The solution for most boatyards and diving services is PropSmith, which threads onto the propeller shaft and uses three bolts threaded into holes pre-drilled into propeller hubs to remove and also reinstall high-tech propellers (www.propsmith.com). While a PropSmith for a particular size shaft is relatively inexpensive, under $1,000 for a three-inch shaft, a full set covering all boats exceeds $10,000, which is more than many yards or divers will invest for just an occasional need. Boats that travel away from major repair facilities should consider carrying a PropSmith as part of an on board tool kit. They should also carry spares of non-standard parts, like lock washers used on some Asian or European boats in place of traditional cotter pins. "That's all that holds the propeller on," Daniello says. "You might get by reusing them, but it isn't worth the risk." He also recommends acquiring any other specialty tools needed to do the job, such as thin-walled sockets, which are needed to remove prop nuts on some Italian boats.