Stretching A Bob
Stretching A Bob
I'm all set up to build a 15' Bob Special. Molds are mounted on strong back. Went yesterday to pick-up cedar- Going to mill my own strips. Couldn't get any 16' lengths all they had was 17' lengths. So thats what I bought. Now I'm thinking I should just build it 16' long rather than waste the cedar. Pretty sure I read somewhere the moulds had to spaced an extra 15/16". Is that it or is there more to consider. This is my first build.
Ain't none of us as smart as all of us.
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Glen Smith
- Posts: 3719
- Joined: Sat May 08, 2004 9:08 am
- Location: Baie-St-Paul, Quebec, Canada
Thanks. Would a been too simple to look there. I'm afraid I might be jumping too quickly into this decision to go 16'. Are there any concerns. For practical use a 16' is more suitable to me. But it has been about building a canoe not practicality. Thanks again Mike
Ain't none of us as smart as all of us.
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Glen Smith
- Posts: 3719
- Joined: Sat May 08, 2004 9:08 am
- Location: Baie-St-Paul, Quebec, Canada
16' Bob's Special
This info is extracted from the "Choosing A Design FAQ":
Q I recently purchased plans for the 15' Bob's special. On the plans I see that it can also be built in a 16' version. Can you inform me in detail the effect of going to 16' will have on performance.
A The overall weight of the boat should only change by the ratio of the length, since the width and height are not changing. Therefore if a 15 footer weighs 50 lbs a 16 footer should weigh 54 lbs.
Amazing as it may seem, the length of the boat does not affect the stability. If the beam and shape along the length stay the same, the transverse stability is unaffected. The only error in this thinking that a mathematician would argue is that the longer boat will float a little higher and therefore the stability will be reduced, but it is a small change and the Bob's Special has a comfortable stability. (The 16 footer will float about 1/4" higher with the same load).
The displacement of the boat will also change in proportion to the length. If the maximum optimum capacity of the 15 footer is 450 lbs then that increases to 480 lbs. But that might give you the impression that there is more accuracy to those recommended capacities than there really is - they are a subjective range of sensible capacities.
Viking,
If I were to build only one canoe, I'd probably choose the larger 16' version, the reason being simply that more gear can be held in the larger hull. I find 15' hulls great for going solo, and light on shorter tandem trips, but space is limited if more gear needs to be taken. Your needs might be different, still, I'd say for most paddlers a 16' hull is the more versatile choice.
The 16' Bob's will probably be slightly faster than the 15', especially when loaded down with two people and gear. Straight-line tracking will also improve, but turning capability will not. Rate of turn when going light and solo can increased by kneeling into the tumblehome and leaning the Bob's over... it's been awhile since I paddled a Bob's but IIRC, it performed well when leaned over if more turning capability was needed.
Anyway, good luck!
If I were to build only one canoe, I'd probably choose the larger 16' version, the reason being simply that more gear can be held in the larger hull. I find 15' hulls great for going solo, and light on shorter tandem trips, but space is limited if more gear needs to be taken. Your needs might be different, still, I'd say for most paddlers a 16' hull is the more versatile choice.
The 16' Bob's will probably be slightly faster than the 15', especially when loaded down with two people and gear. Straight-line tracking will also improve, but turning capability will not. Rate of turn when going light and solo can increased by kneeling into the tumblehome and leaning the Bob's over... it's been awhile since I paddled a Bob's but IIRC, it performed well when leaned over if more turning capability was needed.
Anyway, good luck!