Multi-hull Trampoline Installation Guide

Fastening systems

There are many ways to install trampolines. These vary from one boat to another. If we often wonder whether a net, a fabric, or a strap will hold or not, it should be noted that these are held up by the boats attachment system, and so consequently by the boat itself.

Our profession deals with the textile or ropes, and the attachment system linked to the trampoline. However, the anchoring points on the hulls, beams, deck, and any other parts of the boat that will hold the trampoline in place should be checked regularly. And no one knows a boat better than its skipper or owner, down to the slightest detail.

Different fastening systems

1 - Aluminium rails

Some boats have aluminium rails that are riveted, bolted, or screwed on to the hulls and / or the deck by the coach roof. In this rail, we can insert a sewn or welded bolt rope on the trampoline, a PVC rod in a cover, or slides that can be laced to the trampoline.

2 - Bar or tube frames

We can also find systems made up of stainless steel bars or aluminium or wooden tubes that are bolted in such a way that a gap remains between the trampoline and the hull or deck, thereby forming a framework on which we can lace a rope or other lacing system.

3 - Dead eyes

Often these are staples or screws with relatively large heads, screwed into the boat where the hull meets the deck.

These two solutions create fixed attachment points on the boat. This means that the trampoline or link net must have a lot of flexibility in the position of the lacing points, or that these positions be precisely defined along the perimeter to line up with the fixed points.

4 - Aluminium beams

Regularly the front beams of cruising multi-hulls, and notably catamarans, are sections of masts with an extruded rail. In this rail, based on its type, we can place flat or cylindrical slides. Remember to be careful when choosing your slides because the inexpensive, plastic ones will not be able to withstand intensive trampoline use.

Other lacing solutions include lacing directly around the beam; however, this doesn't look nice, and quickly wears out the rope.

5 - Cables

If there is no solid lengthwise structure to rely on, we can tension a cable to fill this role. Of course, the cable will not be as rigid as a structure and so will create a dip in the trampoline, but could be the logical solution under certain circumstances.

This particularly concerns the front areas of trimarans, between the aft beams and the central hull, where there is no front beam. A cable may be tensioned there but certain precautions should be taken.


Installing net and technical fabric trampolines

Lacing or snaking

In this section, we will examine the different ways to fasten a trampoline in place with a tension rope, without taking into account the type of trampoline material.

The starting principle is that, to efficiently and successfully install the trampoline (or link net) on a boat, it must be strongly tensioned. Consequently, a tension gap must be left between the trampoline and the boat (hull, dead eyes, rail, etc.). Leave between 5 and 15 cm with the following principle: the larger the gap, the easier it is to tension the trampoline, but the greater the risk that an object (or a foot!) could slip through this gap.

Different types of lacing

Linking the trampoline (or link net) to the boat is most often accomplished by lacing or snaking, using one or several ropes. This solution presents many advantages and few disadvantages. (Remember to order your tension ropes when placing your trampoline order; 4-mm, 6-mm, 8-mm, or 10-mm polyester tension ropes are available on our web site.)

Advantages

  • Tension adjustment,
  • Security with several ropes distributed along the perimeter,
  • Adaptation to different types of lacing,
  • Simple to install.

Disadvantages

  • Installation time (it takes time to re-tension and evenly distribute the tension).
  • Regular checking of the ropes. When in doubt, several small safety ropes may be tied here and there to reinforce the lacing.

1 - In-line lacing

This type of lacing consists in passing the rope alternately through the trampoline eyelets and around the boat's dead eyes.

We use one continuous piece of rope on each of the sides of the trapeze forming the trampoline.

Tie a stopper-knot at each end of the rope to firmly maintain the tension of the rope.

Be sure to choose your rope well: sheath rope (sold by the meter, can be ordered on our web site), high resistance, low stretching, UV-resistant (multi-strand halyard).

2 - Perpendicular lacing

Perpendicular lacing is more effective than in-line lacing in terms of tension, but the boat's attachment system needs to be compatible, as is the case with slides that can be positioned directly across from each grommet, or fixed rings also placed across from the grommets.

This makes tensioning easier and more efficient because of the rope's 90-degree angle at each attachment point. This is also the best way to preserve the tension rope.

Remember to be sure that the diameter of the rope passed through the fixations twice is adapted to this use.

Furthermore, you need to block the transposition of the slides, if necessary, at both ends of the rope.

3 - Double lacing

Double-lacing is a combination of the first two types of lacing, and providing stronger tension than perpendicular lacing.

Like a block and tackle, this system makes tensioning easier and evenly distributes the tension over the different pieces of rope.

4 - Individual lacing

This is the ideal solution when the fixation points on the boat are spaced far apart. This type of lacing results in the strongest level of tension.

Each attachment point has its own independent tension, multiplying the level of safety.