Some Advice On The Types Of Kayaks and Canoes

Here I will try and give some simple advice and guidance on the different types of kayaks and canoes available and their general characteritics for the benefit of typical beginners rather than paddling maestros!  I will cover the sort of boats most beginners will be interested in rather than the specialist types of boat (if you want one of those the you are probably advanced enough to not need this advice).

First The Obligatory Warning - Paddlesports are an incredible way of exploring, having fun and unwinding either in a laid back leisurely fashion or alternatively by paddling in waters and conditions providing the highest excitement and adrenaline rushes (or terror!).  But water can also be very dangerous, or fatal, so always err on the side of caution and never under estimate it.  Be prepared for the conditions, do your research on tides and currents and always paddle within your limitations.  If and when possible get professional training  but if you can't be very careful and make sure help is at hand should you need it.  Strongly flowing rivers or the sea can be very unforgiving places.  Water can produce an incredible force stronger than any human and quite capable of crushing and folding up the strongest kayak or canoe and pinning a paddler under water.  Conditions can change extremely quickly, sometimes within minutes going from flat calm to steep waves just because the tide has changed from going out to coming in or the wind has suddenly picked up or there has been a rainstorm further upstream.  It is recommended you never paddle alone on the sea.  Always wear a buoyancy aid. For your first paddles try to find a still or gently flowing river or lake and make sure someone ashore knows where you are in case assistance is needed.  Having said all that, with a placid water venue, a cautious approach and with the plethora of paddling tutorials available on Youtube these days it is perfectly possible for anyone to get afloat and teach themselves to paddle pretty quickly.

The following are just my views and opinions gleaned over several decades of kayaking and canoeing experience and even for a time working for a canoe and kayak supplier which allowed me to see and test quite a wide range of paddle craft in addition to the numerous kayaks and canoes I have personally owned so I have gone through the journey that many beginner paddlers will undertake.  I also have many more decades of experience of other craft from Windsurfers to Round The World Racing Yachts on inland waters and offshore - see my "Boating Background" for more details.

I will try to be as fair and unbiased as I can.  I don't claim to be the world's greatest paddling expert and no doubt many experts will have opinions that disagree with mine.  Nevertheless I must have learnt something over the last few decades so I hope that this information below may be of use to many new entrants to the wonderful world of paddling!  I will only cover kayaks and canoes here and will not cover the growing craze for Paddleboards as I have little experience with these.  In general though a Paddleboard can just be regarded as a particular form of Canoe so some of the general statements will apply.

Beware of on-line media, the internet and the likes of Facebook and Twitter which can be can be great sources of information but it is wise to take opinions and recommendations with a pinch of salt. I see many forum discussions where misleading or incorrect information is given then repeated by others as fact.  There also seems to be a tendency for people to immediately advise you to join a club or buy a Sit Inside Kayak rather than the Sit On Top kayak or inflatable that you had asked about buying.  That might be good advice in some circumstances but sometimes that would not be the best solution to fulfil your unique requirements.  I often find this particularly with clubs and club members who are primarily white water kayakers and who often steer people in that direction rather than towards the easy entry laid back Sit On Top Kayak cruising that the person enquiring really wants to do.  I love paddling my composite sea kayaks but for some uses a Sit-On-Top kayak is a much better craft for the job so I would have no qualms about using one, and often do, if it is a better suited to the type of paddling I am doing.  One type is not inherently "better" than the other as such, they are just different and fulfil different roles and only you can determine the best boat for you and your particular circumstances.  In a perfect world it would be best to try out as many different boats as you can as it is not until you have paddled each one for a while that you can understand it's particular character and capabilities.  Also be a little wary, on forums you often see beginners proclaiming that their latest "bargain price" boat is the bees knees, and for them it may well be and be all they ever need, but it is not until you actually try higher quality, better perfoming craft, that you realise just how good they can actually be and what a pleasure it is to paddle them.  You also don't see how badly deformed, soft, deteriorated or scrapped a low quality plastic boat can be 5 or 10 years hence when the originally more expensive boat is still going strong and now looking like more of a bargain and still has retained a re-sale value.

Some general information-  Certain craft are more suited to certain tasks than others and in general this is determined by the physical characteristics.  Most craft are a compromise and are good at one thing and not so good at another.  You can't get a single craft that is the best in it's class at everything (or if you can patent the idea now and make a fortune!).  The key is getting a craft that best suits your particular needs and compromises more on things that are not so important to you.  Try to make a realistic list of the things that are important to you, the style of paddling and types of water you want to paddle and the the things you might want to carry with you and then match a boat to those requirements.  If your requirements are too wide ranging it may  be that you actually need more than one boat (Probably why I currently have 7 !) so prioritise what you would like to do first.  I'll try to describe some physical attributes that govern certain general characteristics so you will have an idea of what features to look for.  I have seen some people who want to go cruising on flat water come in to buy a small white water kayak just because it is the right size to squeeze inside their car.  While you can use a short white water kayak for cruising (and indeed I did on  a recent yacht trip in Scotland purely because it was the only boat that would fit on the back of the yacht) it is not ideal and for most beginners this would just be a lesson in frustration as short white water kayaks are designed to go down flowing rivers and turn very fast to negotiate rocks etc.  What they are not designed to do is paddle in a straight line on still/slow moving water where they will have a low top speed and may be extremely difficult to make go in a straight line so making them quite hard work and even put beginners off kayaking.  If however you want to go down white water rapids etc then a shorter white water boat would be ideal.

Boat Speed - The maximum speed of any Kayak or Canoe, or any other type of mono-hulled displacement craft, is governed by the overall waterline length, that is the length of the hull that is floating in the water at the waterline.  This is not the same as the overall length of the vessel as most craft will have overhangs at the front (bow) and rear (stern) so the waterline length will always be shorter than the overall  length. In general, all things being equal, a longer hull/waterline length will be easier to drive and have a faster top speed and cruising speed than a shorter hull.  That is why most sea kayaks designed to cover longer distances, or combat fast tidal currents, will be 16-18 feet long or even longer.  As long as the vessel is in displacement mode, ie travelling along normally not  surfing on top of the water, then the top speed it can travel at is governed by the laws of physics and it doesn't matter if you are a leisure paddler or an olympic champion the boat is not going to go any faster than what is know as the "Maximum hull speed" . You may be able to get it to surf (or "Plane") without a wave for a short time by putting in a great deal of energy and effort but most people cannot keep up that pace for more than a few seconds. Basically when you get to "Hull Speed" you just start putting a lot of energy into creating your own bow wave and then trying to climb to the top of it so you are effectively paddling up hill.

Maximum hull speeed can be calculated and the maximum hull speed in Knots (1 Knot = 1 nautical mile per hour = 1.15 statute miles per hour) is approximately equal to 1.34 times the square root of the waterline length (measured in feet).  As an example a sea kayak with a waterline length of 15ft may have a top speed of 6mph while a short white water boat with a waterline length of 7ft may have a top speed of 4mph (and be much harder to keep in a straight line at that speed).  This may not sound like much but on a 5 hour paddle the sea kayak could have covered 30 miles while the white water boat has only covered 20 miles and still has 2.5 hours to go to reach the same pub!  In reality most people are unlikely to maintain a cruising speed of much more than 2/3rds the maximum hull speed but the relative difference will still be similar.  More importantly if you get caught in a 5mph current or rip tide the sea kayak could still make 1mph against it but the white water kayak would be paddling flat out and still going backwards by 1mph (possibly towards Holland!).  Other factors like hull shape and drag caused by e.g. scupper holes in sit on tops means you might have to put more or less effort into actually reaching the maximum hull speed or maintaining cruising speed.  Put simply a longer low drag boat will get you where you are going more quickly and with less effort, or let you go further in the available time, than a shorter craft and has that little extra in reserve if you have to battle an adverse tide or current.

The table below gives just an approximate rough guide to likely speeds for different waterline lengths although paddling expertise, fitness and the design of individual craft will affect the actual speeds attained.and those maintained over an extended time/distance (So don't write to me complaining your kayak/canoe is much faster/slower  than this!).

Manoeuvrability and straight line tracking -  In general a short kayak will be more manoeuvrable and turn faster than a long kayak but harder to paddle in a straight line (often called tracking) without wandering from side to side and be slower.  A hull with more rocker (More of a banana shape with upturned ends when looked at from the side) will be more manoeuvrable than a boat of the same size with a flat hull profile but probably slightly slower. Some boats have a drop down fin called a skeg which helps to keep them in a staight line when you need to but can be lifted to allow you to turn faster in other situations giving you more flexibilty -This is particularly true of so called "Cross Over" boats (e.g. the Dagger Katana, Wave Sport Ethos or Pyranha Fusion) which are billed as multi purpose boats able to cruise in a straight line on flat water or the sea as well as tackle "white water" and rapids where the ability to turn quickly to slalom around rocks is desirable. Some boats have more of skeg/keel shape built into the design of the boat to aid straight line. In general you can get a good idea of a boats characteristics and how it is likely to handle just by looking at the hull shape.  As you get more expert at paddling you will learn "edging" techniques whereby you can heel/lean a boat over as you turn which has the effect of lifting the bow and stern out of the water slightly allowing the boat to turn more quickly (as though it were a shorter boat) than it would otherwise do while retaining the overall length for straight line speed/efficiency.

See this example video from "Online Sea Kayaking" (They have some excellent tutorial courses) for an overview of "Edging" - It doesn't have to be a sea kayak, the principle applies to all kayaks/canoes.

Type of Paddle Craft

Kayak

A Sit Inside kayak is a craft paddled with a double ended paddle normally with the paddler seated with their legs out in front of them.  Most, but not all will have have a deck that prevents water getting into the hull and protects the occupant.  Often the paddler will wear a spraydeck or sprayskirt around their chest/waist that clips over the rim of the cockpit thereby sealing out water and preventing the kayak filling with water from spray, waves or from being capsized.   Paddlers will often learn to roll so that in the event of a capsize they can roll the kayak back upright although this is not obligatory and there are other methods of self rescue. Rolling however is a great skill to learn and great fun when you have mastered it. It also makes kayaking less stressful as once you have mastered the roll you never need to worry about capsizing.  If you can't roll do a roll but do wear a spraydeck make sure you know how to release it should you find yourself upside down in the water.  If you are not wearing a spraydeck and capsize then you will probably find you just fall out of the cockpit anyway as it is actually easier to get out of a kayak upside down than it is to get in it the right way up so there is generally no need to worry about getting "trapped" in the kayak - Trying to stay in it upside down would be the diffcult part!   With all kayaks you tend to get some dampness while paddling as it is difficult to completely prevent water running down the paddles and basically into your lap or spraydeck, and I have found that very few spraydecks are 100% watertight. Sit Inside kayaks fitted with knee or thigh braces which you use to apply pressure via your knees/thighs to allow you to "edge" your kayak (tilt/heel your kayak over on it's side in a controlled manner) to aid turning or rolling give you more scope to develop advanced paddling techniques as you gain experience.

Sit-On-Top-Kayak

A "Sit-on-Top" kayak or SOT is basically the same as a kayak but with an open deck and a watertight hull with a double skin making it waterproof and effectively unsinkable.  They tend to be wider than "Sit In kayaks" for stability as the kayaker sits higher up due to the double hull.The kayaker sits on top of it with no deck or sprayskirt for protection.  The fact that it has no deck also means no protection from the elements or from the unavoidable drips off the paddle so unless it is scorching weather it is best to wear some form of waterproof leggings to stop getting a wet lap or legs!  In the event of a wave or a capsize the kayak is self  draining and any water on the deck or seating compartment  will drain away through "scupper holes" in the hull (drain holes).  Kayakers will generally not roll a sit on top back up (although some people can do it when the kayak is equipped with thigh straps) but will flip it back upright in the water while swimming then scramble back on board, however inelegantly.  This ability to easier self rescue without the need to learn to roll or bail the water out of the boat after recovery makes the Sit On Top kayak a particularly good choice for beginners and is also favoured by kayak anglers.  Sit On Top kayaks are also easier to get in and out of.  Due to the fact that they are wider than a normal kayak, and the scupper drain holes create some drag, they tend to be slightly slower than sit inside kayaks of the same length or require a little more effort to maintain the same speed.  Like sit inside kayaks they come in different sizes and styles from short manoeuvrable kayaks to long sleek faster tourers to wider fishing platforms to tandem or 3 person family boats so again list your priorities and intended use and pick an appropriate boat to suit your particular needs.  Some people fit plugs into the scupper/drain holes to prevent water splashing in through them.  Remember if you do this then you will lose the self draining capabilities of the kayak so best never to do this on the sea or in rough water.  I like to fit thigh straps when I paddle Sit-On-Top kayaks as this give me some purchase on the boat (or connection) akin to the "thigh Braces" fitted to many Sit Inside Kayaks and are especially useful when paddling on waves/surf when you don't want to get flicked out of the boat or if want to try "Edging" techniques for turning etc.  However, in general most Sit-On-Top kayaks are NOT the best platform to allow you to develop some of the more advanced kayaking techniques (or at least they are less responsive so make it more difficult) so if you think you want to go on to be a demon "Edger" or want to learn to roll then you may find a good Sit Inside Kayak to be more appropriate for you.  For many people who just want an easy to paddle relatively safe, stress free and stable platform for gentle leisure paddling then a Sit-On-Top may be the ideal solution and they may never feel the need to paddle anything else.

Canoe

Often know as an "Open Canoe" or a "Canadian Canoe".  Canoes are paddled with a single bladed paddle and do not usually have a deck (some may have spray covers for negotiating particularly rough water).  They are normally paddled from a higher bench type seat or from a kneeling position (Particularly in rough water).  In general canoes have a much higher load carrying capacity than kayaks so are great craft for camping expeditions with lots of gear or for carrying a family.  When paddled solo they are generally not as fast as a solo touring kayak but when paddled tandem (or more) they can get a pretty fast scoot on and give a kayak of equal length a good run for it's money. 

Canoes can be slightly more "civilized" to paddle than kayaks as they tend to be easier to get in to and out of and you are less likely to get wet/damp from paddle drips when using a single bladed paddle especially if you have mastered the J-Stroke minimising the need to swap the paddle from side to side as in the so called "sit and switch" method.  You also sit up higher and have more room to move and stretch your legs which some people find more comfortable.  We have even been known to use our canoe as transport from home to our local restaurant for a summer evening out dressed in our finery, something we are very unlikely to do in kayaks! 

Canoes though can be more difficult to self rescue in the event of a capsize, especially if you are solo, as in general they are heavier, bulkier, and will have more water in them when capsized and when emptied are higher out of the water so harder to get back aboard.  Fitting buoyancy bags, barrels etc in the boat to reduce the amount of water in them should you capsize may be of help especially if you are paddling in more remote or exposed areas with rougher water.  Having said that, in over 20 years of paddling open canoes including carrying passengers of various levels of ability and sense of balance, admittedly on primarily flat still water (although I have been down the Symonds Yat rapids), I have not yet managed to capsize my open canoe.

Solo canoes tend to be in the 12-16 feet long range although I regularly paddle my 17 foot long Old Town Penobscot 17 RX solo but it can be a handful when it is windy.  Tandem canoes are generally 15-17 feet long and those suitable for carrying a family 16-18 feet long.  In general the longer the canoe the higher the carrying capacity and the higher potential top speed.

In the same way as with kayaks, canoes with more "rocker" (the banana shape when viewed from the sides with upturned ends) will tend to be more manoeuvrable, and climb waves slightly better, than an equivalent canoe with a flatter profile but will be slightly less easy to keep in a straight line (especially when solo) and slightly slower than a straighter profile hull.  Those with higher sides will keep water out better in rough water but will catch the wind more on a windy day making them more difficult to handle especially when solo.  The Traditional, more rockered, "Prospector" canoe design is considered pretty much the do anything, go anywhere SUV/4x4 of canoes being capable of handling most conditions but a lower profile hull design (e.g. The Nova Craft Pal) will be more efficient if you paddle exclusively in flat water type conditions e.g. most of the Norfolk Broads.   Most manufacturers produce a hull along the lines of the traditional "Propector" type hull design within their range.

Construction

Kayaks and canoes can be made of a variety of material, some great, some not so great, some best avoided. 

Wood - is actually a superb boat building material especially when combined with modern expoxy and fibreglass material having a great strength to weight ratio.  New professionally built wooden craft are usually (very) expensive though as they are very labour intensive to build.  Buying a secondhand home built wooden craft can be very much a lottery as you cannot be sure of the skill of the original builder or quality of materials used (or amount of rot in the hull).  Generally wood also requires more looking after and maintenance and any damage to a wood epoxy hull needs immediate attention to prevent water seeping into the wood beneath the epoxy skin.  A well built wooden craft though can be a thing of real beauty and can often be lighter than the plastic equivalent while also being stiffer.  If you have the skills to build one yourself (and modern stitch and glue techniques using plywood, epoxy glue and fibreglass tape/cloth can make it relatively quick and easy) then it can be a cost effective way to get a new boat but be aware selling at a later date may be difficult.

Composite materials - Fibreglass, Carbon Fibre, Kevlar, Diolen,bonded with epoxy, vvinylester or polyester resins. etc. Most of the best sea kayaks are made of composite materials as it is far easier to get a a long stiff hull without making it excessively heavy.  The smooth surface also tends to create less friction giving better glide and faster boats.  Composite boats tend to be more expensive than plastic boats as they are much more labour intensive to make and the raw materials more expensive than making boats from melted plastic in a mould.  Composite boats can damaged and chipped more easily in rocky surroundings but generally it is quite easy to repair (easier than plastic and repairs can be more solid), almost ad infinitum, with woven glass fibre cloth (NOT chopped strand fibreglass mat which has little inherent strength) the correct resin and a gelcoat filler.  Composite boats have the potential to last longer than plastic boats.  My 25 year old much repaired NDK Romany is testament to that and I don't see why it shouldn't last another 25 years.  I have carried out long, hard, voyages in yachts made of fibreglass over 40 years old so the material is well proven.  Many older river kayaks were made out fibreglass but have fallen out of fashion in favour of newer plastic designs.  However, don't discount the old fibreglass river kayaks which can usually be bought for a song or are sometimes given away.  Just for gentle flat water cruising they can be a very cheap way of getting on the water and are often faster than plastic designs.  Be aware though that fibreglass has no inherent internal buoyancy so a flooded fibreglass kayak may sink.  Modern fibreglass kayaks usually have bulkheads and waterproof compartments for bouyancy.  Many of the old boats do not have compartments built in so either fit waterproof bulkheads or ensure that the hull is fitted with well secured inflatable bouyancy bags (or polystyrene foam blocks) to give bouyancy and reduce the amount of water taken on board in case of a capsize.  A couple of years ago I had to rescue a chap on his maiden voyage in an "ebay special" ancient fibreglass canoe who I came across in the water the middle of the river in the path of motor cruisers.  The kayak was a narrow and tippy design totally unsuitable for a beginner and had no bouyancy in it so was only barely floating because an air bubble was trapped in the nose.  It weighed a ton filled with the water and took a considerable effort to empty and get him back aboard and then advise him to slowly and carefully paddle back the 500 yards he had managed to paddle from his launching spot before capsizing and take the boat home. So choose carefully!  Conversely both of my sons started kayaking in cheap fibreglass canoes but these had front and rear watertight bulkheads and a very stable design providing sterling service for several years for very little money and performed as well as any equivalent plastic design.

Plastic - The majority of mass produced modern kayaks and canoes are made of plastics and usually rotomoulded, i.e. plastic granules are poured into a mould, melted and then the mould is rotated to coat the inside of the mould evenly with hot plastic to form  the hull shape.  Once the plastic has cooled the mould is opened up and the kayak popped out.  It is a quick way of mass producing a kayak.  All plastics are not equal though and some are best avoided.  Plastic is not as stiff a material as fibreglass composite so it is not easy to make longer boats stiff enough without adding excessive plastic and thus weight which is one the reasons many sea kayaks are composite not plastic. The plastic can also sag or "oil can" in long flat areas and if left out in the hot summer sun, especially on roof racks, can sometimes deform (Bend). 

Some longer premium, primarily sea, kayaks and many canoes are made of "triple layer" materials with various trade names like Corelight or Royalex,  to enable them to be stiff without adding excessive weight.  To do this they typically have a layer of plastic then a layer of foam then another layer of plastic producing a foam sandwich construction which is much stiffer than just a single layer of plastic (even thick plastic).  This premium construction also comes at a more premium price. White water boats designed to bounce off rocks frequently just tend to use rugged single layer plastic as this more flexible plastic can absorb impacts better and the shorter kayaks do not tend to suffer from flex and deformation as much as longer kayaks and canoes.  Be aware that there are also heavier triple layer materials used, primarily  for lower priced open canoes e.g. SP3 use by Novacraft in some of it's range, which are heavier and not quite as stiff as the unfortunately no longer available "Royalex" material boats although the SP3 type material tends to be very robust and is certainly superior to a single layer plastic hull.  Lastly at the budget end of the market you see Open Canoes made of single or two layer plastic, often with a metal bar running down the centre of the canoe to help stiffen the bottom (and often with plastic seats with drinks holders or cool boxes built into them to help brace the metal bar!).  While offering sterling service and a large carrying capacity to families on a budget these boats tend to end up with ripples in the bottom as they age.  They also typically tend to be very flat bottomed with little to no rocker so don't handle as nicely as some of the more sophisticated designs, something to be aware of if you aspire to becoming a paddling maestro or want to indulge in some "canoe ballet"!

The type of plastic used is very important.  Cheaper bargain basement kayaks often use Low density polyethylene (LDPE or LLDPE) which is cheaper to buy and easier to mould but is more suited to making washing up bowls than kayaks and these may not be quite the bargains they first appear and can well end up in disappointment or put you off the sport for ever.  There is a reason why they are cheap despite some sellers even claiming this is the best plastic for kayaks.  Better quality, longer lasting, more abrasive resistant, stiffer and therefore better performing, kayaks are generally made out of Medium or High Density Polyethylene (MDPE and HDPE) and though usually more expensive will probably prove to be a better buy in the long run and have better re-sale value should you want to trade up (or give up) later.  Remember the old adage, buy cheap, buy twice!  -Click on this link for an explanation of which plastics to watch out for in kayak construction and a vivid video which clearly illustrates the difference  -  Explanation and Video - The difference between poor quality Low Density Polyethylene and good quality Medium or High Density Polyethylene in kayak construction .

 Inflatables - Inflatable kayaks and canoes can be a boon for those who don't have storage space or the ability to transport a "hard shell" boat.  As with plastic boats they come in various qualities and prices and again some of the cheaper boats made out of thin materials are best avoided as false economies and should be regarded more as cheap toys with a limited life span.   Most inflatables will have a proper, normally "Boston Type", air valve to inflate the main bladders through.  Anything that has a simple stopper type valve like a beachball is probably in the toy category except if just used for inflating the separate seats. Good quality inflatable kayaks/canoes are not cheap and will cost as much as many "Hard Shell" boats.  As with all plastic/rubber type materials, sunlight is one of the biggests dangers to the materials causing them to age, stiffen and crack as well as lose colour so always try to store your boat out of sunlight and preferably also give the material a wipe over with "303 Aerospace Protectant" (Basically suntan lotion/conditioner for plastic and rubber) from time to time.

Inflatable boats don't tend to perform as well as hard shell boats as they are primarily a bubble of air sitting on top of the water rather than in it so are very susceptible to being blown about in the wind and the draggy hull shapes are not as efficient to paddle and have very little "glide" when you pause paddling.  They do though tend to be fairly capacious and very stable.  Many will have a small fin you can attach to the bottom to aid combating wind drift and to help keep you going in a straight line.

If you don't have a restriction that prevents you getting a hard shell boat (i.e. one made made of good quality solid plastic or fibreglass) instead of an inflatable then I would always steer you towards a hard shell boat of what ever kind suits you.  In general hard shell boats will be easier and more efficient to paddle (and get you home if conditions turn nasty, like a very strong wind picks up where you may find it impossible to paddle the inflatable against the wind), be sturdier and less prone to puncture (if picking blackberries along the river bank for instance or pushing through overgrown waterways or unseen underwater obstructions) and have a much longer life span.   Inflatable boats will also tend to have a lower re-sale value/retain less of their original value than a hard shell boat should you wish to trade up later.

Inflatable boats made of a rubber based laminated material such as Hypalon or Gumotex's Nitrilon tend to be longer lasting than those made of a PVC based material although there are inflatables made of a heavier weight PVC material similar to that used in motor RIBs that is longer lasting than standard PVC but still on the whole probably not as long lasting as the rubber based varieties.   I have had Hypalon yacht tenders (inflatable dinghies) still going strong at over 20 years of age. These boats also tend to have slightly higher inflation pressures which makes them stiffer and hold their shape better increasing paddling efficiency.  Patching Hypalon/Nitrilon boats is also easy and effective and is easier than mending a bicycle tyre as long as you use the correct materials.  The glues, made specifically for mending rubber based boats which come with a small bottle of hardener that you add to the rubber adhesive, provide the best and most permanent patches.  You can also get this "two pack" type of glue for PVC boats (make sure to get the PVC variant rather than the Rubber variant) which performs better than most simple single tube glues and is similar to the glue used to originally make the boats if they have proper overlapped seams rather than simple welded edges.

Some inflatable boats have a nylon/Cordura type protective outer covering with thin PVC air bladders inside. In these types there are usually three separate air bladders, one for each side and one for the bottom. The bladders themselves tend to be a very thin PVC material with simple welded seams.  It is essential with these NOT to over inflate them as it is not unknown for the bladders split at these seams.  The air bladders themselves can usually be replaced for somewhere between £30 and £80 EACH. The outside covering gives the bladders some protection from puntures but the disadvantages are 1.  The nylon covering tends to absorb water and become wet so you have to dry them thoroughly before stowing away (or carrying them in the car if not in a waterproof bag to prevent getting the car interior wet) or next time you come to use the boat you are likely to find a smelly, mildewy mess.  The wet boat can also weigh more than it did when you carried it down to the water!  2.  Sand and salt water can penetrate between the outer nylon/Cordura skin and the bladders leaving sand and salt crystals to cause wear and abrasion to the bladders and the outer covering.  Salt is also hydroscopic, absorbing water from the air, so causing dampness in materials even if they have previously dried out.  The Hypalon/Nitrilon rubber materials don't absorb water so once wiped or left to dry in the air kayaks made of this material can be stowed straight away.

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