J/70 Owner Guide
Page
© Copyright 2013, J Boats, Inc. All Rights Reserved
34
If you have a bow-‐stop on the trailer, use shorter strap runs (running nearly vertical) over
the boat rather than long diagonal straps through the bow and stern rails. This reduces
the possibility of trailer flex contributing to any excess strain.
Be sure to properly and carefully tie down the keel to the trailer as this component is
independent of the boat and can otherwise bounce on the keel tray. Care should also be taken to
properly protect the trailing edge of the keel inside the keel trunk to minimize movement inside
this area while traveling.
3)
Docking & mooring
-‐ care should be taken to avoid mooring or docking your boat in locations
that can result in the keel being occasionally imbedded in mud/sand/silt when at low tide or low
water. A combination of the keel bulb imbedded with any sort of wave action against the hull
can cause undue stress to the hull and keel structure. The same is true for boats that use special
dockside hoisting systems to hoist the hull out of the water, while the keel remains underwater
and unsupported.
Maintenance Considerations:
1)
Care should be taken to avoid having standing water in the bilge. Not only does standing water
accelerate corrosion of fasteners and bolts over time, it will promote mildew and other
unwelcome growth inside the boat. As the gelcoat/ paint ages in the bilge area, bilge water can
eventually seep into the fiberglass laminate by way of pin holes in the gelcoat and weaken the
fiberglass laminate structure. The
process of hydrolysis
can be initiated in the fiberglass laminate
anytime
there is ingress through cracks in the paint/gelcoat in the bilge.
The process of hydrolysis
is persistent and invisible-‐ it's water that chemically degrades the quality and strength of the
laminate over time.
Bilges (all areas not just the centerline bilge) should be cleaned thoroughly
once per year and then every five years recoated with fresh gelcoat or epoxy paint to ensure
proper protection. In northern climates, water turns to ice in the winter. If moisture gets into
the laminate and freezes, this can rapidly accelerate deterioration in the laminate. The New
Hampshire Materials Testing Labs website (
www.nhml.com
) has an informative article on
hydrolysis, see Newsletter of May 1, 2006.
2)
In any cored hull, take special care to avoid having any fasteners penetrate the inner hull
laminate. Water in the bilge area can easily weep through the fastener into the laminate and
cause core damage. If you need to secure a fitting or wire tie to the hull, the best fastening
method is to glue epoxy coated marine plywood blocks to the hull and then fasten into the ply.
RIGGING
1)
Standing rigging
-‐ The general rule of thumb is that standing rigging (whether wire or rod)
should be replaced every 10 years, unless excess strain due to hard ocean sailing shortens this
life. Fatigue can be in any form-‐ sailing in extreme wind conditions, unnecessary flogging of
loose leeward shrouds, corrosive environment. Any signs of a broken wire strand(s) indicates
immediate replacement is necessary. Otherwise keep a close look out for corrosion or cracking
in the swage fittings and turnbuckle threads. In southern coastal areas, with the high salinity and
year round warm weather, rigging must sometimes be replaced every 5 years. Fresh water
sailed boats will generally have a longer rigging life, but are still subject to fatiguing after years of
stress.
