Trellis System

Trellis System

Trellis System

Field Layout (Example shows 3 tunnels together)

NB

TU

NN

ELS

RU

N T

HIS

WA

Y

Trellis System

Perimeter Anchors

1.6m Anchors must be drilled in-line with the cable from the top of the 60mm

Leg. To achieve this, the anchor must be drilled at approximately 45 degrees.

If using a 2.25m trellis height, the anchor point should be 2.25m from the

60mm Leg. If using 2.75m trellis height, the anchor point should be 2.75m from

the 60mm leg.

DO NOT:- Drill the Anchors vertically or drill a hole to put the anchors in to

(unless you want to concrete them in...)

2.25m with 2.25m legs,

2.75m with 2.75m Legs

Trellis System

At the end of the leg row, the 1.6m Anchors are drilled INSIDE the end of the

tunnel, between the first two smaller anchors.

This leaves a clear headland. The 1.6m Anchor here, also needs to be drilled at

45 degrees.

Tip- Drill all anchors before you start standing legs, this makes it easier to

move around the field.

Internal Anchors

The smaller Anchor is the same unit for

the 40mm and 60mm legs :-

It is designed to be drilled with a normal

tunnel leg drilling machine. It is

important to remember when drilling the

anchors, they must account for the

gutter in the tunnel legs.

1.1m from Small Anchor

(Halfway between the first two anchors) 1.6m Anchor

Trellis System

It is vital to understand the importance of accurately drilled legs for this

system to work.

It is important for the leg to slope with the field, but also for this slope to be

in a straight line.

We recommend a minimum slope of 2%, even on flat fields... To create this the

anchors at the base of the field may need to be drilled more deeply than those

at the top. But, those at the top should never be drilled less deeply than the

standard 75cm drill depth

It is important to understand also, that we recommend a maximum distance

along the fall, in any one direction of 50m, before an interim down pipe bracket

to remove water from the structure.

Field conditions are rarely flat, even if they are level. It is best to ignore the

small variations in topography, while at the same time working with the larger

ones.

See Diagram Overleaf:-

Use a Builder’s Brick-Laying line to set the anchors in a straight line (Braided

Nylon is best, definitely not a heavy rope as it will curve under it’s own weight)

This works best over a section of 10 legs. At 2.2m spacing, the height

difference between Leg 1 and Leg 11 would be 2% of 22m, ie 0.44m or 44cm.

This is most simply checked with a water level :-

A translucent tube with water inside to get a level-line,

and measure from this.

If you are in any doubt, please ask for Technical Support.

Trellis System

Trellis System

Legs

On a sloping field, legs of the same length as the trellis height will have been

supplied eg, 2.25m legs for 2.25m trellis height.

If building on a flat site, longer legs may have been supplied to allow trellis

height to be maintained, then, anchors need to be drilled more deeply to create

gutter fall, eg, 2.75m legs allow for a MINIMUM trellis height of 2.25m with a

2% slope over 25m in any one direction.

60mm legs are used on the perimeter leg row and the first two legs in every leg

row.

Each leg must be bolted to it’s anchor and leg top.

NB, Mount all the Leg Tops in the same direction, ie with the mounting bolt

on the same side, across the whole field, this will make it easier to run

cables later.

60mm Legs on perimeter lines

40mm Legs on internal lines

60mm Legs at First 2 and Last 2

positions

Trellis System

End Kits

The Trellis System End Kit is always built on 2.2m leg spacing.

The First two legs are 60mm diameter, between these are 2.2m Telescopic

Struts, comprising a 35mm (male) and 40mm (female). They are mounted on

clamps on the legs, in an “X” formation.

Trellis System

Ensure the legs are vertical, and using the pre-drilled holes (in the 40mm

section) as a guide, drill through the 35mm tube, thus setting the length. Insert

the bolt provided and tighten in-place.

Between the first two legs, there is also a 1.5m telescopic Strut, again,

comprising 35mm (male) and 40mm (female) sections. These are fitted in the

same way as the “X” strut, but mounted HORIZONTALLY b etween legs 1 & 2.

Note how the telescopic strut connects to the Termination leg, this allows use

of the Down Pipe.

Hoop Struts are 2.5m and 2.2m long.

2.2m struts go at the apex of the tunnel, between hoop 1 & hoop 2 then between

hoop 2 & hoop 3,

The 2.5m struts are fixed in to the hoops as shown on drawing

1.5m Telescopic Strut

mounted horizontally

2.2m Telescopic Strut

mounted in “X”

Trellis System

Installing Leg Row Cables

Installing the leg row cables along the leg rows allows the legs to be held

strongly, making it easier to put the hoops on.

Run out the cable from one end of the tunnel, from the drum, without it

twisting, then cut to length (this can easily be done with a sharp chisel) :-

The cable runs through the clamps on the leg tops (to left or right, but the

same side for the whole leg row)

Trellis System

Tensioning Cables

Secure the cable to the “Cable Tensioner”, which is itself connected via the D-

Shackle to the 1.6m Anchor

The tensioner has an integral ratchet to help tightening but it is important to

use the Trellis Tension Kit to pull the cable REALLY TIGHT:-

With the cables tight, check each leg for vertical and tighten the lower nut,

this will leave the upper nut and gutter clamps loose, ready to have the gutter

installed later.

Hoops and Top Bracing

With the Legs, Leg Row Cables and End Kits in place, it is possible to start

installing the Hoops and top Bracing.

Start at one end of the field (if the field slopes, start at the lower end).

Ideally, you would install all the hoops then the top rail. It may be that the

hoops will not stand straight, in which case, stand a few hoops on the legs and

install one piece of Top Bracing. If you start from one end, with a fixed End

Kit, the Top Bracing will support the hoops.

Trellis System

Top Bracing

The Top Bracing is clamped to every hoop continuously, through the centre of

the tunnel at the top of the hoop, using twist droppers to give space for the

polythene to be tensioned by the ropes. The twist dropper is attached to the

hoop by locating a bolt through the two halves and attached at the other end to

the top bracing with a second bolt, both supplied.

When positioning the Twist Droppers, pull a tight string along the top of the

tunnel to ensure the rail will be straight.

The lengths of top bracing are fixed together with joiners.

If a joint in the rail falls immediately under a hoop, simply cut the one rail short

so the joiner is just to one side of the hoop. NEVER leave an unconnected

Hoop/Rail.

Gutter Installation – See 4 Series Gutter Manual Section

2.2m Struts Twist Dropper

Rail End Clamp Rail Joiner

Trellis System

Cross Cabling

Tip - After the cross cables are installed, it is more difficult to move

large machinery within the tunnels, so plan through this first.

Cross cables are installed all the way from one side of the block to the other

side, similarly to the Leg-Row cables. At the legs, this cable is passed through

the grips on the 10mm bolt :-

At the Perimeter 60mm posts, the cable passes through the post, but first the

“Trellis Cable Sleeve” must be installed through the Post and the Leg Top :-

Bend down,

with hammer

Cross Cable

Leg Row Cable

Trellis System

BEFORE tightening the cross cables, it is ESSENTIAL to install the Anchor

cables. These run from the top of the 60mm Perimeter leg down to the 1.6m

Anchor.

Use a single length of 6mm cable and create a loop at each end by using the

6mm Cable Grips (2 per loop). One loop connects the Cable to the Anchor,

When the cable is finished, it should hold the 60mm Perimeter Leg vertical, so

it is normal to install the Anchor Cable slightly shorter than needed, to allow it

to settle.

When tightening the cables, ensure the

Perimeter Leg remains vertical. Pull the cable

with the Cable Tensioning Kit as before, and

complete with the ratchet Tensioner.

NOTE :- It is important to bend the end of

the cable sleeve over, this prevents it falling

out, and more importantly, prevents the Cross

Cable Chaffing on the Sleeve end.

Anchor Cable

Cross Cable 2 Cable Grips

at each end

Trellis System

Mid Support System

Some heavy crops require additional support along the centre of the tunnel.

Although this can be done with timber poles, the system may have been

specified with steel. If this is the case, mark-out the positions for the Ground

Spike at the same time as marking the anchors (see Field Layout). The spike is

not drilled in to the ground, but rests on top, with the Support Plate.

For tunnels on level ground, where the legs are drilled more deeply to create

gutter slope, some Mid Support Poles may appear too long. Simply, cut the pole

to length or dig a small hole to allow the plate in to the ground. The Cross Cable

must run in, as close to a straight line, as possible, all across the field.

At the top of the 40mm Mid-Support Pole, is the Cable Assembly Unit

(TA00073). This is connects the leg/pole to the Cross and Mid-Support Cables

Trellis System

Item Description Quantity per Unit

1 M10 Hex Nut 4

2 Washer, Dia.44mm 1

3 M10 x 50 Hex Bolt 1

4 Washer, Dia.34mm 2

5 M10 x 100, Eye Bolt 1

6 Washer, M10 1

7 Cable Grips TP00337 4

To terminate the Mid Support Cable, use a 60mm Perimeter Leg and large 1.6m

Anchor. The Leg must have the addition of a Cable Assembly Unit, 60mm

TA00092. This allows connection of the Mid Support Cable to the Cross Cable

and the 60mm Leg, but it also has a plate to protect the Mid-Cable from any

sharp edges on the Leg:-

Trellis System

Item Description Quantity per Unit

1 M10 Hex Nut 5

2 Washer, Dia.64mm TP00339 1

3 Cable Grips TP00337 4

4 M10 x 50 Hex Bolt 1

5 Washer, Dia.52mm TP00338 2

6 Eye Bolt, M10 x 100 1

7 Eye Bolt,M10 x 30, TP00382 1

8 Flat Plate, TO00383 1

9 Washer, M10 XL Plain 1

Even if the Mid Support Cable is not installed, use the extra 60mm Perimeter

Legs on the penultimate Cross Cable to prevent that cross cable moving

sideways under load.

NOTE -Any horizontal trellis wires (running along the tunnel above the

trellis system) should be fixed to EVERY Cross Cable, this can be done with

small grips/clamps or simply by twisting the support wire around the Cross

Cables. This helps spread the load and makes the structure stronger.