“Rigging”: is the term used to describe the determination and subsequent adjustment of the outrigger height, pitch (oarlock face inclination from the vertical), spread or span (distance between the pins in sculling or centerline of the boat to the centerline of the pin in sweep rowing), shoe location (horizontal, vertical and angle), oar length and collar location as well as other adjustments such as boat trim and blade angle at the catch and finish position. The rigging objective is to adjust the boat to comfortably fit the rower while maintaining maximum efficiency of the rowing stroke. 

 

Height Adjustment and Height Measurement

 With a new boat purchase, the height adjustment is usually done by the builder starting with selecting the right size to hull for the intended crew. If this is done correctly the mid-point of the oarlock will be about 220mm to 240mm or 9 ½” off the surface of the water. This general dimension is however difficult to measure so we instead measure from the reference point of the lowest point of the seat (between the seat holes about ½ way from front to back of the seat).

 

On each pin are a total of 8 (sweep) or 16 (sculling) 1.6mm black plastic washers which are used for fine-tuning the height and adjusting the differential distance of the starboard over the port oarlock height. A normal setting would be about 160mm +/- 15mm (6 ½” +/- ½”) from the lowest part of the seat. For scullers, the oarlock height of the leading hand, which will be closest to you, should be about 6 or 12 mm (1/4″ to ½”) lower to provide some knuckle clearance. For sculling novices start with 12mm. or more clearance and as your technique improves, decrease the clearance. For sweep rowing, the height will be about 170 mm +/- 15 mm from the lowest part of the seat.

 

Using Special Tools to Measure Symmetry & Relative Height of Riggers/Locks

 To measure the height, place a straight edge across both gunwales and measure up to the lower inside midpoint of the oarlock and down to the lowest part of the seat. This assumes that the plane of the gunwales and seat tracks are parallel side to side. If you have some doubt check with a level alternately placed across the tracks and the gunnels on the straight edge. If the level shows a difference, you will have to place an accurately parallel riser to support the straight edge above the gunwales because the plane of the tracks is your true point of reference when rowing. Shown in the above picture is a handy tool that helps define the reference plane by registering off the tracks to indicate the relative height and symmetry of identical parts of each rigger or lock. When finished adjusting be sure to tighten all the fasteners holding the rigger assembly together firmly.

 

Pitch: Pitch is the measurement of degrees that the face of the oarlock is inclined from the vertical. Pitch compensates for the flexibility of the oar/rigger system and the imbalance of forces resulting in the blade attempting to dive. The result is that an oar with too little pitch will go deep and be difficult to extract at the end of the stroke. Because the pitch required is dependent on how stiff the system is you must estimate how stiff your equipment is as a starting point. Many years ago when all boats and oars were made of wood we used about 7 – 8 degrees of the pitch with some in the oar and some in the lock. In some countries like Germany that is still the case. Today with the stiffer composite boats, carbon oars, and riggers, the pitch of 4 degrees is molded into the face of the oarlock and the pin that the lock swivels about is set at zero degrees in all directions. If the oar, scull, or rigger is constructed correctly all the extra pitch bushings except for the 4-degree pair that comes with modern oarlocks are seldom used. Most oars and sculls are manufactured well within ½ degree of 0-degree pitch, except those built for the German market which uses 3 degrees. Carbon tubular riggers have pins set at 0 degrees with pitch inserts used to decrease the molded-in 4 degrees to 2 or 3 degrees. This is because the system is very stiff. On the other hand, a recreational or club single with a wing rigger may use pitch inserts to increase the pitch to 5 or 6 degrees. To determine if you need to correct pitch you must row the boat and observe how the oar tracks through the water. Assuming that you row correctly and have the oar seated against the lock face the oar blade should be buried completely and stay at a constant depth and come out cleanly at the finish. If the result of a test row indicates a pitch adjustment then try different degrees of pitch inserts in pairs and repeat the test to see if it makes a difference.

 

Three Types of Pitch Gauges

A pitch gauge is used to check if the riggers have been manufactured correctly or if anything has moved. A pitch gauge is a bubble-type inclinometer. Many types are available and they all work the same way. With the boat strapped down firmly in stretchers, the movable level of the pitch meter is set to level in the bow to stern direction using either the gunnels or the bottom of the hull near the midpoint.

 

 

 

 

 

Strapping the Boat Down Firmly

 

 

 

 

 

 

Using a Pitch Gauge to Level the Boat in All Directions

Once the bubble is set to indicate 0 degrees the pitch gauge is then placed 90 degrees across the tracks and the boat adjusted so that you now have a 0-degree reference plain in all directions.

 To set the level in the fore/aft direction (i.e., bow to stern) do not use the seat compartment because if may have a built-in incline. Use the gunnel or the bottom of the hull directly under the mid-point of the tracks.

 

Leveling the Boat in the Fore-Aft Direction – Leveling the Boat Side-to-Side

 Once this reference plain is established the pitch gauge is moved to the pin or the back of the lock. If the concentric 4-degree pitch insert set is used (which usually is the case), by rotating the pitch gauge 90 degrees the pitch can be checked to see if the pin is vertical in all directions, which it should be. There is another type of pitch meter, which relies on conical pins that fit top and bottom into bolts with conical depressions machined into the hex head center. Using this tool once the boat is leveled it is extremely easy to set pitch so that the pin is checked for being at 90 degrees in all directions to the reference plain without taking the lock off the pin.

 

Using the Pitch Gauge with Special Bolt with Conical Indents

Once it has been determined that the pins are at 90 degrees to the reference plane, or adjusted so that they are, then pitch-bushing pairs can be used to adjust the pitch. To do this the lock must be removed from the pin. Select 1 pair of the 4 bushing pairs: 4,4 degree, 5,3 degree, 6,2 degree, and 7,1 degree. The pairs are identified by the molded-in numbers at the top of the bushing. When inserting the bushing into the lock note that that the bushing must be reversed top and bottom to get the proper angle. After changing bushings be careful to keep the same number of washers over and under the lock as before so that the same height and clearance left over right is maintained.

Rigger Spread or Span: Spread is the distance between the centerlines of the lock pins of sculling boats. Span is the distance between the centerline of the boat and the centerline of the pin and sweep boats. For sculling boats, the spread ranges between 156 and 163cm with most common being 160cm. Sweep boats will range between 81 to 86cm. To assure equal leverage a measurement from the port side track to the starboard lock and vise-versa is made. The actual measurement number is not noted, but must be identical at all positions, both port and starboard so that the boat will pull straight.

 

Checking the Spread with a Tape Measure and Related Measurements

 Measure the pin-to-pin distance from the center-line of each pin to one another and confirm the placement of the decal, which is 1/2 the spread distance.

Also, measure the distance from the centerline on each pin to the outside edge of the opposite track or opposite gunnel. Also, measure the centerline of the pin to number clip to compare fore and aft dimensions from side to side. You can tape, the tape-measure end into the number clip slot, to make this measurement done more easily.