Thursday, July 26, 2012

Fitting a Flat Earth sail to a Necky Chatham 16 Polymer kayak.

The Necky Chatham 16 is a manoeuvrable kayak that should suit a Flat Earth Kayak sail very well.
Unlike the P&H Delphin, which has a rigid foredeck, the Chatham deck is soft and would not be stiff enough to support a mast foot without some modification. The stiffest area was between the compass recess and a central deck elastic fitting. This was also in line with the deck line fittings, which saved drilling extra holes for the side stays. To make the stays easily adjustable I used Clamcleat white CL266W/R Mini Line-Lok cleats.

To stiffen the deck, I cut a piece of 3" thick black closed mini cell foam and pushed it into place so that it was under moderate compression.

The black sheet and the red uphaul were led aft to a pair of Clamcleat CL 213 and CL214 low profile line cleats. note how the red uphaul is threaded behind the rear deck elastic then forward...

...where it is tied off to the loop formed where the yellow back stay goes through the snap shackle. To lower the sail if there is a strong wind from behind (on a run), uncleat the red uphaul, then pull on the end. This pulls the back stay towards you collapsing the mast. If you rig the Karitek way (with two rear set stays and no back stay) you can't do this and in a strong wind you need to turn the bow of the kayak from down wind round into the wind to drop the sail.


  1. Douglas, I use the "two stays-no backstay" configuration. After a few years of sailing in anything up to 30 knots I still have not found the need to suddenly drop the sail and not being able to. In the configuration that I use if I release the uphaul, the sail will stay up only if the wind is dead centre coming from the stern. I don't even have to bring the kayak around 20 degrees (easily done when sailing downwind) and my sail falls down.
    I understand that your mileage might vary.

  2. Greetings Gnarly, it is good to hear from you.

    We do quite a bit of upwind sailing but like to keep the bit of elastic in the uphaul to protect the deck in case of a trashing. With two rear set stays and no backstay, if you go upwind the mast rakes back in the gusts as the uphaul (fore stay) elastic stretches and as it does so the stays slacken and the mast leans to leeward spilling wind. With two sidestays and a backstay, as the gust hits, the mast rakes back but the stays stay tight so the mast does not drop off to leeward. This dramatically increases upwind performance. We have done extensive testing using Quests rigged both ways. Regardless of which one of us is paddling, the side stay back, stay rig wins upwind every time by a BIG margin, especially in winds above force 4 (as measured locally with a handheld anemometer).

    With regard to dropping the sail, my mounting instructions are to help kayak sailing beginners. Like you I have never had any bother as I can't recall ever having to drop the sail in conditions I am happy to paddle in *. However, several beginners I am in touch with have reported epics trying to get the sail down on a run down in moderate winds.

    *In fact in testing conditions the sail seems to make the kayak easier to handle, like a big air skeg!

  3. I use the two side stays and the rear stay. With the current mounting setup, I recently had an issue in 20-25knots where the mast would not collapse when the wind was coming from behind.

    Fortunately, by releasing the sheet completely and pushing on the back stay with the paddle, the sail collapsed.

    My side stays and back stay are setup drum tight and with the wind from directly behind there was enough pressure to keep everything nice and tight and in place. I now tie the uphaul to the back stay like Douglas so a simple tug will collapse the sail back when required.

    Douglas, get rid of the Line-Loks. Use a 3turn taut-line hitch. My sails move around a couple of boats, and having the stays easily adjustable, yet locked in place when setup and sailing, a must. This hitch works great,and is easy to adjust - just release the mast slide the knot a bit, tension the mast, and check - and holds even in good blows - no issues up to 25knots so far.

    1. Hi Shawn, thanks for the tip about the 3 turn taut line hitch, I will give that a try. I had experimented with the truckers hitch but it was a bit fiddly to get the stays twang tight. :o)

  4. Hi! Does the frequency of updates of your domain depend on something or you work on blog articles when you have an inspiration or write entries in case you have sufficient time on it? Waiting forward to hear your answer.

    1. Hi Brandon, this is a sea kayaking blog so posts depend on whether I have been out sea kayaking or not. Unfortunately, I have not been out much over the last two months or so...partly due to bad weather, but mainly due to some orthopaedic problems I have been having with my knees. Good luck with your blog.

  5. Hi Douglas,

    You say: "To stiffen the deck, I cut a piece of 3" thick black closed mini cell foam and pushed it into place so that it was under moderate compression. "

    I am thinking of strenghthening the deck of my mirage 530. Is your way better than fibreglass? Did you use glue between the foam and the kayak deck?


    1. Hi Terry, sorry I missed your comment until now. I used a block of mini cell foam because the kayak was made of relatively soft PE and only used as a day boat. I think on a GRP kayak like the Mirage some GRP strengthening with glass and resin would be best. I also like to mount near deck mouldings such as a compass recess as the deck is stiffer there than on a flatter area.