29 July 2009

DIY: towrope system for sea kayak

The club I used to paddle with required that we carry a towrope.
Before purchasing a towrope I obviously looked at what others were using.
It appeared that just about all the systems that I could find were the type that mounted on the kayak's deck and the tow ropes that attach to the body seem more popular for shorter tows (whitewater).
Here in Queensland a tow most times will be required when a fellow paddler's gear malfunctions (rudder failure), the kayaker is seasick (in heavy swell) or injured and occasionally too tired to keep up/continue to destination.
I did not like the look of the tow rope attached to the body: while jerking around the waist of the tower, in my opinion, it tires the paddler too much (and is dangerous in heavy seas).
I looked at what towing system was common with expedition paddlers in Great Britain and I often saw a towrope stashed away in a bag, secured on the deck of the kayak, usually behind the cockpit.


The commercially available (to me) towropes at the time were usually of poor quality and too bulky and there was not much thought given to those systems.
I believed that I could improve on those designs and come up with a better system myself: my first towrope system mimicked the British set up.
I found however that the deployment and retrieval of the towrope behhind my back was cumbersome to me (I am not very "bendy").
I thought that the same towrope could be attached in front of the cockpit where I could easily reach it without having to contort myself.
Soudkapp deck (c)
towrope system securely attached to the front deck of SeaBird Northsea.
The front of the bag has a little loop of Velcro® to keep the bag in place when deploying the tow line.

Velcro® that loops around a bungee cord, securing the bag
The remaining problems were:
1) quick release in case of trouble and
2) the towrope staying clear of paddling radius.
I solved the first with a different approach than the usual cam cleat and I use a quick release shackle.
tow line attachment (c)

quick release shackle attached to front deck lines

2) to maintain clearance off the towrope when deployed, the line is routed through a loop next to the cockpit and prevents the towrope interfering with my paddling (and getting tangled).


Dyneema® loop next to my cockpit

The towline bag: custom sewn heavy duty nylon (Cordura®) with reflective stripe.
The cover flap is looped around a second bungee when on deck and Velcroed down to itself to keep it secure.I used a towline that would float, be strong but still compact: 2mm Ø Dyneema® is the perfect line. At a braking strength of more than 650 Kg I think there is more than sufficient strength (I have used lighter lines too and they seem to work as well).
I packs down way smaller than the typical polyester water-skiing tow-rope and it's easier for tying knots around the karabiners.


15 meters of 2mm Dyneema® core lineThe towing karabiner is a stainless steel one that has a little float attached to keep it from sinking if dropped in the water.

karabiner with float. Tow line is chained for easy deployment without entanglement.
I find nothing worse than passing the clip-on karabiner to somebody to see it drop and then have to pull-in all the line again to pick it up.
The Dyneema® line is bright orange for visibility.
The anchor point is not my deck’s bungee since I have seen some fail but my perimeter line deck fitting (in front of the cockpit).
The quick release shackle has a little toggle for emergency release, in case the towed kayak is putting myself in danger I can quickly just pull the toggle to release the line, even under load.


safety quick release in yellow
The towline has been tested in many towing situations and so far has worked great.
A couple of highly qualified sea kayak instructors have endorsed the system and asked me if I could manufacture the system for them.
For a commercially available product the closest one is the towrope from Valley (just a bit thicker line without the quick release shackle).

Needless to say that a rudderless boat works so much better for towing since there is no danger of the line catching on the rudder behind you.
I know that are countless arguments and counterarguments for towlines that are attached to the kayak versus the ones to the body.
This system of mine is working great for my paddling environment (quick rescues from turbulent waters around cliffs don’t apply) but I would not mind hearing from my readers if they see faults in this design.


edited DEC2011

7 comments:

  1. Nice new take on an old concept. I wear a tow belt on the waist and it does not bother me at all. Towing is hard but the location of the towline around the waist does not make it any harder.

    Concerns:
    1. Line is too thin. If grabbed by an ungloved hand and suddenly pulled, skin will be cut and hard to hold on to.
    2. Attachment on one side will probably capsize the tower if the towed boat is on the opposite side and pulling sideways.
    3. Attachment point seems to be too weak. Rough conditions can generate a lot of force. I see the whole recessed fitting flying out into the soup.
    4. The loop to the side of the cockpit is a prime location for a finger to go into if you suddenly capsize. With enough energy to the capsizing force, you may loose the finger or two.

    ReplyDelete
  2. Haris, towing from the waist can be a pain (literally).
    1) I see your point but towing for me is not a “quick rescue from a sticky spot but more a long haul scenario. For a quick tow I should have a short tow rope.
    2) I have not found that to be the case as long as the towline is through the Dyneema loop at my hips level (acting as a fairlead)
    3) Admittedly some perimeter lines anchor points are rather weak in some kayaks. Mine are very solid and have a large washer under the deck. Ripping that out is no different than ripping out a cam cleat mounted somewhere else on the deck.
    4) How is that different than a perimeter line.. . you mean the kayak pivoting and spinning while my finger remains stationary inside the loop? I guess it’s possible but not probable.
    Much more discussion on this system has occurred on Forums.
    I have been convinced to consider a fairlead behind me but I will like to maintain the tow bag in front of me.
    Will update this post when the system is amended and tested.

    ReplyDelete
  3. I recently came accross your blog and have been reading along. I thought I would leave my first comment. I dont know what to say except that I have enjoyed reading. Nice blog. I will keep visiting this blog very often.


    Susan

    http://3128proxy.com

    ReplyDelete
  4. It's been a few years since your initial post.. has your system evolved at all?
    I'm just about to install some tow attachment points to my kayak..
    cheers, Bernie

    ReplyDelete
  5. Bernie, I don't do a lot of towing (read: none) to test shortcomings on the existing set up. Also I have not seen a system that I like better. There are commercially available system that use a thicker line (I see some merit there) but are very bulky. I hate cumbersome items and deck clutter. I also try to minimize the time I need to prep my kayak before launch therefore I have a tow rope always attached on deck on each of my kayaks (7 and counting)
    So, as they say: if it ain't broken don't fix it :-)
    The only thing I have changed it the karabiner that is at the end of the tow rope; now I use a stainless steel one that has a keylock to prevent snagging on ropes: http://gnarlydognews.blogspot.com/2011/02/gear-carabiners-for-sea-kayaking.html

    ReplyDelete
  6. why is your rope so thin? is it capable of holding something heavy and is it durable.

    ReplyDelete
    Replies
    1. I like your style of self promotion "dyneema rope" ;-)
      Anyway, I like things small to compensate for my size. My towing has never involved "swift-water-rescue-person-in-water" style; I don't use my line for a swimmer that needs to clutch it in his/her hands. If I have to tow is usually a few kilometres where a thick line will create more drag when in the water. I also like things compact and accessible therefore my 15 meters of tow-line can be easily stored in that little pouch permanently attached on deck; always there, not forgotten somewhere below deck or worse, left at home.
      As for strength, probably even too strong at a rating of almost 700Kg.

      Delete

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