Lagoon 450S Furling Gennaker System
by Bryn Wellington


The restrictions of 2020 whilst frustrating our cruising plans, did provide a great opportunity for us to fit out our Lagoon 450S for extended cruising.

High on our wish list we had an additional off the wind sail. We’d had an asymmetric spinnaker in sock on one of our previous cats, but from time to time it was a handful when dowsing if a building breeze got the jump on us – I’d had a few experiences where even with the sock down over the chute it still had enough power to try and throw me off the front of the boat – ha! So this time we decided we’d opt for a gennaker as our next sail (still might get a spinnaker someday too :-))

We’ve had the gennaker on for about 9 months now, travelling over 3000nm. It’s seen a lot of use with good coverage of sailing angles and breeze, and practically no incidents along the way.

It was a great DIY project, or could be professionally fitted. In this article I’ll run through a list of the equipment required and give any pointers and tips that I’ve come across during the install and use.

The Sail – we opted for a North G-Zero. It’s beautiful! Lightweight laminate with a great shape and a bit over 100 sqm in size. It sails surprisingly deep (160 true), and can handle up to 15knts apparent wind speed (ie up to around 20knts true when sailing down wind at all). And it’s a terrific motor – due to its size – generally giving us a couple of knots more boat speed than with our geni. It so easily does 7 in 11 (7knts in 11 knts TWS) and up around 10knts in 16 knts or so.

The sprit – is a 100mm (4”) diam x 1.2m (4’) long Forespar® sprit with removeable bayonet inboard end fitting. This is a great, robust sprit with integrated outer tang ring, and we utilise the bayonet fitting to quickly remove the sprit when in confined marina spaces, or if anchoring or picking up a mooring in places with strong current against wind where the boat can override our bridle and cause it to chafe on the sprit’s baby stays. The baby stays are 8mm (5/16”) 1x19 stainless wire (Dyneema® would do the job, but that’s the beauty of a cruiser – a few grams here or there aren’t going to hurt us and they’ll last for ever). The stays have Ronstan RF1507M0808 Swage Toggles at each end to ensure good alignment of loads and connect to RF2429-10 padeyes down on the hulls (with big st/st backing plates on the insides). The top ends of the baby stays also have RF6300 fixed eye snap shackles on the toggle ends to allow easy quick removal and clipping to the pulpit each side when not in use.

The Furling System – we have an Ronstan RS216000 Series 160 Continuous Line Furler (standard bottom up furling format) with matching RS216010 top swivel. Connections for the furler hardware are super simple and trouble free. An RS216020 snap shackle adapter on the underside of the furler allows quick attachment and removal from the sprit tang, and an RS216050 HR shackle at the halyard completes the other end (a snapshackle could be used here too for tool free attachment) and an RS216015 neoprene cover for the swivel. The torsion line luff is tensioned 1:1 at top and bottom, my existing spinnaker halyard clutch with a max holding power of 1000kg was adequate for the tension on the luff – for required sail shape and furling. The torsion line is 12mm with Ronstan RS216040 alloy thimbles. My continuous furling line is relatively short – I don’t run it back to the helm or cockpit, rather I furl from up on the foredeck, where I get a good view of how the furl is going (to ensure a nice tight furl that cant bubble out), and so that it is very easy to remove the furling line when required (when running it back, you generally will need to remove all the lead blocks, cleats etc). The 10mm furling line has a Ronstan RF47109 42mm Soft Attachment Snatch Block on it with a doubled up 8mm shock cord tensioner running via an RF6100 snapshackle to a Dyneema® loop on a nearby staunchion base. It is amazing how small the furler looks compared to the sail, yet with co-ordinated easing of the sheet and sailing deep down wind, how easily and quickly the furling is completed.

The Halyard System - I was lucky with the halyard setup – my boat already had a 7/8 positioned deflector block, mast head halyard sheave, clutch and winch for a spinnaker. I used a 12mm Dyneema® halyard with a parrel bead just above the eye splice – thanks to my old Ronstan mate Pete who spliced her for me and added an RF1315 rope stopper ball – to avoid accidentally grinding the shackle into the deflector block. At the mast base I have a Ronstan RF104100 Series 100 Core Block™; perfect for the high static load.

The Sheeting System – we are running Robline ORION 300 14mm double braid sheets, just bowlined to the clew, led back to a RF104100 Series 100 Core Block™ at each aft corner (I used standard universal shackle head models as there were already folding padeyes in place on my boat, otherwise the RF104140 Stand-up models would do perfectly). The blocks are tied up through their hollow hub with shock cord to ensure they are aligned and don’t drop down when unloaded. From there the sheets run to my beautiful, shiny Andersen Full Stainless 62ST two speed (manual) winches on the sides of my cockpit (a bit of a contrast to a racing setup as when I’m winching, I’m standing on either the day bed or saloon table seating! :-)). Tip - when the zero is furled I run the sheets around the front of each pulpit – this pull by each sheet from opposing directions seems to resist accidental unfurling.

The Marriage Savers – now this is my top tip and professional secret! Our marriage savers are Bluetooth wireless headsets (as used on motorbikes). With generally only my wife Kerry and I sailing, they are invaluable for things like gennaker furling, anchoring, docking etc etc. They eliminate the yelling and confusion and give some semblance of knowing what we are doing – particularly in the case of our furling the zero where the boat is sailed on auto pilot deep downwind to relieve pressure, I’m up on the foredeck furling, and Kerry is out of sight back down in the cockpit easing sheet.

Well, that’s the setup – there are a bunch of pics of the system and hardware to help make things clearer, or give your local Ronstan reseller or office a call if you have any questions.

There’s even a video of the system if you don’t like reading. It’s take 2 of the vid, as just as I was finishing the first attempt, I looked up from my phone/camera to see a cloud of splume just in front of us and had to dash back across the tramp to the helm, helm down and had a full grown hump back whale just slide on down our port side! There might even be a bit of a blooper of the moment at the end of the vid :-)