Mast step strength
As David noted, most mast steps are through-bolted to the cabin top. In addition, most masts are bolted to the step at the base and the ones that don't (and many of those that do) have an opening in the underside that fits over a short vertical pin or tab on the step. Finally, the tension from four shrouds, the forestay and the backstay provide much more down force than just the weight of the mast.However, I have to admit that my suggestions were based on the assumption that ALL boats have positive connection between the mast base and step, so they could be misleading for someone whose boat is not so equipped. Every skipper should check his/her mast base and step to make sure that they can take towing loads, and if not should select a more suitable location for connecting a towline. Thanks for pointing that out, Tony.PeterH23 "Raven"