How it works: The collar position (inboard) comes from the boat — half the span plus 6–8 cm for sculls, spread plus 29–31 cm for sweep, as Concept2 publishes. Taller rowers get a slightly wider span or spread and a touch more inboard. Sex, weight, age group and level then pick where you sit in Concept2’s short / medium / long oar-length band: lighter, younger, older or newer rowers get a shorter oar (lighter load). Treat the result as a starting point and refine it on the water.
This oar rigging calculator tells you where to set the collar (button) on your sculls or sweep oar, and what overall length to set on an adjustable handle. It uses Concept2’s published inboard method, which measures the same way for every brand, and adjusts span, spread and oar length for your height, weight, sex, age group and level.
| Setting | Sculls | Sweep |
|---|---|---|
| Inboard (collar) | 85–90 cm | 113–117 cm |
| Span / spread | 156–162 cm span | 83–86 cm spread |
| Overlap | 12–20 cm | n/a |
| Gear ratio | 2.4–2.6 | 3.0–3.2 |
| Concept2 length, Smoothie2/Big Blade | 281–292 cm | 367–378 cm |
| Concept2 length, Fat2 | 275–285 cm | 362–373 cm |
Concept2 publishes the full method and short/medium/long length tables used here. Dreher ships sculls at a standard 286 or 288 cm with 88 cm inboard, and its sleeve decal reads outboard — so set the collar to the outboard figure. Brača-Sport suggests setting adjustable oars in the middle of their 5 cm range. Croker and WinTech/King provide rigging guides and videos rather than inboard tables, so this calculator uses the generic method and a big-blade length range for them.
Methods and ranges from Concept2’s published rigging guidance; Dreher defaults from its US dealer; Brača guidance from Brača-Sport. Concept2, Croker, Brača-Sport, Dreher, WinTech and King are trademarks of their owners; MultiSwitch is not affiliated with any of them. Starting points only, not coaching advice.
The collar sets your inboard: from the handle end to the blade-side face of the collar. For sculls, half the span plus 6–8 cm. For sweep, spread plus 29–31 cm. It works for any brand of oar.
Indirectly. Inboard mainly follows the boat. Taller rowers usually row a slightly wider span or spread with a little more overlap, which moves the collar out. Weight, age, sex and fitness mainly decide overall oar length — the load.
Outboard ÷ half span is commonly 2.4–2.6 for sculls; outboard ÷ spread is commonly 3.0–3.2 for sweep.
Their sleeve decal reads outboard length. Outboard = overall length − inboard, so line the blade-side face of the collar up with the outboard figure shown above.
It clips on between collar and oarlock and adds 1 cm of inboard, making the oar lighter without moving the collar — useful in a headwind or when sharing oars.
