Many rowing clubs do not have the resources to hire a full time boat technician, but that does not mean that you cannot adjust your rigging and oars to receive the full benefits of having a finely tuned boat. In the following slides adjusting oarlock heights, span distances, oar lengths, and foot stretcher distances will all be addressed. Anyone with basic tool and rowing knowledge will be able to complete these steps.
In order to complete this set of instructions you will need the following tools:
- Tape measure
- A Level
- Crescent wrench
- 7/17" wrench (Ratcheting wrenches work best)
- A screwdriver, the type of screwdriver will depend on your oar sleeves and shafts
- Heat gun (If adjusting oar squareness)
Rowing 101- Rigging Basics was used a source
Step 1: Calculating Distances and Heights
Before you begin to adjust the settings of your boat, you will first need to calculate what heights and distances you will be using. While you can do this by hand, Bio Rowing will allow you to enter your know information and will calculate the most efficient lengths for your crew. This calculator will give you numbers based on wind speed, water temperature, stroke rate, and your rower's average height and weight. The lengths you will need to take note of are the traditional oar length, inboard length, and spread. Write these numbers down and continue to the next steps.
Step 2: Changing Oar Lengths
When changing the length of the oars, it is referring to the total length of the oar, from the butt of the handle to the center of the blade
(Figure 1.) For this length you will use the distance calculated in step 1. To do this loose the screw, and slide the handle either in or out of the shaft. Sometimes the handle is wedged in and must me played with before it will move (figure 2.)
Changing the oar length will allow your rowers to apply more or less power to propel the boat forward with each stroke. A longer oar length will use more force, but will send the boat further with each stroke, while a shorter oar length will require less power, but the boat will not be sent as far with each stroke. A typical oar length will range from 363 to 380 cm.
Step 3: Changing the Inboard Length
Changing the inboard length is much simpler that changing the total oar length. The inboard length is determined by the button location on the oar. The button should be screwed on using hex nuts. To change positions, and therefore inboard length, loosen the screws and slide the button either up or down the sleeve. The inboard length is measured between the outside of the button (the side closest to the blade) and the butt of the handle.
Adjusting the inboard length will have the inverse effect on stroke efficiency. A shorter inboard length will require more power each stroke, but will send the boat further. On the other hand a longer inboard length will require less power, but will not send the boat as far with each stroke. Typical inboard lengths range from 112 to 116 cm, or 30 cm greater than your spread (step 5.)
Step 4: How to Measure for Correct Oar Heights
In order to have a well set boat, a crew must all be able to pull in at the correct height. Many problems with oar heights, both on the drive and the recovery can be corrected by either adjusting the height of the oarlocks, or by repositioning the foot stretchers. The oarlock heights should be consistent throughout the boat, so once they are at a set height, all of the adjustments should come by means of adjusting the foot stretchers.
In figure 3, the oar height is too high, meaning that the rower will throw off the set of the boat if they are pulling in at the correct height. The correct depth, and position is seen in Figure 4. The butt of the oar should be pulled in to the upper rib while the blade is floating in the water. (Note: there should be no pressure applied either up or down to the oar when setting handle heights.)
Step 5: Adjusting Foot Strechers
In order to set the boat correctly, a rower's foot stretchers must be correctly positioned. When positioning foot stretchers, As described in Step 4, move the foot stretchers back if the rower is pulling in to high, and forward if they are in too low.
To adjust the foot stretchers, simply loosen the wing nuts attaching the plate to the boat, and move them along the grooves. The wing nuts are shown in Figure 5. NOTE: The wing nut in the top, center of the foot plate does not loosen. It is to keep the shoes attached.
Step 6: Adjusting Oarlock Height
While the heights of the oarlocks will not help the rowers to apply their power, it will help them to move with less drag through the water. The purpose of adjusting the oarlock heights is to allow the rower to move their blades on the recovery without touching the water. Oarlock heights are typically adjusted by moving plastic spacers, movable or permanent, either above or below the oarlock (Figure 6.) The height of the oarlock is measuring from the bottom of the oarlock to the top of the seat.
The height of the oarlock will allow the rower to pull in higher if the oarlock is higher, and lower if the oarlock is lower. The oarlock height ranges from 11 to 18 cm, but will vary from club to club based on preference.
Step 7: Changing Spread Distance
To change the spread, a rower must first know how to measure the spread. To do this, Place your measuring tape at the center of the oarlock pin and then measure to the opposite gunwale(Figure 7.) After this measure the width of the boat (Figure 8), divide that distance by two, and subtract it from the initial measurement. All spreads on the boat should be the same, as to keep the boat correctly balanced.
By increasing the spread of the boat you will make the boat feel lighter, but the boat will not travel as far with each stroke. The opposite is true when decreasing the span, The boat will feel heavier, but the boat will travel further with each stroke.
Step 8: Changing Oar Pitch
The oar pitch is something that can be very easily changed. The pitch of the oars is a personal preference and will change from club to club. The average pitch will range from 3 to 7 degrees. To change the pitch, simply change the inserts as seen in Figure 9.
Adjusting the pitch will change how much lifting force you apply to the boat. The higher of a pitch you have on your oars, the more force will be applied to push the boat forward rather than up, creating more drag.
Step 9: Setting Lateral Pitch
Setting the lateral pitch of the oarlocks is a very similar process to changing the standard pitch of the oars. A metal pin will determine the lateral pitch (Figure 10.) To change the lateral pitch simply remove the oarlock and spaces, and change the pin that connects to the oarlock.
The lateral pitch of the oars changes the pitch throughout the stroke. So if a lateral pitch of 1 degree is used, 1 degree will be added to the catch, and will decrease 1 degree at the finish.
Step 10: Squaring a Blade
Often times, over time, blades will be come unsquare and not allow the rower to correctly take stroke. To Fix the problem, the sleeve will need to be heated using a heat gun. To measure the squareness of the blade to the sleeve make sure the face of the blade is level, and rotate the sleeve until the flat side of the sleeve is square according to a second level.