How to Install a Dyneema Trampoline on a Catamaran
Most production catamarans come with polyester trampoline netting. It does the job until it doesn’t — UV degradation, stretch, and a surface that gets progressively less pleasant to walk on in rough conditions. Anna twisted her ankle badly on the old polyester nets. That was enough.
The replacement is Dynex SK78 — the same family of material as high-performance halyards and sheets. It’s Dyneema under a different trade name, and the reasons for choosing it over polyester are straightforward. The UV stability is inherently better, and the black colouring has a waxy protective dye that adds further protection. The stretch is minimal once the weave settles in. The strength-to-weight ratio is in a different class. The initial cost is higher; over the life of the net it works out cheaper.
The installation method matters as much as the material. Most trampolines use a continuous lacing around the perimeter — one long line that winds through the net and around the frame. The problem is both structural and practical. Structurally, if that lacing chafes through anywhere, the whole thing can unravel from that point. Practically, you cannot get meaningful tension into a net with continuous lacing — the friction through all those turns means you’re pulling hard at one end and barely loading the other.
Separate lashings fix both problems. Each individual lashing line ties independently to the stainless rod that runs through PVC tubes bonded into the hull — so if one fails, you lose one connection point and nothing else. And because each lashing is independent, you can apply serious tension to each one individually and dial in exactly where the net sits. The result is a trampoline that feels close to walking on a solid surface. Shayne uses a two-thumb-knot cinching configuration rather than splices — the knot ends up hidden inside the lashing, the appearance is clean, and it saves days of fiddly two-millimetre splicing with no functional advantage.
The weave on knotless netting is loose when new, so the net stretches considerably in the first few sessions as the weave loads up and tightens. Plan for three to four re-tensioning sessions before it stabilises. After that, once a year is typical.
Materials:
- Dynex/Dyneema knotless netting — Netsystems (net-sys.com)
- 6mm Dynex/Dyneema edging rope
- 2.5mm SK78 lashing lines cut to 900mm lengths
- 4mm 316 stainless steel rods
Two-Year Update
Two years, two oceans, and a Caribbean summer later — the net looks and performs almost exactly as it did when it went on. The UV degradation that had destroyed the previous polyester nets in under two years hasn’t materialised. A few of the temporary knots that should have been finished properly need tightening. That’s the maintenance report.
This post is part of the complete Paikea front end rebuild series — carbon beam, longeron, seagull striker, martingale, bow pole, and trampoline, all built from recycled America’s Cup mast sections. The full build detail is in the members’ technical library. Join here.