I appreciate it!!!
I'll try to answer your questions:
What tube diameter is your boat? Will these fittings work on a range of tube sizes, or only on your size tube?
They will fit all tube diameters. When designing the fitting, I made sure it would fit all the advertised tube diameters I could find, from 17 to 24".
I am thinking those tubes need chafe protection, those snap pins might be a pain catching on things when you really do not need the extra drama; in a flip situation for example. I really like your choice of the NRS towers due their ability to take severe hits without bending or breaking something but I am wondering about the oar length/angle/stroke geometry with the locks set out off tube center.
I was concerned about the chafing on the tubes also, and made a call to Aire (raft is a Tributary), and they assured me that it wouldn't be a problem. They said worst case the outer skin could be worn through, and it would still hold air, because of the bladders. According to them, the (Real) Aire models don't even really have a chafe strip, the chafe area on top of the tube is just made with the heavier PVC material used on the bottom of the tubes.
The snap pins could be replaced with a bolt and acorn or nyloc nut, but this would add considerably to the breakdown time. When the side decking is in place, it actually covers up the snap pins, so it would be hard to accidently get attached to them, but I hear what you are saying.
The geometry actually comes out really close to 1/3in 2/3 out with a 9' oar. (78" between locks, -4" gap between oars, = 37", x 3= 111, which is fairly close to 108") I came across a sweet deal on some factory rope wrapped Cataract oars, but I think I am going to be wishing I had bought some 10 footers.
I like the simplicity of the NRS oar towers, but was very disappointed with a (HUGE) drilled clearance hole for the oar lock shaft. I am going to have to do something about that......I've got some ideas.....
Do you have any bright ideas to hold down your dry boxes? I'd like to get away from camming mine down and having to undo 2 straps and the latches to open them.
I am working on something for the side boxes, as I want to be able to open them easily while underway, but haven't finished it yet. It's really simple, I'll post some pics when it's ready.
I figured out the pricing for the fittings, plus a list of items that would be required to build a 4 bay frame:
8 Double Fittings $78 $624
2 Single Fittings $42 $84
18 U-Bolts $2.50 $45
10 Snap Pins $2.50 $25
8 Frame Plugs $1.50 $12
45ft. 1.25 Anodized Pipe $4 $180
NRS Deluxe Footbar $119 $119
NRS 8" Oar Stands $89 $89
Some items could be added/replaced that would change the overall price, but this should be an honest ballpark.