The hydraulic headsail furling started to open up at sea one day and, after opening the cap on the furling unit and starting to diagnose the problem, a couple of steel bearings dropped overboard and some of the nylon bearings … Continue reading
Found one! Fortunately we found a spare rib on which to attach the SSB mounting frame. The mix of aluminium and teak mounting points with their varied expansion/contraction in rates in differing temperatures are a concern but the choices were … Continue reading
Validating the fixing needs of the main SSB did not reveal much. Allowing for the 13.5kg unit a free fall drop of 5 metres resulting in a sudden dead stop (no distance allowed for deceleration) requires an overall fittings strength of 1.7 kilonewtons. The issue is then finding the shear capacity of A4 bolts in kN/mm2.
Stainless steel may have a tensile strength of 500 n/mm2 and an M6 bolt should have , leaving aside 1mm for thread, a total load area of 19mm and therefore tensile strength of 9.5kN. Not the same as shear but the load value indicates a level of comfort spread across 4 bolts.
With wiring unwrapped from all that it seeks to cling to, pull down, get snagged on the interfacing of Wotsit A to Wotsit B, C and D may, fingers crossed, be finished. The last job then is to fit the … Continue reading