Grabner Discovery 2 inflatable kayak review and comparison with Incept Tasman and Feathercraft Heron
The Grabner Discovery line consists of 2 boats that are a hybrid between an inflatable and folding aluminum frame kayak. It seems that Grabner has a lot of experience with inflatable boats and that part of this kayak is well designed and made with very durable high quality material. Unlike most inflatables that have 3 air chambers these ones only have 2, one on each side while the frame components eliminate the need for a bottom chamber to keep the hull rigid (more on that later)
In the spring of 2011 I purchased the larger of the 2 Discoverys, the Discovery 2, for better cargo volume and weight capactiy. Before purchasing this boat my only kayaking experience had been touring with an Incept Tasman 1 person inflatable so it’s inevitable that I should compare the two. A major difference is that the Discovery 2 is an over 18 foot long tandem model that can easily be adapted to solo use whereas the Tasman is Incept’s solo kayak model at only a little over 14 feet long. I found that the Grabner would glide through choppy water much more easily than the Tasman which would only glide easily on very calm water. Whenever conditions got a little choppy it felt like the Tasman bow was getting bounced around a lot and thereby detracting from forward momentum. I think though that the Tasman surfed in following seas a bit better than the Discovery since the longer boat is also more flexible (again, more on that later)
I liked how the Tasman has built in pressure relief valves and the input valves are accessible from inside the cockpit with a hand held pump so you can easily top off the air while on the water in order to maximize hull rigidity as much as possible. With the Discovery there are optional inline pressure relief valves that I found very useful while pumping up the chambers without a pressure gauge. The 2 valves are not accessible from the cockpit, though maybe they would be in tandem mode but then maintaining maximum pressure shouldn’t be as important in this boat that has a frame to help maintain hull rigidity. I still think it would be nice though to have built in valves just to eliminate the possibility of damaging the air chambers when the boat is on a beach under the sun when you’ve stopped for lunch. As it is you have to remember to manually let out some air in those conditions.
I like the spray deck for the Discovery which attaches to the hull with 2 velcro strips and a number of small metal hooks that fit in tiny holes in an extra layer of rubber on both sides of the boat or can be left off entirely for paddling on very flat water. Although these hooks are quite numerous once in place you only have to undo a few of them to access the generous cargo areas behind the seat and in front of the foot pedals. I was concerned that some waves might wash up under the deck and contribute significantly to bilge water but I found this was not the case at all and even though a little bit did leak in from time to time it was very minimal. In contrast the Tasman has a spray deck that is permanently attached on one side and with a zipper on the other side which is quite long and affords even better access to the cargo areas. I had quite a bit of trouble with water dripping off of my paddle onto the this zipper and into the boat pooling right in the seat so I often ended up sitting in a pool of water which wasn’t a pleasant experience. It seems that when Incept manufactures these boats they are supposed to punch 2 small holes in the section of rubber that connects the zipper to to the side air chamber BUT somehow they had neglected to do the boat that I ended up buying. Many months after the problem was identified they finally emailed me instructions on how to punch these holes myself but before I got around to actually doing it I had bought the Discovery and had mostly forgotten about the Tasman which I later sold on Craigslist.
When considering the Discovery’s aluminum frame it would seem that Grabner has much less experience in that area. I don’t think they designed this frame as well as they could have. Their implementation makes the boat rather fragile and a bit too flexible. You cannot pick it up by a gunwale, you need to use either a kayak cart or have two people carry it from either end or risk damage. I was also able to move it very short distances by “walking” it along the shore, lifting it alternately from each end, always fully unloaded of course.
The frame consists not only of aluminum tubes but also 3 large interlocking rigid plastic floor plates. They do a good job of keeping the hull rigid as long as they are pushed together very tightly which depends on the rigidity of the aluminum frame. I found the latter to be the biggest flaw in Grabner’s design. The aluminum tubes are connected with short plastic connectors that seem quite rigid but can get significantly bent out of shape especially in the 2 most critical joints along the hull in the bow and stern. I believe that handling the assembled boat out of the water on the cart and also trying to use the storage shelf provided to me by my kayak club caused both of these joints to bend to the point where the hull line was very noticeably not straight and insufficient pressure was put on the floor plates so that the boat felt weird in the water as the whole thing had become very flexible! I procured replacement plastic connectors from Grabner but they were soon bent out of shape also.
I was becoming somewhat disappointed with my purchase at that point and I decided that the only way to salvage my investment would be to replace the plastic connectors with a more suitable material, at least the ones in the 2 critical, high stress joints. I think that the connectors should have been made with aluminum though Grabner told me that when they were considering different materials they ruled out aluminum as they felt that could cause difficulties in separating the tubes. I had extreme difficulty separating these joints where the plastic pieces were very bent and deformed and ended up drilling one of them out! Feathercraft makes some of the best aluminum frame kayaks in the world and they don’t seem to have any problem using aluminum connectors to connect aluminum tubes, they just recommend to put some lubrication on them periodically which doesn’t seem like an unreasonable burden on the end user.
The outside diameter for these connectors is about 21mm or 13/16″ which is not a standard size for aluminum tubing or even wooden dowels. I ended up having dowels custom made from white oak by a local wood shop that was only willing to accept such a small job because business was slow at the time. (I hope they’re doing better now!) I replaced 4 of the plastic connectors with the dowels that I had coated with spray on polyurethane and found them to be much more durable holding up well over a 2 week expedition from Brooklyn to Montauk Long Island! The poly didn’t hold up so well on the 2 joints along the hull that were often exposed to bilge water but at least they didn’t get bent out of shape. I might try marine varnish instead of polyurethane if I ever feel like working on this frame again but I’ve since realized that seat posts for older bicycles are just about the perfect size at 13/16″ and as they are made out of stainless steel shouldn’t suffer from the salt water so much as long they are greased or lubricated.
Another issue with the Discovery is that the shock chords that keep the tube segments connected when disassembled became unhooked. This was not such a problem because I would have had to unhook them myself anyway to replace the 4 bent plastic connectors, bow and stern, along the hull and under the deck . There are only 4 other connectors in the whole frame, making 8 total, and those are 2 each in the gunwale tubes on each side of the boat. The chords on those are intact and the other ones are easy enough to place when you consider the layout of the other frame parts.
At the time I purchased the Grabner boat I was enticed by a very substantial discount they were offering on a 2nd quality boat with some purely cosmetic defects in the rubber. I have never noticed these defects myself. This unit was one of only a few number of remaining stock which is all gone now. I don’t know if Grabner plans to manufacture any more Discoverys ever, though if they do I hope they try to correct some of the issues with the first models.
Now if I had known at the time that Feathercraft had just come out with an all new model I might have passed on the Discovery but I didn’t find out about the Heron until a few months later. I was aware of their K1 model that was extremely suitable for my activites but more expensive and some reviewers mention it being a little slow. I knew of their Khatasalano model as well but that seems too sporty and unstable for me since my principal kayaking activity is expedition touring. I think I also used to favor inflatables because of their simple assembly but after all the hours I have spent messing around with the Grabner Discovery frame I now welcome the opportunity to work with a better frame designed and built by the experts in aluminum frame folding kayaks.
So then about a year after purchasing the Grabner, with my sights set on a summer spent paddling in Sardinia, I went ahead and ordered a Heron. I got it through Folding Kayak Adventures in Colorado instead of directly from Feathercraft in Vancouver in order to save on foreign transaction fees. Hopefully this is the last high end travel kayak I ever have to buy for myself.
Having already received the Heron and assembling it twice I’ll say I’m very impressed, especially when comparing it’s frame to the one in the Discovery! Yes there are many many more sections of aluminum tubing and more connectors, but most of them are shock corded together and the ones that aren’t are color coded in a way that eliminates any possibility of confusion during assembly. I am very impressed by one feature in particular where the whole frame length can be adjusted to 5 different possible settings in order to make it fit as tightly as possible into the skin and keep the boat rigid. I’m told that the skin can expand and contract depending on temperature and moisture and I’m assuming you may have to stretch it further after it has been well broken in, but we’ll see…
At this point I can’t compare how the Heron handles on the water because I am still just a warm weather kayaker and the water is pretty cold around Brooklyn this time of year. I do however like the bag and cart system I got for the Heron much better than what I got with the Discovery. The Discovery bag is very flexible with only flaps and straps with buckles to close it up but then it’s never really sealed because it has no zippers like the Feathercraft bag which while not as flexible is perfectly suited to the boat, with plenty of extra space for extras like a Northern Light aleut stuyle paddle, bilge pump and inflatable pfd. Removing the voluminous sea sock that Feathercraft provides I’m also able to fit in a Wheeleez mini kayak cart with it’s fat wheels deflated and shoved side by side down into the bottom of the bag.
For the Discovery I had purchased the optional Ekla convertible cart provided by Grabner that can be used as a luggage cart for the kayak bag or as a kayak cart for the assembled kayak. This is a great idea but in practice it ends up being a little too bulky and awkward for either application. As a luggage cart the wheels are too big and rub against the bag as they roll. It would be ok if they were positioned differently but that would require even more aluminum tubing and make the whole thing even more bulky than it already is. This thing is capable of other configurations besides these 2, presumably for other applications with other types of equipment though I have no idea what they might be.
For the Heron I purchased their optional pack cart that attaches to the outside of the kayak bag converting it into a wheeled piece of luggage. It is very light and simple and can be taken apart and stowed inside the bag itself when you get to the baggage counter 😉 I can’t really imagine checking in the full Discovery bag and cart. Feathercraft also offers a folding kayak cart but it’s not super light weight and the wheels don’t look suitable for many types of terrain so I instead opted for the Wheeleez mini which is supposed to be a bit lighter and should be able to roll over many more surfaces, including mud and sand.
It might seem that a comparison between a Grabner Discovery 2 and a Feathercraft Heron is somewhat unfair considering that the Heron costs more and they are actually 2 different types of boats. In reality though the Heron doesn’t cost that much more than what the brand new first quality Discovery 2s were going for with comparable accessories added on and although the Discovery is an inflatable and the Heron is not they both have aluminum frames, are about the same length, weight and capacity, pack to about the same size and are suitable for the same kinds of expedition touring adventures. I’ve learned quite a lot here and it seems to me that there is still room for innovation in the field of light weight, high performance, high capacity, collapsible expedition touring kayaks. Hopefully others can learn something from my experiences here also.