I have had extensive experience with ocean kayaks and long distance trips on same. My advise is that on a typical mono-hull boat you do not, repeat, do not want the kayaks tied to the lifelines or stanchions . The surface area they present in unacceptable in any sea state. Put quite simply they will tear your lifelines off and take portions of the hull with them. Dealing with problem at sea with endanger the crew and the boat.
I do however believe that sea kayaks make a wonderful diversion for exploring while cruising. If you must take them I suggest you tow them. A small drogue off the stern of the kayak in the form of Clorox bottle filled with water will cause them to track straight and surf down wave fronts safely. Tow the kayak at least one wave “period” behind the mother boats. (when the mother boat goes down a wave the kayak goes down the wave set behind the boat.) The cockpit on the kayak must be enclosed where the spray skirt normally goes, these are available for transporting the boat on top of cars in a upright position.
KEEP A SHARP KNIFE HANDY AND SACRIFICE THE KAYAK RATHER THAN ENDANGER THE VOYAGE OR CREW IF SEVERE PROBLEMS OCCUR.