For those convinced that the way to go is to use a Tackle on the end of the main boom, then I suggest that the answer to your concerns about the strength of the topping lift is to renew it with rope of a higher breaking strain, rather than to incur the considerable additional time delays of going forward to detach main halyard, holding on to it whilst dropping boom to deck, detaching topping lift, securing it somewhere clear of the action, attaching main halyard to boom end, all before attaching your Tackle...
For example, 6mm dia Standard Marlow braid has an"average" breaking strain of 900kgs, so an SWL of <200kgs, perhaps only 2x the weight that you might be trying to lift, & perhaps not much of a safety margin in the event of snatch loading as the boat rolls...
But if you were to replace it with Marlow Double Braid you'd almost double that factor to nearly 4x, and if you were to select from Marlow's Excel dinghy range you could increase the average breaking strain in 6mm dia to as much as 3.5 tons! so an SWL of say 700kgs or a factor of 7x - my point being that the dia need not be a limiting factor, whichever brand of rope happens to be your preference, only the price per metre that you are prepared to pay for it....
For the moment I'm sticking to my previously described preference for keeping the main hoisted and using the Spinnaker Halyard + hand hauled Tackle [subject to the same caveat about upgrading the SWL of the Spi halyard] because most of the time, the Spi Halyard is not in use, & if the Spi is up, it has to be dropped before MOB recovery anyway, + all onboard action can take place adjacent to the shrouds, where the side deck space is clear, unlike the cockpit coaming, and the shrouds provide additional handholds for the recovery crew.
But whichever halyard is your preferred choice, don't forget the UV degradation factor, and renew it regularly.
But, thank goodness, all this is just my "armchair theory" - what say others?
Geoff Sheddick
Parker 27/146 "Stroller'
Geoff Sheddick
Parker 27/146 "Stroller'