I've got more CAD experience in more programs and versions than I'd care to admit. The spec drawings are easy and if it's not overly complex 3D wouldn't be bad either. I'm no raft whiz so I'd probably have to see a sketch of what you're thinking of before I could do it but it wouldn't take long to whip up once I know what you're talking about.
COUNT
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Are the towers too short for rowing too, or can you go taller w/out the blades pulling out of the water when rowing? It may be a seat hight issue too.
If the oar towers are too short I'd go with the rainbow or a custom rainbow w/ a sleeve welded in to hold the oar lock (DRE rainbows are like this I believe), or go with a DRE set up that is more secure and adjustable personally. Those will be a little spendy, but a better solution imo. rowframe.com might be a little cheaper too, or if you want to make a trip to the mountains and bring tubing, fittings and beer we could fab something up in my shop this fall.
Rob - Thanks for the offer! I may take you up on it but am trying to avoid going to a custom setup.
Using the NRS recommended setup on a small raft, the towers are just short enough that when I take the oars out of the water (with my hands forward) and am returning them back to make the next stroke, they bump my knees and there's not much clearance above my thighs to bring my hands back without having the blades drag in the water or come very close to it.
I've rotated the oar towers in slightly so the oarlocks are a little higher, and moved the foot bar forward a little so that my knees are down lower. This makes the system work OK for the time being but isn't ideal.
I've got a potential swap for some 8" towers in the works which I'll probably go through with but I'm just surprised that NRS's "most widely used" frame configuration is set up so that the bottom of the oar lock is only about 4" above the level of the seat.
Thanks again,
-Andy H.
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Hi Andy,
I have 6 frames setting in the garage. Four fit 14'-16' Avons. One fits a 12' vanguard, one fits a 9' mini mee. Three of the Avon frames have 6" oar towers. All three are wide gear frames and take either 9 1/2' or 10' oars. The other one is a day frame with cooler loop and is 2"-4" narrower than the rest. It has 8" rainbow style towers welded in place. That frame works better with 9 1/2' oars. The Vanguard and Mini Mee frames both have 8" oar towers using 8 1/2' oars on the Vanguard and 8' on the Mini Mee.
Playing around with a Revolution that I converted into a cat, I found that oar length and tower height go hand in hand. I'm guessing this frame is for your 12' hyside? If so, I'd suggest 8 1/2' oars and the 8" towers. If you care to borrow a some oars and try out the different lengths, PM me and we can work it out. If I can get over this cold, I'll be at Pumphouse this weekend.
Building frames, I've messed with this a lot. Here's a quick breakdown.
The variables are: frame width, the freeboard of your tubes above the water, oar length, seat height and angle, along with tower height and angle. Less obvious is the height and position of the footbar, which affects the height of your knees, and how close it is to the seat (i.e. are your legs nearly straight or bent during a stroke?)
Sketching a diagram can help you isolate the problem. But definitely look at your footbar height and leg extension before changing the tower height.
Rather than tweaking one variable a lot, it often makes sense to shift several of the adjustable factors in the direction of comfort.
Lots of good options have been posted here. I work at Down River Equipment and we also have an option. We use Hollaender fittings for oar tower bases. Hollaender makes a cross fitting that will fit an NRS frame and receive our oar tower (which is a larger diameter pipe). We cut the fitting flush on the bottom and tap in a new setscrew hole. Our oar tower is 11" tall. We make it tall, knowing that people can cut it down to the needed height. The aluminum pipe can be cut with a hacksaw or chop saw. We don't have a good picture on our website, but give us a call and we can give you any information that is needed.