Inflatable Boats

Most trips into the remote regions of Alaska involve stuffing your gear and your person into a small, single-engine aircraft and flying off into some isolated landing spot close to a river or a lake. But if you want to get onto the water, strapping an aluminum canoe to the side of the aircraft is no longer the option it once was. You need an inflatable boat.

Inflatable rafts on the river, Alaska

Introduction

Inflatables come in a bewildering array of shapes, sizes, colors and price ranges. How do you decide which one is right for you? The short story is to let the river choose the boat. What does that mean, you ask? In a nutshell it means that your choice is influenced by the character of the river more than any other single factor. Fast and narrow rivers that wind through timbered country require a small to medium-sized round boat. Big, broad water allows you to use large catarafts with outboards. Smaller streams with slow water allow the use of inflatable canoes or kayaks. So before you can make your choice, you need to know what kinds of rivers you will float.

Next, you need to know the kinds of loads you are likely to carry. A day-trip on the upper Kenai with a light load gives you lots of options. But a multi-day fishing expedition on the Goodnews River limits your options somewhat. Finally, a float hunting trip with a friend may require a big boat with lots of lift. Know your loads in advance and select your boat accordingly.

Let's look at the different styles of inflatable boats. In outlining them you will have much of the information you need in order to make a good selection.

Materials

Most raft fabrics start their lives in large factories that produce materials used for other purposes, such as pit liners to contain liquid waste, temporary inflatable buildings used by the military or by industry, and so on. Raft manufacturers routinely survey available materials to identify those most suitable for the manufacture of inflatable boats. These materials generally fall into one of two categories; rubber or plastic.

Rubber Fabrics

Rubber is much more flexible than plastic; it stretches more, it bounces, and it is much more flexible. It is also very abrasion-resistant, an excellent quality when you are considering floating shallow rivers where you may have to drag your boat. Rubber is found in one of two forms: CSM (synthetic rubber) or neoprene. By the way, CSM was originally marketed under DuPont's trade name "Hypalon". DuPont discontinued manufacturing it in 2009 and most boat builders have moved on to other manufacturers of CSM.

Inflatable boats are not made with pure CSM; the industry standard mix is 80% CSM and 20% filler materials. Cheaper imported boats may use a 50% CSM mix, but these coatings will prematurely oxidize and weather check. Rub your fingers across the material and if you see a chalky film on them, the compound is probably oxidizing. Keep shopping.

Neoprene is extremely abrasion-resistant, and is often used for chafer strips atop the tubes (to prevent tube wear-through from frame rubs) or on the bottom of the boat, to protect it from abrasion against the riverbed. Unfortunately, neoprene also grips when wet. This is why car tires are made with neoprene; it keeps them from sliding off the wet pavement when it rains. This tendency is a disadvantage if you have to pull your boat through shallow areas, a common occurance on many of Alaska's rivers.

Because rubber flexes and stretches, it may not be the best choice for narrow boats, which could fold in the middle ("taco") at the bottom of steep drops.

Plastic Fabrics

Plastic also comes in two types; Poly Vinyl Chloride (PVC) or urethane. PVC is a softer material that tends to scratch or gouge in abrasion situations. Urethane is the most abrasion-resistant material used for inflatable boats, but it is also the most expensive. It is applied during the manufacturing process in one of three ways:

  1. Calendaring. A urethane or PVC sheet is laminated on calendaring processboth sides of a polyester or nylon base cloth. AIRE and SOTAR produce boats utilizing this method.
  2. Spray coating. Liquid urethane is spray-coated over the surface of a rubber or PVC boat. Maravia has manufactured many boats using this technology. Some raft shops are equipped to spray urethane coating on the bottom of a boat, or to apply it as a chafer atop the tubes, to reduce frame abrasion.
  3. Bladder system. A pure urethane scrim is welded to form an airtight bladder, which is placed inside a PVC shell. AIRE invented this technology and manufactures nearly all their boats using this method.

Another factor to consider in inflatable boat construction involves the base cloth. The base cloth is a woven fabric scrim made from either nylon or polyester. A nylon scrim is stretchy and compliments the stretchy characteristics of rubber, and it is often used with those coatings. Poly is usually used with PVC or urethane, because it does not stretch, but provides excellent structural support. Most consumers need not be concerned with details such as the method of weave used in base cloths, however one concern can be the denier of the fibers themselves. The term "denier" is a French word indicating the weight, in grams, of 9,000 meters of thread. Thus, a denier of 1200 is thinner than a denier of 3600. But thicker thread, though stronger, is not always better.

Fabric Problems

Older raft manufacturers such as Achilles, Avon, Hyside, Northwest River Supplies and so on have experimented for many years with different fabric types, and have worked out most of the bugs that plagued the industry years ago. Some fabrics simply do not make for good boats. While most of the industry seems to have worked a lot of this out by following the industry leaders, smaller companies may still fall into the trap of using cheaper, inferior fabrics. It is therefore in the best interest of the consumer to educate yourself on what to look for in a poorly-made boat, and especially in inferior materials. Here are a few examples of poor materials or inferior workmanship.

Wicking

Sometimes the top and bottom coatings of the fabric don't adhere to each other very well through the base cloth, and bubbles can form as the material delaminates. Or air can travel through the exposed edge of the fabric, migrate all the way around the tube, and exit the boat along the exposed seam on the exterior. This is known as wicking, and the common remedy used to prevent it is to install seam tape along the exposed seams of the boat. Check for wicking by spraying exposed fabric edges with soapy water. If tiny bubbles form along the exposed edge, the material is wicking. 

Poor Fabric Adhesion

Another symptom of poor adhesion between the top and bottom coatings is the appearance of tiny bubbles in the surface of the material. Run your hand over it; the material should feel smooth, or you should be able to faintly see the weave of the base cloth. But there should be no bubbles in the fabric itself.

Oxidization

Rubber boats using a weak mix of CSM (Hypalon®) often show a white, chalky film on the surface, as the material oxidizes over time. This material will eventually break down, checking and cracking, until it will no longer hold air.

Poor Workmanship

It's easy to spot a poorly-built boat. Look for glue smears near the seams, improperly matching seams or voids, or slow leaks. If at all possible, fully inflate the boat and let it sit for a few days before purchasing it, or get the seller to agree to a return policy. Some leaks will not be apparent for a few days. Keep in mind that most leaks are a result of valve issues, and are easily fixed. But in some cases, the boat itself is a leaker and should be returned, if it's brand-new.

Boat Configurations

Many types of inflatable boats are available, but not all are appropriate for all situations in Alaska. Let's look at the various styles and the pros and cons of each, but before we do, let's define a couple of terms.

Round Boats 

When most people talk about a "raft", they are thinking of a round boat. It gets its name because of the oval or round bow and stern sections, which are joined together by straight side tubes of the same diameter. Several variations of the round boat include boats with bullet-shaped bows, flat sterns, enlarged or diminished-diameter tubes in the bow or stern or other variations designed to improve performance in certain conditions.

Self-Bailers

This term refers to a round boat with an inflatable floor and holes around the perimeter that are present to allow water to flow out of the boat. Water can enter a round boat through splashing, multiple entry-exit cycles of passengers, and rainfall. However it gets there, it amounts to a lot of extra weight and having it drain out on its own is a huge benefit.

Check out our Round Boats page for a detailed discussion of the various types, features, and preferences for float hunting or other expedition trips.

Catarafts

A cataraft, or "cat boat" is essentially twin tubes connected by a frame of some sort. Some cats are made with twin tubes on each side, for greater lift, and, just as is the case with round boats, cats come in many sizes and tube diameters. Check out our Cataraft page for more details.

Pack Rafts

A pack raft is a tiny round boat designed for one person and, with some models, a very light gear load. Pack rafts may weigh as little as 4 pounds and pack into a space about the size of a Thermos bottle. They are ideal for situations where rivers must be crossed that are too deep to wade, or for hike-in situations. There is a growing trend among the float hunting community to use pack rafts as primary floatation on extended hunting trips. There are numerous risks with this, such as the fact that game meat will get wet in a pack raft, adding to field care difficulties. A second and major point involves the thinness of the material and the risk of a catastrophic tube failure when floating heavy loads over rocks.

Inflatable Canoes

Inflatable canoes are popular on smaller streams that don't accommodate other boats. They're great for flyout trips as a primary conveyance or simply for a way to access smaller streams, sloughs, oxbow ponds and lakes off of the main waterways. Choose a canoe that fits your situation. On rivers where portaging is likely, it might be best to select a lighter-weight boat such as the AIRE Traveler or the Incept C42T, but for expedition trips where big loads are encountered, a larger, heavier boat such as the SOAR Pro Pioneer or the SOAR Magnum might be in order. Check out our Inflatable Canoes page for more details on these and other inflatable canoes.

A Word on Boat Capacities

There are no objective industry standards for calculating the capacity of an inflatable boat. In fact, most reputable manufacturers no longer post capacity statistics. There are too many variables to make such numbers reliable; a whitewater paddle boat should ride high and be easily maneuverable, but put a frame on the same rig and put it on slow Class I-II water on an extended expedition float and you can afford more weight aboard. The best standard is to "let the river choose the boat". That is to say, look at the river conditions, combined with the loads you intend to carry, before choosing a rig. There are no "one size fits all" solutions when it comes to inflatable boats. If you are in the market to purchase or rent a boat for an extended Alaska expedition, it's in your best interest to rent before you buy. Take a couple of shake-down cruises with a load similar to what you plan to carry on your trip; that, more than anything, will tell you what to expect, and which boat to choose.


Need More Info?

Check out our Float Hunting pages, which contain a page on Inflatable Boats for Float Hunting. If you would like to interact with other Alaska river floaters, check out our Alaska Boating Forums or our Float Hunting Forum. Are you looking for a reputable inflatable boat dealer or rental outfit in Alaska? Check out our Inflatable Boats listings in our Directory. For reviews on particular brands of inflatable boats, have a look at our Inflatable Boats Product Review section, where you will find reviews on popular brands.

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