I have designed a spreadsheet application that lets me enter table of offset data and it converts all the measurements into new tables that I can use to enter data into my CAD program. It will also scale the dimensions. The scaling is pretty simple, just enter the scale factor and the program applies that to all measurements. So if you want to scale the Ranger from a 15 foot canoe to a 13 foot canoe you just enter the equivalent of 13/15 or .8667.
I did that for the Ranger in Canoecraft. As expected the length is now 13 feet. Also as expected the beam shrunk from 35 1/4 to about 28 1/4 and the depth shrunk from 13 1/2 to about 11 1/3.
I don't know what affect the decrease in beam and depth will have on the stability of the canoe. I know the Rob Roy at 12 feet has similar numbers, but I was wondering about this particular design.
I was also wondering what affect adding additional height to the plans would have and if any one has a suggestion on how to go about that. I think I would like a little more depth, but I haven't been in a canoe in a while and then it was commercial and I really didn't pay much attention to dimensions, so maybe 11" inches is enough for a solo canoe. It would mean placing the seat on the bottom of the boat, but that shouldn't be a problem. I built a kevlar canoe many years ago and it had the seat on the bottom, and was pretty comfortable.
Thanks in advance for any advice, and if anyone would like to see all the numbers, I'd be more than happy to forward a copy to you, just send me your email address.
Scaled Ranger
Scaled Ranger
John Wright
Re: Scaled Ranger
Hi John,
Sounds like an interesting program, great idea and way to compare and change sizes. As regards to solo depth, 11 would probably work but it depends on intended usage for the boat. Tripping or just cruising around the cottage. I think sea worthiness is often overlooked by a lot of canoeists.
The other thing to consider is that length and design play into each other handling wise. A boat like the ranger has lots of rocker already, reducing length may accentuate the effect the rocker has in freeing the ends and making for a boat that turns even more, but which cause tracking to become worse. So if using it on lakes etc for long go straight paddling, that may be a factor. I think you might end up with more of a 'playboat' rather than moving water boat - if you get my meaning. Still, that may be exactly what you are looking for.
There are several guys on here that like to play around with design programs and I know Steve Killing drops by from time to time so maybe one of them might chime in.
Moonman.
Sounds like an interesting program, great idea and way to compare and change sizes. As regards to solo depth, 11 would probably work but it depends on intended usage for the boat. Tripping or just cruising around the cottage. I think sea worthiness is often overlooked by a lot of canoeists.
The other thing to consider is that length and design play into each other handling wise. A boat like the ranger has lots of rocker already, reducing length may accentuate the effect the rocker has in freeing the ends and making for a boat that turns even more, but which cause tracking to become worse. So if using it on lakes etc for long go straight paddling, that may be a factor. I think you might end up with more of a 'playboat' rather than moving water boat - if you get my meaning. Still, that may be exactly what you are looking for.
There are several guys on here that like to play around with design programs and I know Steve Killing drops by from time to time so maybe one of them might chime in.
Moonman.
Re: Scaled Ranger
Thank you for the quick response. It will be mainly used for fly fishing. Even with the reduced longitudinal stability that reduced keel length will cause, it should have more stability and be more comfortable than a "belly boat". Maybe the addition of a small keel at the centerline would help. Don't know, I've designed airplanes before, but boats behave differently, so maybe a little experimentation is warranted.
Might be a good project for this spring.
Again thanks for the quick response.
Might be a good project for this spring.
Again thanks for the quick response.
John Wright
-
Rod Tait
Re: Scaled Ranger
As an avid flyfisher, I have never tipped over in my belly boat nor felt unstable. As a builder of canoes, I have fished from them and would rather use a row boat. If you are alone in the canoe, every small breeze will blow you off course, spin you around and always away from a good "rise"
I think you will find that the reduced beam will make this canoe less stable than original design and certainly not stable enough to stand up in and cast. If your need is shorter, I would leave beam and shape alone and consider just shortening the spacing between forms.
I think you will find that the reduced beam will make this canoe less stable than original design and certainly not stable enough to stand up in and cast. If your need is shorter, I would leave beam and shape alone and consider just shortening the spacing between forms.
Re: Scaled Ranger
Good point. I have never tipped over either.
I never stand up in a boat when fly fishing. At least, not in the recent past. But you have a good point. I'll have to play around with just shortening the distance between stations. But won't that make it, pardon the term, "short and fat"? When we design wing cross sections we worry about a number called the fineness ratio. The ratio between length and width. Changing it has significant impact on the aerodynamics of the wing.
But your point is well taken, I'll take a look and maybe build a model to see what it looks like. Maybe a 1/10 scale would let me see what things look like and maybe do a little testing.
Many thanks.
I never stand up in a boat when fly fishing. At least, not in the recent past. But you have a good point. I'll have to play around with just shortening the distance between stations. But won't that make it, pardon the term, "short and fat"? When we design wing cross sections we worry about a number called the fineness ratio. The ratio between length and width. Changing it has significant impact on the aerodynamics of the wing.
But your point is well taken, I'll take a look and maybe build a model to see what it looks like. Maybe a 1/10 scale would let me see what things look like and maybe do a little testing.
Many thanks.
John Wright
Re: Scaled Ranger
Hi John,
Canoe design has the same thing (typically called length to width ratio) and if you are into airplane design I'm sure you'll be way ahead of most of us. In particular check into block coefficient and prismatic coefficient. If interested, check out John Winters' 'Shape of the canoe'. You can see it here at the bottom of the page: http://www.greenval.com/jwinters.html
I too flyfish from my canoe all the time and as Rod mentioned, I do find my belly boat more stable and wind resistant, esp when compared to being in a solo canoe. But you can't beat the mobility of the canoe for moving around a lake. I've customized my canoe with an anchor system using cam cleats and having the anchor rope descend/rise directly from the top of the bow stem. Very easy to drop and pick up and makes solo fishing a lot easier. I would also take a look at the Bob Special model as an option for your intended purpose.
Moonman.
Canoe design has the same thing (typically called length to width ratio) and if you are into airplane design I'm sure you'll be way ahead of most of us. In particular check into block coefficient and prismatic coefficient. If interested, check out John Winters' 'Shape of the canoe'. You can see it here at the bottom of the page: http://www.greenval.com/jwinters.html
I too flyfish from my canoe all the time and as Rod mentioned, I do find my belly boat more stable and wind resistant, esp when compared to being in a solo canoe. But you can't beat the mobility of the canoe for moving around a lake. I've customized my canoe with an anchor system using cam cleats and having the anchor rope descend/rise directly from the top of the bow stem. Very easy to drop and pick up and makes solo fishing a lot easier. I would also take a look at the Bob Special model as an option for your intended purpose.
Moonman.
Re: Scaled Ranger
HI Moonman,
Thanks for the information. I love my belly boat. Its light, very portable and in the summer a very "cool" way to fish. But as you say, kinda hard to get around a lake with one.
The reason I want to scale them back to about 12 - 13 feet is for portability mainly. 15 feet just seems to be a bit long to just throw on the top of my Explorer and take off to the nearest lake/river.
What I may do is build a 15' Ranger or Hiawatha and see how it works. If its too long I can proceed with the scaling venture again. This will be my first attempt at building this kind of canoe, so maybe that would be a better plan. But I will look into the scaling factors you mentioned, if nothing else I can play with the design on paper a little and see what comes out.
John
Thanks for the information. I love my belly boat. Its light, very portable and in the summer a very "cool" way to fish. But as you say, kinda hard to get around a lake with one.
The reason I want to scale them back to about 12 - 13 feet is for portability mainly. 15 feet just seems to be a bit long to just throw on the top of my Explorer and take off to the nearest lake/river.
What I may do is build a 15' Ranger or Hiawatha and see how it works. If its too long I can proceed with the scaling venture again. This will be my first attempt at building this kind of canoe, so maybe that would be a better plan. But I will look into the scaling factors you mentioned, if nothing else I can play with the design on paper a little and see what comes out.
John
John Wright
Re: Scaled Ranger
Good luck on the project. I think you will find the 15 foot length actually perfect for your needs.
Re: Scaled Ranger
i had to look up "belly boat" to figure out what you guys were talking about... and it was what i was afraid it was. 
you couldn't pay me to fish in one of those things where i fish... bull sharks go way up river into the fresh here.
i went with the bob's special in the standard 15ft specifically for the purpose of fishing and solo car topping. i can't see the length as being a problem, and my car is smaller than an explorer.
you couldn't pay me to fish in one of those things where i fish... bull sharks go way up river into the fresh here.
i went with the bob's special in the standard 15ft specifically for the purpose of fishing and solo car topping. i can't see the length as being a problem, and my car is smaller than an explorer.