Mesh nets are made from woven and knitted materials that are the most
comfortable of all netting products. All mesh nets are cut to shape
and finished with a sewn on border for attachment to the boat. Because
of this they can be made to fit a wide variety of shapes with lots
of
attachment options. The borders on mesh nets fall into 2 general categories;
tensioning, and non-tensioning. The different meshes have limits as
to where and how these different types of borders can be used and still
obtain a good fit with acceptable tension.
Border Type Limitations
The simplest way to make a net is to have a tensioning border like
grommets with lacing line, on all sides. By using a non-tensioning
border,
like boltrope inserted into a track, the amount of lacing can be reduced
and the lacing gap eliminated on that side. The following paragraphs
describe the minimum number and orientation of tensioning sides for
each of the meshes.
The Woven Polypropylene Mesh, due to its wide width and ease of fabrication
is the most versatile and can be made with only 1 tensioning side.
The
remaining 3 sides can be non-tensioning. It usually works best to tension
from the widest side. With 2 non-tensioning sides Polypropylene Mesh
can be made to fit with the tensioning sides opposite or adjacent of
each other.
The Square Hole Mesh is also a woven product, but because it is available
only in a relatively narrow width (70") the Square Hole Mesh
will need to lace on at least 2 sides and they should be adjacent
of each
other.
The Coated Polyester Mesh is available in a larger width, but because
it is a knitted mesh it will need to be tensioned on at least 2 sides.
If it is only tensioned on 2 sides these sides should be opposite each
other.
Mesh Net Border types
Tensioning Borders
Grommets laced to attachment points on the boat are the most commonly
used method of tensioning mesh nets. Typically we use #4 nickel plated
grommets with spur washers set into a stiff reinforcement. The key
element in supporting the net with grommets is to disperse the loads
from the
grommets evenly into the netting. to accomplish this we strongly recommend
spacing the grommets no more than 6" apart.
Wrap around grommets, where the mesh wraps around a beam on the boat
and grommets along the edge of the wrapped mesh lace back to a second
row of grommets under the net, can be used to tension the net without
a lacing gap.
Pipe Sleeves can be used as a tensioning border with lacing points
further apart than 6". A rigid rod or tube is inserted into the
sleeve and the lacing line laces around the rod through cutouts in
the
sleeve. This type of border places the loads entirely on the stitching,
but we always cover this with the second ply or a separate seam cover.
This works well on straight sides but not on curved sides.
Webbing Tabs sewn to the underside of a reinforced border to be laced
to the boat are another type of tensioning border. Usually a strong
tube webbing sewn in a V shape completely under the border so the webbing
is not exposed. This is the lightest tensioning border but seldom
used
as the webbing can chafe and the stress is entirely on the exposed
stitching holding the tabs.
Non-Tensioning Borders
Boltrope borders have a rope sewn into the edge that is then inserted
into a track attached to the boat. It is important here to match the
proper rope size with the track Inside diameter so that the rope does
not pull out. This is probably the mos common type of non-tensioning
border. Mast Section type crossbeams can usually accept a boltrope
or we have 2 types of aluminum track available that can be attached
to
the hulls decks or beams around the net opening.
Cable Sleeves can be sewn into the net to accept a cable that spans
the edge of a net opening. Cables should be used only if there is
no
solid structure to attach the net to as they will reduce the firmness
of the net. Our cable sleeves are curved to match the catenary curve
of the cable under tension. It is not desirable to have more than one
cable side on a net as it is difficult to get a good fit and tension
the net. Stainless Steel Cables should coated or run through plastic
pipe to avoid chafing of the net.
Bar Sleeves are large sleeves sewn into a net that fit around a beam
attached to the boat. In order to install this at least one end of the
beam must be removable to insert the net onto it.
Unsupported or Self Supported borders can be used on smaller nets
or in corners or cut-out areas of larger nets where their is no structure
or hardware to attach to. A strong polyester webbing is used in the
border and the net is cut with a large catenary curve. This webbing
becomes
similar to a cable, and like cable the loads at the ends of this side
will be much greater than those along supported sides. The corners
of
this border should be laced to strong, through bolted attachment points.
Obviously this type of attachment used to support an entire side of
a net will offer less support, and the net will not be as firm. However
if the net is not expected to receive much traffic this can be a more
economical solution than a cable.
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