I have rigged a 6:1 internal outhaul and it works well but there is a lot of friction when it is eased due to the boltrope in the slot. Would it be advantageous to add slugs to the foot? I can see two potential advantages: 1) less friction in the system, and 2) when reefing, the nettles can be tied around just the bunt of the sail instead of the boom.
Disadvantages: less aerodynamic efficiency?
Two things cause a boltrope (or delrin slugs) in a slot to bind:
1. rough/dirty 'slot'
2. 'fattened' boltrope.
Dirty slot.
The inside of the slot can easily lose its anodizing due to the friction of the sail or slugs. Once the anodizing becomes worn you can easily get oxidation of the aluminum. The second problem is the accumulation of atmospheric dirt. A cleaning/polishing of the slot, especially the 'lips of the slot' lightly with 320 grit sand paper will help ... but once you need to sand and go through any remaining anodizing, you will be committed to always periodically sand the slot. Lubricating the slot with simple paraffin candle wax seems to work best ... just a very light layer (not lumps) will greatly help. I prefer to take a small lump of paraffin, dissolve it in gasoline or naptha-benzene and simply brush it on the 'lips' and also pull a 'wad' soaked with the mixture a few times through the slot. I pull the wad (like cleaning a gun barrel) through a few times until the wad remains 'mostly' clean. Once dry 'then' you can 'spritz' the slot with a DRY teflon spray such as McLube, etc.
For a sail/slot that uses slugs should be cleaned in the same way but for slugs I tend to avoid the 'spray lubrications' as the 'carrier' of the spray 'may' also cause the 'slug' to soften and swell - clean/lightly, sand the slugs and then rub-on the dry paraffin.
Boltrope problems.
Look at the boltrope in its relaxed condition .... if there are 'wrinkles' of the boltrope sheath they usually will have the peaks of the wrinkles quite dirty and 'smeared' with accumulated debris. If so, CLEAN / scrub the boltrope sheath with an INORGANIC cleaner - such as a 'mildly caustic' detergent: diluted sodium silicate based detergent or diluted TSP, etc. STAY AWAY from 'petroleum based' cleaners as they tend to make the dacron swell-up or 'soften'.
Boltropes are usually made of 3 strand DACRON rope. Almost ALL 3 strand rope becomes FATTER and SHORTER and 'stiffer' over time (same thing happens to docklines). Every time you stretch out a 3 strand rope then relax it the rope will 'shorten' and become fatter by a 'teeny' little bit. If the boltrope has become signifciantly 'fattter' it will then tend bind in the slot and then needs to be either replaced (moderately expensive), readjusted for proper length (less expensive) .... or if your are 'daring' - soak the boltope (not the whole sail) in quite warm water in a large bucket with a little bit of liquid laundry detergent, then immediately stretch the boltrope between two 'immovable' objects with sufficient tension to significantly stretch out the rope (but not break the sail) .... and let it *dry thoroughly* (days) under this strain. If you know the original precise dimensions, 'sometimes' you can restore the rope back to its original length *and diameter* --- dont 'overstretch it'.
I avoid using 'spray' lubricants or 'petro based' liquid lubricants which promote softening and swelling of 'plastics' ... I usually will 'rub' dry paraffin on the boltrope sleeve (but sometimes will spray on McLube, etc. but from sufficient distance in an 'attempt' to allow the 'carrier' to 'flash off' or become 'vapor' before it hits the sail).
Note for 'slug' connected sails -
to keep the (luff) slot constantly lubricated, carve a ~1" long piece of paraffin 'slightly' smaller than the diameter of the slot, put it between the topmost slug and the next highest slug .... every time you raise the sail the 'pencil' will lightly rub against the slot and keep it 'slick'. Slugs wear out quickly, especially the 'end portion' of the slot and once they 'lose diameter' they can easily 'toggle' (by just a few degrees) in the slot and begin to act as a 'brake' with point to point contact. So, if the slugs seem to have the area near the 'ends' seems to be worn ... replace them.
(For a luff boltrope in slot configuration, just put a 'smaller wax slug' in the slot before your raise ... and be sure to catch it when you lower the sail.)
Benefits
A well LUBRICATED and clean 'slot' will allow a sail to QUICKLY 'equilibrate' so that when you add/release tension to either the halyard/cunningham/outhaul ... the resultant 'adjustment' and change of sail shape will occur very quickly ... if the b-rope or slugs are binding the change in shape can take a LOT of time to 'equilibrate' until the rope/slugs eventually and finally move to their 'final' position in response to the adjusted tensions !!!!!
approach when I got my C22 was to install a 6:1 low friction outhaul. As luck was in my favor - my experience is that this works and I have enough oomph in the outhaul to make large differences in sail shape.
