Yacht Aditi

Getting our bearings

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 were seen to have been crushed. Now carrying vital spare bearings, some of which need fitting immediately, as the headsail furling grease had dried out at some stage allowing some balls to drop over the side when the bearing was first loosened. The bearings are a 50/50 mix of 6mm 316 steel ball bearings with a crush rating of 2,040kg

Spare Ribs?

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 few: There is plenty of space and cool air around the SSB unit which can operate at 125 deg centigrade

1,700 Newts

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

The weekend? A complete bender!

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 14 kilo Icom ‘briefcase’ somehwere cool, near the chart table, near the power source and away from anything else that dislikes heat. Add to that the momentum that this will gain under movement and it turns into a structural engineering problem. The process of elimination begins – can’t drill here, not under the freezer, too low in the bilge, too