J/70 Owner Guide
Page
© Copyright 2012, J Boats, Inc. All Rights Reserved
13
Mast Boom & Standing Rigging
The J/70 mast & boom are built by Southern Spars of carbon fiber and painted black with white limit
marks. The mast, masthead crane and spreaders are also built of carbon fiber and painted black.
The deck stepped mast has a SS tabernacle deck mounted plate with cast aluminum mast foot. The
system allows the mast to articulate outboard in order to be attached, hoisted and lowered to the SS deck
plate while the keel is in its raised position.
The carbon mast includes provisions for three internal halyards (mainsail, jib & spinnaker) including
cleating at the mast base. The main halyard terminates on the black horn cleat to port while the jib and
spinnaker halyards lead to the Harken pivot blocks on the mast with spinnaker to starboard. An
aluminum mast track is provided with two gate options (interchangeable). One option is for use with a
bolt-‐rope style luff on the mainsail, the other is for use with mainsail sliders to keep the mainsail captive
to the mast. Mast is also equipped with two strap eyes at the mast base, a vang lug and a boom gooseneck
fitting.
The J/70 boom is equipped with an adjustable outhaul system led to a jam cleat and lead block on
inboard end of boom, soft attachments for both the vang block and the mainsheet strop, Antal sheaves
outboard for both outhaul and a clew reef, and finally a jam cleat and cheek block for the inboard end of
an optional owner supplied clew reef line.
IMPORTANT! CARE SHOULD BE TAKEN WHEN HOISTING AND LOWERING THE MAST
TO FIRST REMOVE THE VANG LUG AND TO PROPERLY SUPPORT AND PAD THE MAST
AT ALL TIMES IN ORDER NOT TO DAMAGE THE MAST TRACK, THE MOLDED DECK
RISER AROUND THE COMPANIONWAY AND THE SS DECK PLATE.
Jib halyard fine tune adjustment
Unique to the J/70 is a jib halyard fine tune. This is a 4:1 floating purchase system on the port side of the
mast that attaches to a spliced loop on the jib halyard that appears from the jib halyard exit on the mast
once the jib is hoisted. The beauty of this system is that the jib halyard tension can be controlled right
from the cockpit without the need for winches.
Jib Furling System
The J/70 is equipped with the Harken small boat below-‐deck jib furler system. The system includes a
hoist-‐able swivel that rides on the headstay, a top swivel and a deck-‐mounted swivel with below deck
drum. Because the headstay itself (and thus the sail) is what swivels, it is sensitive to halyard tension and
initial set-‐up. The furler is not designed for a partially reefed position so you should plan to either sail
with the jib entirely rolled up or fully unrolled. Please read the complete guide provided by Harken to
best understand the system and how to get the best results from it. For initial set up the furling line
should be rolled onto the drum in a counter clockwise direction.
Cockpit Safety Lines
The safety lines surrounding the J/70 cockpit are built by Marlow Ropes and made from 5mm Dyneema
or otherwise known as UHMwPE. These “soft lifelines” are attached by luggage tagging the forward end
