Mast Section Stiffness

Tests were undertaken to measure the bending characteristics and weights of various mast sections.  The bending tests were done on spans of just under a metre using calibrated weights and deflections were measured using a dial gauge reading to .01mm. All tests were repeated 5 times and the averages are the figures shown in the Table.  The standard deviation for the tests was under 2%, but it must be expected that some variation will occur between masts of the same type due to material and extrusion variations.

1Maststiffness

EI is a common way of describing a beam or column stiffness, the larger this number the stiffer the mast.  To put it in a more easily understood form the next column shows the load in Newtons (9.81 N= the weight of 1 kg) to cause a deflection of 15mm when placed in the middle of a on a 1 metre span. 
The first two tests were on masts from a 2003 and a 2005 rig acquired with a second hand boat.  Their provenance is not known.  The reason for the popularity of the anodised French sections is evident: they are close to 20% lighter.
The carbon fibre sections cannot be used for IOMs but present an interesting contrast.
Colin Thorne March 2008, revised to add Anodised section 2013


hulls

keels rudders bulbs

righting moment setup

rigs and sails

You are here: Home Rigs & Sails Mast Section Stiffness