Rethinking the Grand Canyon Dory.

This is sure to end up under the ugly boat thread, but I don't care as long as it works. Form follows function.
Dories have been running the Grand Canyon for many years. There are a few comercial outfitters that run dory trips down the Colorado every summer. These dories are basically beefed up, oversized drift boats.
I thought it was time to rethink it a bit. I wanted something that did more cuttng and less pounding, when going through waves. I was willing to give up some primary stability for final stability. Flipping is far worse than rocking. I wanted it to be self bailing and took inspiration from comercial fishing vessels and open ocean racers (water drains out the open back). I also wanted it to be easy to get on and off the boat and I thought the best place to do it would be over the stern. Another check mark for the open back. I figured I'd have a floor that sloped down from front to back. I think there is some chance a big wave would wash in and the weight would push the front down preventing the water from flowing out the back. Some aditional drain holes on the side might be a good idea.

 

I have never run the Colorado but have only watched boats run it and watched movies and videos so I am no more expert than you. What I do notice is that the boats often get turned about and having a boat that must face down stream all the time to be safe may not be a great idea. Self bailing is a plus for me on my boats but in the rapids may make for an unacceptable high center of gravity and a tender dory even more tender. A high CG would be the last thing I'd want in a rapids boat. The dories I see running the Colorado are the result of many years of development and seem to do the job well. Deviating too far from what has been worked out as practical and safe may not be advisable.

Pounding should not be an issue in any case as the boats don't go much faster than the current and are often rowed backwards entering a rapid. I know that is what I have done in a canoe in rapids and seldom exceed the current speed except in calm water..

 

I like your idea of self-bailing.
I am wondering about the open back idea?
Rowing backward (facing the bow) to pace the river.
my concern is the waves from behind?
(looking at the drawings).

I would imagine river speed
would part of the consideration as well.

different boats... different techniques.
this is true.
thanks for the thread

DE

 

If the forward motion was stopped by a rock or something, wouldn't it work like a big scoop and fill with water in about 2 seconds or less? Once the back started digging in, it would more or less power itself down and under, like going too far doing a wheelie on a scooter.

 

My whitewater experience is from kayaks and rafts and my rowing experience is from my guideboat which I've used in surf but not rapids so take my opinion for what it's worth.

I don't like the low stern because it looks like it would be easily backlooped by a hole. I like the self draining idea but I think it would be better to drain through scuppers in the sides. You could probably maintain a low center of gravity by having passengers seated close to floor level and wide side decks with buoyancy above the scuppers would ensure the weight was kept centered and help secondary stability.

 

I think you all have valid arguments. I think water coming in the back might be the major flaw with this design. My goal at this forum is to get people to question the status quo. The fact that people have been refining the Grand Canyon dory design for years doesn't impress me one bit. For one, they didn't start with a clean sheet of paper. They started with an existing design. The Wright brothers succeeded because they didn't just follow the designs before them and try to improve on it. They started with a clean sheet of paper. They took a different approach. Look at the twelve meter class. The design was restricted by strict class rules, yet every America's Cup the boats evolved and improved. If there was a dory competition evey four years with a million dollar prize, do you really think Grand Canyon dories would look like they do? I'm positive they wouldn't. Any design can be improved. To think that Grand Canyon dories have reached their zenith and can't be improved would be short sighted. I may not have done it, but maybe one of you can.

 

Have you seen the article in Wooden Boat from April this year about the early Grand Canyon boats by Norm Nevills? Very different to the modern boats but he always chose the safest line and sometimes portaged. Modern boaters tend to want a more exciting line so the boats developed to go through larger features.

 

I'm with you here riverrunner;
having been in similar situation. Drawing on others experiences and ideas
can only help, suggestions good and bad are certainly up for considerations.
I (personally) can only hope to see the final results There's always more than one way to kick the cat as they say.
keep with it mate!

 

I was just thinking about the self-bailing idea.
the idea perhaps of rubber-plugs/stoppers may be a possibility,
giving one the option of when to use that application.
Of course this is dependent on your stern design.
thanks again.
DE

 

There are ways to design for efficient boats using trad methods, but when it comes to rough water behavior, the only way to effectively produce a new and powerful design is to actually build it, get it out in the conditions for which it is was created and wring it out, thoroughly.

This would be especially true for white water boats, such as a Grand Canyon Dory type with a new design motif. Start in the Class 2 and 3 sections and work your way up until you discover what it can and can not do. Massage your design, build the adjustments and do it all over again. There's nothing like the crucible of Class 5 water to forge a very loud ringing in one's ears as to the suitability of a given design. Once you have been blown out of a crappy boat in Class 5, you suddenly get a completely new sense of what it takes to deal with the forces involved.

 

Grand Canyon dory redesign

First I want to apologize to the moderator for not putting this under my original thread, but as usual I'm having some sort of proablem with the server.
Below is a previous Canyon dory design I'd done that is more conventional. It only departs from what you might find on the Colorado today in having two chines instead of one. My design should have better final stability and better maneuverability than the single chine.
I've also made some adjustments to my rear-bailer design. I think this idea may be salvageable. I'm not too concerned with the center of gravity. If you look at current dories running the Grand, they look like they have a pretty high center or gravity too, and my boat is seven feet wide. Yes, it is possible the boat might get turned around in a rapid, but no, you shouldn't deliberately enter a rapid backwards unless you have a desire to hit a rock. And if you do hit a rock (going forward)I think water coming over the back won't be your biggest concern. I think a deck over the rear portion (leaving an opening for water to escape) might solve any issue with water coming in the back.

 

Not to take the thread off topic, but I just wanted to interject and say sorry for whatever issue you are encountering. I'm not sure if it has something to do with the AOL cache you are routing through — it is a mystery why you are able to post a new thread but not reply sometimes as it should be the same on the server-side. I cannot reproduce the issue yet, but if it persists, please send an email to webmaster (at) boatdesign (dot) net with your exact browser and browser version, the exact message and attachments and thread and time where the reply failed to post for you so I can see if I can get to the bottom of what is occurring. Thanks.
(post moved into thread)