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 Post subject: New Russian Boat
PostPosted: Mon Jul 26, 2010 1:30 pm 
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http://www.aquagraphic.spb.ru:8080/index.jsp?V4.7.htm

Great boat!
The one that I got is a "Viking 4.7".

Basic construction is radically different from anything I've seen so far.
There are two 12'' high-pressure inflatable tubes running the length of the boat. They give the boat strength and rigidity. Each tube is split in two halves down the middle of the boat for fault tolerance. In addition, there is a single metal tube that acts like keelson. In reality, it does nothing exscept fixating the inflatable seats and provide directional stability. Then, there are inflatable seats that in addition to seating act like crossribs by spreading the long tubes and adding further rigidity to the boat.

As far as safety goes, the boat has 7 independent air chambers.

Mine was a custom order:
15ft by 36'', about 30lbs, takes 10-15 mins to put together.
3 seats, without the middle metal bracket.
Also, I ordered mine with only a partial deck. Kind of like the boat at the bottom of this page, only longer:
http://www.aquagraphic.spb.ru:8080/index.jsp?V3.8.htm

Also, my boat now has oar locks glued at middle. I find this option simply awesome!

So far, I used the boat on lakes and lazy rivers. Either with two adults (including me) or myself and two kids.

In short, I am very happy with it.


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 Post subject: Re: New Russian Boat
PostPosted: Mon Jul 26, 2010 1:48 pm 
knight of the folding kayak realm
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Location: Ireland
Thanks for this. Interesting looking boats, sort of a frame-inflatable hybrid like Tom Yost's Sonnet.

I'm not sure I like the look of the central joint though:
Image

Looks kinda fiddly, and I imagine the shearing force on that screw is potentially large. But I'm sure it works fine.

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2003 - Feathercraft Kahuna
2004 - Klepper Alu-lite (guest boat)
2005 - Feathercraft Khatsalano


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 Post subject: Re: New Russian Boat
PostPosted: Mon Jul 26, 2010 2:25 pm 
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Joined: Thu Apr 17, 2008 11:23 am
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It is quite different from Tom's boats.
Tom's boats use low-pressure tubes inside vinyl pockets that are in turn glued into boats' skins.
This boat, on the other hand, uses high-pressure tubes that are part of the skin itself.

My boat, apparently is of an older generation and its keel is joined differently, with a less technological method.

Essentially, there's a 1/4'' of a smaller diameter tube that sticks out of the stern part of the keel. The smaller diameter tube is riveted in place. As the boat is put together, the keel bow and stern parts are joined by that protruding smaller tube being slid into the bow part of the keel. Then, a larger diameter tube is slid over this joint and secured there with two hose clamps.

I know, that sounds complicated. However, in reality the whole process of joining, spreading and securing the keel takes less than a minute. With a new approach pictured on the site, it should take even less time.

As far as reliability of that connection goes, I would not be worried.
See, the boat can easily be used without the metal tube. That tube is not structural. Instead, much like Tom Yost's inflatables, the keel tube is used only to improve directional stability. Think of it as a nicer looking skeg of sorts.


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 Post subject: Re: New Russian Boat
PostPosted: Mon Jul 26, 2010 2:29 pm 
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I see, so really these are more like a kayak version of a RIB then?

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Nohoval

2003 - Feathercraft Kahuna
2004 - Klepper Alu-lite (guest boat)
2005 - Feathercraft Khatsalano


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 Post subject: Re: New Russian Boat
PostPosted: Mon Jul 26, 2010 3:20 pm 
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Location: Philadelphia
No, they are not.
In a RIB, there's a structural fiberglass bottom that has its floatation augmented by an inflatable ring along its top edge.

Here you have a rigid inflatable boat that has its directional stability aided by a tubular keel.

Think of it as a more rigid Tom Yost-type of boat with fewer metal parts.


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 Post subject: Re: New Russian Boat
PostPosted: Mon Jul 26, 2010 3:47 pm 
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Emmm...

Quote:
Here you have a rigid inflatable boat that has its directional stability aided by a tubular keel.


Right, so nothing like a RIB then. Got it. :?

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Nohoval

2003 - Feathercraft Kahuna
2004 - Klepper Alu-lite (guest boat)
2005 - Feathercraft Khatsalano


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 Post subject: Re: New Russian Boat
PostPosted: Mon Jul 26, 2010 7:09 pm 
nohoval_turrets wrote:
Thanks for this. Interesting looking boats, sort of a frame-inflatable hybrid like Tom Yost's Sonnet.

I'm not sure I like the look of the central joint though:

Looks kinda fiddly, and I imagine the shearing force on that screw is potentially large. But I'm sure it works fine.

It reminds me of usable (but not overly highly regarded even on unspoiled Russian markets) Russian inflatable Shuka, that one had no keel but did have lateral aluminum spreaders. This Viking looks more like a whitewater craft than Tom Yost's kayaks (bordering with rafts, if you consider 36" - 38" width at 15 ft length).

I can't be sure that this particular joint works fine, or that other joints work fine (there are some plastic hinges and clamps on the photos). The only way to make sure of this is to try it for a few weeks. Spreaders in Shuka worked, but missing backrest, footrest, poor design of torso skirt, poor tracking and inevitable windage (problem with many inflatables) made me sell it very soon. May be I just tried using it not what it was meant for - I'm not into white water paddling.


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 Post subject: Re: New Russian Boat
PostPosted: Tue Jul 27, 2010 10:33 am 
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This boat has as much in common with Shuka as a volleyball has with a beach ball.

1. Shuka's aluminum spreaders are part of the structure, while Viking's keel is not (remove the spreaders and the boat is not usable, while with no keel, Viking would just struggle to stay on course).
2. Shuka is constructed with an outer shell stuffed with low-pressure tubes. Viking, on the other hand is built with a single layer skin, simplifying storage and putting together the boat immensely. Also, Viking can be inflated to a very high pressure, making paddling more efficient.
3. Shuka is barely a boat. It has three rediculously low things going for it: price, weight and quality. Most of the people who buy it, get it for moderate white water with lots of portaging. In such conditions, low weight trumps on-water performance. Viking is 100% universal craft that can be used in just about any conditions. Sure, it's no Greenland kayak and more of a canoe - sort of like original Pouches, Kleppers, Folbots, Taimens, etc. However, it paddles great, stays on course and goes really well against the wind. I'd say on par with folding kayaks and way better than any inflatables I've tried, including a famous Grabner.

As far as the keel joint is concerned, I've had the boat since this winter and had no trouble with it.


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 Post subject: Re: New Russian Boat
PostPosted: Thu Jul 29, 2010 4:38 am 
Quote:
1. Shuka's aluminum spreaders are part of the structure, while Viking's keel is not

There are spreaders on the photos in those links above. I didn't mean the keel. Btw, keel is not a "skeg of sorts "- it has more to do with cross-section, i.e. primary stability and to a lesser degree - with windage, but has little to do with tracking.

Quote:
it's no Greenland kayak and more of a canoe

Its width and shape makes it different from many types of kayaks, not only from Greenland. Open deck design makes it somewhat similar to canoe, agreed. Back-less seats - too. (Or - similar to a raft). Another thing that makes it similar to open-deck vessel is that it has no usable sprayskirts - I mean that skirt won't hold well if you put it there, the rim is narrow, no "lip".

I wouldn't compare Viking to original Klepper or Folbot (not sure what "original" meant there, will assume it included those boats before Cooper, Kiawah and Alu-lite). There are no chines or gunwales in Viking. Could be the photos, but it looks that this boat practically rests on the sponsons like flat-bottom inflatable or raft.

Sponsons integrated into skin are not always a good idea. Difficult to repair and impossible to replace - though punctures are less likely since it's the same thick material on the cockpit side. Not a common solution on folders. The only time when I had to fix a "detached" sponson on Longhaul was not because of puncture on the cockpit side, but because the inflation hose developed a crack in the "elbow" where it joined the sponson. I did carry a spare sponson and in a pinch would have replaced it in a few minutes (thing not possible with integrated sponson), but decided to try and repair it first, since had already made it to the camp and wasn't in a hurry.
Which reminds me of another critical difference of Klepper/Folbot from Viking - the former type remains usable (some more, some less) with one sponson deflated. OTH, Viking has no frame and its sponsons become structural elements instead, which makes it an inflatable. With keel (non-structural, like optional backbone in Advanced Elements) and with spreader(s) - I think it has one spreader. That's why it reminded me Shuka - the only inflatable with added metal that I saw "in flesh", though Viking has more pronounced bow/stern ends.


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 Post subject: Re: New Russian Boat
PostPosted: Thu Jul 29, 2010 12:31 pm 
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I see your point with spreaders. However, I ordered my boat with 3 seats and no metal spreader in the middle.

You would be partially correct (in my opinion) in terms of the keel in traditional boats. However, in Viking and Tom Yost's designs, keels serve mostly as full-length skegs, helping out with tracking and windage.

If you look at pictures, standard design for Viking 4.7 is a closed, non-removable deck. Practically identical to Tom Yost's approach. Standard skirts have no trouble attaching to the aluminum coaming in that boat.

I happened to order my boat without a deck because I wanted flexibility with loading, centering and have the ability to row in addition to paddling. My configuration though is 100% custom.

I compared Viking to Kleppers and Folbots of old NOT in the sense of construction or shape. Instead, the comparison was in terms of their function. Back then, these were universal crafts that were equally handy at moderate white water and relaxed cruising. Mind you, neither them nor Viking were/are the best at any of those tasks, but they do represent a nice compromise.

Furtermore, much like Tom's designs, Viking does rest on its sponsoons, with the keel protruding into the water, defining the bottom of the boat.

Another thing, sponsons here are completely different from those in traditional folders. Instead of only smooting out the shape, these ARE the structure. They are no more likely to be damaged than hulls of inflatable catamarans, RIBS or virtually all high-end inflatables.

It is a common misconception that a single-ply boat is less durable that two-ply. Single-ply boats can be typically inflated to much higher pressure. Manufacturers like Incept, Grabner, Custom Inflatables, JPW, Innova and many others had seen the benefits of this approach. In the mean while, I am aware of only AIRE that had stuck with two-ply construction method and still produce reasonably rigid inflatables.

Another thing is difficulty in repairs. Repairing a PVC inflatable hull is no more time consuming or difficult than repairing a PVC skin of the folder. Just take your time degreasing the area and use the right cement and material for your patch. Typically, you're ready to paddle in under one hour. Compare that to spending the same time to fix the internal bladder, but needing to first take it out and then insert it back into its place.

As I had mentioned, Viking has FOUR independent chambers running length wise. If one gets punctured, the boat would still remain very usable, albeit very slowly.


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 Post subject: Re: New Russian Boat
PostPosted: Thu Jul 29, 2010 7:11 pm 
Cactus wrote:
...However, in Viking and Tom Yost's designs, keels serve mostly as full-length skegs, helping out with tracking and windage.

If you look at pictures, standard design for Viking 4.7 is a closed, non-removable deck. Practically identical to Tom Yost's approach. Standard skirts have no trouble attaching to the aluminum coaming in that boat.

Cactus, there is no such thing as a full length skeg. Skeg is a skeg and keel is a keel.

There is little in common between Viking and Tom's boats (even those his hybrids). All Tom's boats have structural keel and stringers and at least 1 rib or spreader; long sections of stringers take over the function of missing ribs in hybrids like Sonnet. Other Tom's boats have all the elements of a normal "framed" folder, including deckridge and several ribs. To me Viking looks much closer to inflatables like Advanced Elements with backbone than to hybrids like Sonnet.

Coaming: yes, there is no trouble attaching skirt to aluminum tube of the coaming, but it's too easy to take it off as well. Sonnet is Tom's only line of products with coaming made of a small diameter aluminum tube like in Viking. Not a reliable solution in adverse conditions, but Sonnet is a light-duty boat for daytrips or short touring, so I can justify this. Other Tom's boats have a properly shaped HDPE coaming with flat "lip".


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