CT Sailbattens : strong, light, durable carbon fiber sail battens for Superyachts, America's Cup, Offshore Racers, Multihulls, Maxis, Cruisers

CT Sailbattens, manufacturers of carbon / kevlar sail battens for performance yachts

tel : +64 9 810 8406

CT Sailbattens

PO Box 58, Waitakere
Auckland 0660
New Zealand

email C-Tech

Bend Tests: 3-point
How to conduct a 3-point bend test on existing battens

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Bend tests provide a measure of the camber of your batten. There are 2 basic tests required to provide the necessary numbers for calculating camber:

- Self Weight (amount a batten sags under its own weight)
- Deflection (amount of sag using a fixed weight)

By testing your existing battens C-Tech Ltd can assess their shape and bend characteristics before providing your new carbon sail battens.

1. Items required
- 2 equal height supports
- Fishing line or string to use as a horizontal reference point
- 6.8 kg (15 lb) weight

2. Mark test length points along each batten
With the batten lying flat, mark 100 mm from the front end.

Measure the length along the batten to approximately 100mm from the back. To make calculations easier the test length can be rounded to the nearest 100 mm (eg. 4.2 metres, 5.5 metres) as long as there is at least 100mm extending beyond the test length at the back.

Mark the end point and record the test length to be used.

Calculate and mark the 1/4 point, 1/2 point and 3/4 point along the batten (measured from the front mark).

3. Measuring Self Weight
Position 2 equal height supports under the marks at front and back of batten.

Stretch the string-line taut between the marked front and back points.

Measure and record the amount of sag at the marked 1/4 point, 1/2 point and 3/4 point.

4. Measuring Deflection
Suspend a 6.8 kg (15 lb) weight from the 1/2 point marked on the batten.
NOTE: As the batten sags you may have to reposition the supports under the front and back markers.

Stretch the string-line taut again between the marked front and back points.

Measure and record the amount of sag at the marked 1/4 point, 1/2 point and 3/4 point.

5. Calculating bend test measurements
Record figures as shown in the following table to obtain obtain bend test measurements. You can record your measurements directly onto this page, then click Calculate to generate bend test results in the grey-shaded boxes.

6.8kg (15 lb) is the default test weight
Measurements must be in millimeters
Difference = Selfweight (mm) - Deflection (mm)
Front % = ¼ Difference ÷ ½ Difference
Back % = ¾ Difference ÷ ½ Difference
Camber = ½ Deflection ÷ Test Length

Measured Test Weight (kg)
Measured Test Length (millimeters)
	Self-weight (millimeters)	Deflection (millimeters)	Difference (millimeters)
1/4
1/2
3/4

Front %
Back %
Camber %
3-point (Average) EI (nM2)

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