Re: New sails [cross-cut * Nautosphere VOYAGER v tri-radial HydraNet]
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Your cruising grounds sound splendid, enjoy! I wanted to add a bit more about why I decided to go with crosscut Hydranet instead of going with the Tri-radial. First I want to agree with Bill Kinney that from design standpoint the Tri-radial construction makes sense because the fibers are better aligned with the loads. Bill also makes the point about there being more seams with the Tri-radial but actually it seems to me that there are a LOT more seams and many of them run in a near vertical orientation whereas with the crosscut the seams are mostly fore and aft. Each seam represents a thicker/stiffer area in the sail which increases the furled diameter and is going to somewhat increase the force required to furl and unfurl a main or mizzen. Also near vertical seams won't slide as easily across the plastic lip of the mast extrusion opening as fore/aft seams. I personally like the fact that with my new furled main and mizzen that I can easily slide a finger in between the sail and the mast cavity. With my old Dacron sails there was even more room. I have heard it said many times on this board that one of the great things that Amel did when they designed the furling systems on our boats was to provide a nice large mast cavity which essentially eliminates jams when furling. I can say that with my original Dacron cross cut main and mizzen that even with some furling mistakes that we have never had a jam and I attribute that to the small furled diameter of the original crosscut sails and the large amount of room remaining in the mast cavity. So the Tri- radial design makes perfect sense to me, battens can add area, sail shape and performance but with just the two of us making long passages, the reliability of the furling is of more importance to us. So this is the reason we are staying with the original Amel sail design though I understand that it won't be for everyone. Best of luck in making the best decision for you.
From: David Vogel <david.vogel@...>
Sent: Tue, Jan 18, 2022 4:59 am
Subject: Re: [AmelYachtOwners] New sails [cross-cut * Nautosphere VOYAGER v tri-radial HydraNet]
Thanks to you all for your answers and additional inputs – all very good info.
We’re still considering our options, and will do some cruising up and down the East coast of the NZ North Islands while we deliberate.
On 7/12/21, 3:58 pm, "David Vogel" <main@AmelYachtOwners.groups.io on behalf of david.vogel@...> wrote:
After 5 years and ~25,000nm, our sails are starting to show their age, and so we are now scoping replacements. Mainly UV-damage to the leech area of the main and mizzen, the main- and mizzen-sails that were on the boat at purchase had no UV-protection. Which (we have discovered) is an oversight that we should have recognised and had corrected early on, especially once we started sailing full-time in the tropics (where we have now been continuously for >4 years). Being tri-radial cut, it is not so easy to re-cut the sail/s to eliminate the compromised fabric, which is a shame because, apart from the outer 30cm, the remaining fabric is still sound.
We will be continuing to cruise in the tropics for the foreseeable future. Meaning, that laminates are out of consideration.
Explanation: we have seen too many cruisers (and heard even more stories) of those paying for expensive state-of-the-art so-called "cruising laminates", only to have them start to de-laminate after only a season or two. The cause, seen more often in the tropics, seems to be that the laminating manufacturing process used to sandwich the various fabrics together, uses heat to melt and/or cure the glue, and the temperatures used are deliberately kept low in order to protect the fabric from thermal damage during manufacture, being only slightly higher than 100ºC. The in-mast temperatures reached when sails are furled, especially in the tropics, approaches or exceeds this temperature. The situation is, reportedly, worse with in-mast furling systems (as opposed to slab-reefing). This is as explained by several long-term cruising sailors with vastly more experience than us. It makes sense, and aligns with what we have seen over the past few years. Conclusion: no laminates for us.
Which leaves us with more conventional dacron-based woven sail-cloth, including hybrids that utilise high-modulus fibers such as "Ultra-PE" (Ultra-Polyethylene, such as Spectra or Dyneema yarns), which is introduced in order to improve strength and shape stability - once such sailcloth being HydraNet. I have heard that HydraNet starts to lose it's dimensional stability after a few years (maybe as short as 3-4 years), firstly becoming soft to handle, and then baggy. Which creates problems firstly for sail performance, and then also for in-mast furling systems. Which leads me to ...
Does anyone have experience with Hydranet sails beyond 5-7 years? The use-case here being full-time live-aboard cruising, meaning, permanently rigged (not removed for the off season, nor on-anchor, as we have to ready to sail-away at a moments notice; and we generally avoid marinas, so the sails are on 365 days a year); mileage: 3,000 to 5,000nm a year, all-weather blue-water passage-making in the topical (hotter) and mid-latitudes (greater likelihood of encountering stronger than gale-force).
Next, the cut of the sail ::: traditional best practice within the AMEL community is to use a TRI-RADIAL cut - in addition to aligning the high-modulus fibres to the load (mainly vertically, roughly parallel to the leech, radiating from the head, tack and clew), this allows the use of differing weight fabric around the sail - heavier at the foot and leech where there are greater loads for fully-unfurled conditions, and needing to bear a greater load in stronger wind-condition when the sail is partially furled; and lighter sailcloth in the luff areas, less loading under fully unfurled conditions, and less likely to be exposed to high winds (because it should furled away) that would permanently deform a lighter fabric. But not easy to re-cut. Meaning that once a sail is 'blown' and starts to deform, or suffers UV-degradation along the leech, it largely becomes a throw-away item. (Proper UV protection in the first place would avoid this, either the paint-on solutions or extra covering such as an extra layer of sailcloth, or Sunbrella or, perhaps preferentially, the lighter WeatherMax.) But the outcome is the same, once UV damaged such that the strength of the outer sailcloth is degraded, even if the rest of the sail-cloth is sound, there is not much that can be done.
So, I have now questions about useful life of Tri-Radial HydraNet sails - especially if/as it starts to age, and becomes soft &/or baggy, thereby potentially introducing problems with our in-mast furlers. As a consequence of which I am now starting to look at other contemporary alternatives.
Sail construction --> CROSS-CUT. Normally, due to the conventional 'best practice' within the AMEL community, I would not consider this. But there are advantages, it would seem, with cross-cut sails with respect to the 'furl-ability' of the sail. Specifically, because the nearly horizontal seams spiral up the mast as the sail is furled, and hence do not overlap during furling (as is the case for a tri-radial cut sail), cross-cut sails can accommodate a heavier cloth within a given mast profile. However, cross-cut sails do not have the advantage of being able to use heavier cloth in areas of greater load, as is the case for tri-radials - each cross-cut fore-to-aft panel uses the same-weight sail-cloth. Offset against the use of a heavier cloth across all the sail.
Type of fabric: "Nautosphere VOYAGER" is a fabric we have just heard of. It is a hybrid fabric (that is, dacron base incorporating high-modulus yarn, in this case, dyneema). Downside, it is not suitable for tri-radial construction - only for cross-cut. It's claim to fame is that the dyneema threads are woven across the bolt of fabric (that is, along the weft), meaning that the strength and dimensional stability of a cross-cut sail built using this fabric will be roughly vertical - that is, approximately parallel to the leech, which is in alignment with the primary load lines. A cross-cut sail made of this fabric can be made of heavier cloth (due to the better furl-ability), meaning greater strength initially and, all other things being equal, greater longevity. And, being a simple cross-cut, simpler construction with a lesser number of panels (and seams, than tri-radial), meaning reduced labour cost. In addition, UV damage at the leech can be more easily re-cut out. Which leads me to ...
Does anyone have experience in cross-cut sails for the main &/or mizzen for the in-mast furling AMELs, and especially the Super Maramu.
Does anyone have experience with, or knowledge of, "Nautosphere VOYAGER" fabric?
Thank you, in anticipation, for your shared insights and knowledge.
On-the-hard, Riverside Drive Marina
Whangarei, New Zealand