This is a table of kayak volumes collated from various sources (gathered in 2007). It illustrates why paddlers may encounter problems after capsize and exit. Note that, by proportion, a greater volume of a double kayak is non-buoyant compared to a single.
State of the Art?
This one page document was prepared in 2000 for a committee as a
stimulant for discussion. How do the questions apply to your kayak?
Is your kayak the State of whose Art?
[PDF 123KB, 1 page text]
Compilation of all these data, reports and tests owes much to Peter Carter and Alan Byde. All of this started in the first place with the design and development of the "pod" or integrated cockpit for kayaks by Alan Byde in the late 1970's.
About the authors
Peter Lamont: 44 years paddling, including 15 years instructing beginners and novices on multiday expeditions in the waters around the Corryvreckan, Scotland
Peter Carter: 40 years paddling and
instructing and a member of the Australian Canoeing Education and
Safety Technical Committee
Alan Byde: now retired, was one of the first senior BCU Coaches in the early 1960s and has written several books on canoeing and canoe construction