J/70 TECHNICAL BULLETIN
October 25, 2012
To: J Boats Dealers
Important Service Notice:
J/70 Keel Crane Line
There has recently been a failure of a J/70 keel crane line.
J Boats, CCFC and John Fox (J/70 structural engineer) are reviewing the cause and any measures that
may be required to minimize the likelihood of a future occurrence. The standard lifting crane and
Dyneema line (5,194 lb breaking strength), have a significant safety margin to handle the 630lb J/70
keel, whose load is reduced 50% with the 2:1 arrangement of the block. Chafe appears to be the most
likely cause in this case.
While the discovery and solution process moves forward, dealers and owners can take immediate pro-
active precautions while lifting or deploying the J/70 keel to insure trouble free operation.
1) Check for chafe on the lifting line, particularly in the area it enters the crane (when keel is nearly or
fully hoisted). This is the area most susceptible to chafe if the following precautions aren’t followed.
2) Before and during all lifting operations it is very important that the keel crane aligns fore-aft with
the top of the keel (not angled off to port or starboard) and matches the centerline of the boat as closely
as possible.
