Flat Earth Sail

Places, technique, kayaks, safety, the sea...
User avatar
gnarlydog
Posts: 234
Joined: Fri Jul 03, 2009 5:35 am
Contact:

Re: Flat Earth Sail

Post by gnarlydog »

a slightly different take on rigging the Flat Earth Sails:

Image
mast base_sleeved_c by gnarlydog, on Flickr

more details on carbon masts at: http://gnarlydognews.blogspot.com.au/20 ... pdate.html

User avatar
Douglas Wilcox
Posts: 3639
Joined: Sun May 11, 2003 1:31 pm
Location: Glasgow
Has thanked: 5 times
Been thanked: 50 times
Contact:

Re: Flat Earth Sail

Post by Douglas Wilcox »

Hi Mal, those are exactly the sort of conditions that a line running round the back stay and back to the cockpit helps to get the sail down when running before a strong wind. I. Use the free end of my up haul line as in this photo...

Image

From your description it sounds like your sails were in the water. I think it most likely that the masts bent then, with the movement of the kayaks in the waves acting against the weight of water in the sails.

Some sail handling practice in more moderate conditions should pay off. With regard to carbon fibre masts, when they go they make a real mess. I broke three carbon fibre windsurfing masts when windsurfing and in each case the sail was trashed by the sharp ragged ends.

I am glad you have not been put off. In stronger winds I tend to keep away from sea lochs, lochs and lakes. The wind is always far too gusty, the steadier wind out at sea is preferable.

Douglas

ruralweb
Posts: 647
Joined: Wed Oct 19, 2011 5:14 pm
Been thanked: 1 time

Re: Flat Earth Sail

Post by ruralweb »

Hi Douglas
I've been playing with trying the uphall to the rear mast stay as you describe but forgot to yesterday!

My mast never went in the water so the bend was purely due to the wind gust - my mates sail did go in the water which is why I suspect his bend is worse than mine.

They masts are amazingly strong TBH - many times I've been out and checked for a bent mast but this is the first time in many many hours of sailing. Nothing actually failed and the sail can still be used so its pretty amazing build quality.
Mal

Scots_Charles_River
Posts: 830
Joined: Sun Feb 24, 2008 6:10 pm

Re: Flat Earth Sail

Post by Scots_Charles_River »

Nice thing about the Bicpsort Sails is they de-power at 18knts, due to the flexible outside poles.

ruralweb
Posts: 647
Joined: Wed Oct 19, 2011 5:14 pm
Been thanked: 1 time

Re: Flat Earth Sail

Post by ruralweb »

de-power at 18knts
we were shooting along in about 35 mph winds and the sails were great so 18 knts is a bit low - you can depower flat earth sails by changing the rigging but we were just caught out by some big gusts which we didn't have time to do much about as we were trying to stay upright!!
Mal

User avatar
PhilAyr
Posts: 414
Joined: Mon Oct 18, 2010 12:51 pm
Been thanked: 6 times

Re: Flat Earth Sail

Post by PhilAyr »

Scots_Charles_River wrote:Nice thing about the Bicpsort Sails is they de-power at 18knts, due to the flexible outside poles.
Have you tested one ? From what I have heard they are difficult to control and only work in a following wind. You could be better off with an umbrella.

Phil

Scots_Charles_River
Posts: 830
Joined: Sun Feb 24, 2008 6:10 pm

Re: Flat Earth Sail

Post by Scots_Charles_River »

Nope, just got one yesterday. They are 'hands free' for depowering in a gust. I don't have the paddling skills to adjust a sheet or halyard and paddle. There are also a lot cheaper if you want to dabble in sailing a canoe/kayak.

I saw Patrick Winterton talk through a video clip of him capsizing, then de-rigging a sail, then rolling backup ! Cool.....

User avatar
PhilAyr
Posts: 414
Joined: Mon Oct 18, 2010 12:51 pm
Been thanked: 6 times

Re: Flat Earth Sail

Post by PhilAyr »

Ruralweb wrote :
My mast never went in the water so the bend was purely due to the wind gust - my mates sail did go in the water which is why I suspect his bend is worse than mine.
Now that does surprise me ! I would have thought that the rig mounts or deck would have given up before that. This sailing business never ceases to amaze me ! :-)

Phil

ruralweb
Posts: 647
Joined: Wed Oct 19, 2011 5:14 pm
Been thanked: 1 time

Re: Flat Earth Sail

Post by ruralweb »

I've a plastic kayak so that would explain the deck not giving way and the rigging lines must be rated for 100kg at least so all the force of the sail would be concentrated just above the point where the rigging joins the mast. Pressure would have been released when my kayak tilted on its side but who knows what the pressure on the mast at that point is?
Mal

ruralweb
Posts: 647
Joined: Wed Oct 19, 2011 5:14 pm
Been thanked: 1 time

Re: Flat Earth Sail

Post by ruralweb »

Geoff at Karitek has been chatting to my mate about his mast and said that the mast is designed to bend at above 25mph wind speeds to protect the sail from damage which sounds reasonable. He has however sent him a new mast!

I have bent mine back into shape and was out at the weekend sailing with no problems at all.
Mal

mick m
Posts: 445
Joined: Sun Sep 06, 2009 1:23 am
Location: East Gippsland Vic Australia
Contact:

Re: Flat Earth Sail

Post by mick m »

Good morning,
Thers a lot of veriabels in this sailing game, finding the right comprimises for sea kayaks is the name of the game, over the last nine years Iv desided thers no absalutes when fiting the sails and still paddlers are finding diferant aproches to fiting sails
A few things about what I try and incorporate into my designs,
Ther needs to be a fuse in the system, to this end I youse three diferant aproches, I have a loop of shock cord in the up hall to take the loading out of the mast when it hits the water, the stays are strong, but not to strong and I wold hope that thay wold brake befor the kayak brakes, and the mast is the other designd week point, in a desasteros prang I wold much prefer to bend or eaven brake the mast than punch a hole in the deck of my kayak.
I have shied away from carbon for this main reason, and as Duglas has mentiond when carbon fails it tends to splinter or shater sharp shards soon make a mess of sails. Sume paddlers, like Gnarly dog have had good resolts with carbon.
Deck flex is sumthing to consider, thers a lot of downword preshure on a stayed mast douglas has mentiond a bit on this on his blog and about yousing a pillar under the foot of the mast which I think has good merats.
Best regards

Mick MacRobb
flat earth kayak sails

ruralweb
Posts: 647
Joined: Wed Oct 19, 2011 5:14 pm
Been thanked: 1 time

Re: Flat Earth Sail

Post by ruralweb »

the mast is the other designd week point, in a desasteros prang I wold much prefer to bend or eaven brake the mast than punch a hole in the deck of my kayak.
Agreed - there has to be a weak point in any system although my sail has had a real bashing over the last 6 months and has not suffered any lasting damage. I would much rather the mast bend/break than the sail rip which is the expensive bit.

Just fitted navigation lights to the top as we were out late at the weekend and even with a head mounted nav light boats were not seeing us because the light was being masked by the sail from the front.
Mal

User avatar
Kayaks'N'Beer
Posts: 802
Joined: Wed Aug 17, 2005 7:12 pm

Re: Flat Earth Sail

Post by Kayaks'N'Beer »

ruralweb wrote:Geoff at Karitek has been chatting to my mate about his mast and said that the mast is designed to bend at above 25mph wind speeds to protect the sail from damage which sounds reasonable. He has however sent him a new mast!

I have bent mine back into shape and was out at the weekend sailing with no problems at all.
I'm so glad I didn't take my dads out for a try just before new year there. 40kts gusting up Loch Lomond I thought it would be ideal to try out the sail but I ended up going with the devil I knew. Old man would have killed me if I'd trashed his sail, he hasn't even had a shot of it yet.

kiwikayaker
Posts: 1
Joined: Sun Sep 29, 2013 8:05 pm

Re: Flat Earth Sail

Post by kiwikayaker »

I've been loving my flat earth sail. Also read gnarlydogs mast to deck reinforcing mod, but I hastly mounted my sail rig to my epic 18x without reinforcing, and for a month I noticed my kayak foredeck (which has a nice camber shape but a lightweight layup) was slightly deforming when under load from sudden wind guts, when I was caught off guard and unable to spill the sail or increase my paddle stroke to release pressure! Yesterday whilst two kayaks were hanging onto my sail rig and getting a free ride a sudden wind gust (35 mph on a long lake with pletny of fetch) blew my sail over and cracked my boat!! So Ill be doing some below and above foredeck glass/carbon reinforcing work before my next sail deployment!!
not sure how to add a pic here but I took a snapshot of it

Post Reply