Sun awning design
I am replacing my current 'boom-tent' style awning with a suspended flat awning above the boom and I am struggling for ideas to allow the awning to extend over the side decks.
The fixed support points for the new awning are from the running backstays either side of the cockpit forward to the cap shrouds (and around the sail stack at the mast end of the boom). The problem is that the boat is very beamy between these points (see picture below) and there will be no coverage of the side decks.
My thinking has gone down the path of battens and poles as a way of extending the flat awning out beyond the support points. The trouble with battens in pockets on the awning is that they will bend and it will be very difficult to get the tension needed to avoid it all flapping around. The trouble with a pole is that it will have to be suspended in mid air with the awning stretched to the ends.
I have also considered taking the two spinaker halyards down to the max beam position and using these to extend the cover out over the side deck. However this means tensioning the halyards over the rod rigging at the very top, not a good way to treat rod.
Has anyone had any experience with any of these (or other options)?
Re: Sun awning design
You can probably design it so that the awning fits in place underneath of the boom. Thus using the boom as one attachment point for supporting the athwartships poles. Ditto on attaching things to the boom at the gooseneck. And if you're so inclined, you can rig up a split bridle so that the main halyard functions to support them as well, if needed.
Also, plan on rigging various guying lines from the toerail or lifelines, to the awning's (heavily roped, & grommeted) edges, so that it's more stable in a breeze. Perhaps using snap hooks where they link to the lifelines or rail, so they're easy to disconnect in a hurry when the need arises.
One other perk of having the awning underneath of the boom is that it's easy for crew of any height to easily adjust or set it up. Which isn't necessarily the case with one rigged over top of the boom. And as well, if your awning's designed for deployment above the boom, then you'll need to detach/move your lazy jacks out of the way every time you use it. Re-rigging them prior to going sailing. Which can be a pain.
Another option is to design it so that the awning when not in use, rolls up co-axial with the boom. And gets clipped in place onto it when it's not deployed.
As to whether or not to make it a 2-piece affair in such an instance, vs. a 1-piece unit, is up to you. And some of that decision is also influenced by your desires on how much you want it to be fully imperious to rain. Which, it may be possible to build it so that the 2 "halves", are actually sections of one piece that are connected by a part of the awning that stays in place underneath of the boom all of the time. Thus avoiding drips & leaks along any panel joints in a 2 or 3-piece affair.
The one which I had that went underneath of the boom, stretched from the vang attachment point, back to the mainsheet block on the boom's aft end. Pretty much right at the aft end of the cockpit. And there was an athwartships pole in a sleeve at both ends of the awning. Which made it really, really easy to stow the thing. As all you had to do once it was disconnected, was to roll it up like a window blind.
It had a few other trick features, but hopefully the primary ideas are clear enough.
Note: It's definitely worth planning on incorporating side curtains, possibly detachable ones. Made of either Sunbrella, or mesh, to block out the low angle sun at dawn, & day's end. As well as reflected rays in the day time.
Also, if you put a self-locking, screw pin shackle on the mainsheet where it meets the traveler, then it takes but a few seconds to move the sheet fully out of the way of the awning. So that you then can build an awning which stretches from the mast or vang, all of the way to the backstay. Just figure out another way to keep the boom locked in position when the sheet's disconnected. The extra shaded deck space it provides definitely makes it worth looking into this arrangement.
Oh, & obviously you can still use the running backstays as attachment points for the awning itself, or it's poles. Ditto your shrouds.
Re: Sun awning design
Latitude 38 liked my inexpensive, easy to make (no sewing machine necessary) mobile awning. Something I could use around lazy jacks, in the cockpit and on the flush deck for lounging (around the two stays between the mast and forestay). I needed it done quickly too before going cruising for a couple of months and needed something for the cockpit as I didn't have time to get the canvas from the bimini to dodger re-done in time.
I left enough space in the hem for a pvc pole if I wanted it like you describe. However, I never found the need since it's nice to be able to provide shade tied down to the toe rail for afternoon/sunset periods. Its finish work is not high quality but I have had many compliments.
Latitude 38 - 'Lectronic Latitude
Re: Sun awning design
Before we left the States for Mexico, we made an awning that would also catch water.
Key, was Jim made a split aluminum fitting for the backstay, that clamped on it, and had sockets to accept thick walled pvc pipe ('cause it's stiffer).
The awning had 3 spreaders, all the way forward, "middle" forward of the split for the toppping lift , and then split for the boom topping lift, closing the rest of the way with velcro to the split spreader at the rear. The widest you want to go is about 10" overlap on the sides of the boat. In our case, I used old sail cloth for the pipe pockets, and reinforced the edges with flat tubular webbing like one used for jack lines.
To reef it, we each got on one side, and untied the leading edges from the shroud, and rolled it up till we got to the end of the boom, then rolled the tails up over the existing roll of pipes and fabric. This could then either be lashed down to the toe rail, or taken apart and stowed.
It was mounted high enough (had a webbing loop attached, using the main sail halyard to hoist by at the center, forward) to be able to scamper forward to check the anchor, and had bungees with hooks to the lifelines to hold the sides down, very quick to release if you wanted to get it down NOW.
In the case of the OP, he could use a pole or a pipe lashed athwartships across the runners, and that will widen considerably what he is able to cover with the awning.
Personally, because I'm lazy and not fond of re-doing things, I would build it to last, I'd use Sunbrella or Weather Max 80, and ptfe thread to sew it, and only make one. And if I were having it made, same requirement. An awning that size is expensive, why have one made only to have to replace it in 5 years?
Our present cockpit awning zips onto the aft end of our dodger, and used bungees to the radar arch to stretch it. I made the sides long, and they snap to the underneath of the awning most of the time, but if I want max width at the aft end, I unsnap them and they bungee onto little buttons screwed into the s/s tubing of the radar arch. (If we want to catch water, we attach a large funnel at the fwd edges, hose onto the funnel bottoms, and led into catchment jugs. I like to see the water i'm putting in.)
If you want to catch water with the large awning, you want to find where the low points port and stbd will be, and then, depending on how fast you want to catch water, make the requisite number of holes and cones and sew them in. (Mine were 3" diameter, down to 3/4" hose size. I sewed ties at the ends where we jammed the hoses up, and tied them tightly a bit below. Another method is to sew gutters on the top side of the awning, catch water at low spot.
Later on, we found the large awning too much hassle, and shifted to a cockpit only awning/rain catcher, which actually met our needs better. The OP may not want to do that if he wants to shade the teak on the side decks (it gets so darn hot in the tropics).
Fwiw, we never shaded the foredeck, although we made a reefing windscoop for it.
Most of the foredeck awnings we see use either a spinnaker pole or a line from the mast to the forestay, and the rest is just a tent shape. Works well for shade, but not so much for quick access forward.
Re: Sun awning design
Thanks for the tips. Unfortunately, as there is a bridgedeck between the main hatch and the cockpit, there would be insufficient headroom with an under-the-boom option. However I can see the advantages.
I think that I can make the runners to cap shrouds option work by having a system of temporarily releading the runners out to the toe rail (giving extra width at the back), combined with some fairly stiff transverse battens in between. Not perfect, but the best I can come up with at the moment.
Re: Sun awning design
OK, so I decided that the batten option would be too cumbersome to remove in strong wind. Also I would need to store the 4.5m battens somewhere (probably in the boom) when underway.
So, I have come up with a design which uses two long low modulus lines connected to the main halyard. These are hoisted almost to the top of the mast and the other ends made off on the toe rails on each side at max beam.
The awning is then tied out to these lines at the level just above the boom. this gives the extra width outside the runners and caps and provides a fixed intermediate point on each side to prevent the awning flapping around.
When its done I'll post some pics.
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