Image credits: ©Facnor
As their name suggests Facnor Furling Systems are a French manufacturer with over 30 years dedicated to all forms of onboard furling systems for ocean racers and cruising sailors alike.
The Facnor Flatfurl is a structural furler. For a definition of a structural furler – see our previous blog here, together with a comparison of wire vs composite structural furling systems here.
One of the primary benefits of a structural furler, over traditional genoa reefing furlers (with aluminium foils), is that the drum is a much lower profile, which maximises sail area and keeps the foot of the jib/genoa close to the deck. Hence the name – Flatfurl – “it does what it says on the tin”!
Apart from its sleek design, the Facnor Flatfurl Drum has another key feature.
Whilst it might look like a continuous furling line drum – it is actually a single furling line system. This means the end of the line is attached to the centre of the drum and to unfurl the sail you pull on the sheet and the furling line winds onto the drum. Then to furl away, you pull on the single line and ease the sheet.
A single line on this compact drum is achieved by using a reduced diameter, single braid Vectran or Dyneema® furling line. The low-profile furling drum has a large external diameter but a very small internal diameter and, as the sail unfurls, the line builds up on itself, inside the drum. This means the force of the line located at the edges of the drum diameter provides more force for the start of the furl.
There are four sizes in the FLT Drum range for boats from approx. 20 – 40ft with forestay wire diameters from 5-10mm. There are two versions of the 5T Safe Working Load (SWL) FLT Drum: a 12,7mm pin and a 16mm pin version. Pin diameters are critical to the structural furling drum specification because of the fixed toggle attachment to the mast tang and deck chainplate.
It should be noted that whilst these drums are specified for boats with wire forestays up to 10mm, 8mm wire is normally considered the cross-over point where it is recommended to switch to a torsional composite forestay. The limiting factor is the impact of increased torsional loads on 1x19 wire and the potential for it to be damaged. However, Dyform wire, which has a much tighter construction and more resistant to the torsional forces, can be used up to 10mm.
The final important point to mention regarding structural furlers is that the bearings are specifically designed to be under constant load. The structural furler has titanium bearing races compared to aluminium in a standard code zero furler. So, whilst both the drums and swivels of structural furlers look almost identical to standard code zero furlers they are very different and a code zero furler should never be used in this specialist application.
If you have any questions about Facnor Flatfurl, please feel free to email us at [email protected], or click the link below:
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Product review: Facnor Flatfurl structural furler