• 16th October 2007 - By adventuresofgreg

    Well, I have finally decided how I am going to gain my stability for moving about WiTHiN.

    Here is a quick a review of the problem:

    I decided after the roll over test, that stability in the prototype boat WiTHiN is just fine when I am seating in the cockpit. However, I do require additional stability for standing up through the top hatch, climbing in and out through the top hatch, and crawling on deck. We took a look at a number of options in the blog post. I decided to go with a ballast in a bulb on the end of a keel.

    I calculated that I could take all of my internal ballast and add that to the keel as well, and calculated about 100 pounds, 4.5′ below the bottom of the hull. I even went as far as drawing up plans for a stainless steel keel frame. Then when I was at the gym the other day, I picked up a 100 pound dumbbell to do my 20 single arm bicep curls with (ya, right!), and realized that there would be no way to properly secure this 100 pounds with a very long moment arm to my thin kayak hull!!!

    After more thinking it just seemed dumb to have to lug around an extra 100 pound of weight just for the occasional time when I need to stand up. Especially for this prototype boat. I am trying to get WiTHiN ready for a mini-expedition in the Gulf Islands where I will spent a few days peddling and living aboard her to learn more about what it will be like to live in WiTHiN. I’ll need to load and unload her by myself, and lugging this deep, heavy keel around is going to be a major pain.

    So, I looked again at my retractable outrigger options and between me, Rick Willoughby and Richard Roake, we came up with the retractable slider-riggers.

    These will be two outrigger arm that will slide in shell tubes that will be glassed right into the cockpit approximately behind my seat back. Each arm will be angled at about 30 degrees. When the floats are retracted, they rest against the sides of WiTHiN and will be molded to fit as if they were two short wings. When retracted, then should not cause much additional aero drag (head winds, not speed), and shouldn’t effect WiTHiN’s ability to right herself after a capsize. They should help stabilize her during sharp turns, as one of the buoyant ‘wings’ would dip into the water when she leans over during a turn.

    When extended, they should provide enough buoyancy to allow me to stand up, climb in, out or walk on deck. They are not very hydrodynamic in the extended position in the water, but they are not meant for use while underway – at least not this prototype version of the outriggers.

    I will be able to deploy the outriggers from inside WiTHiN by using handles through slots cut in the slider tubes behind my seat. If she were to capsize with the floats extended, I would be able to easily retract them from my upside down position inside the cockpit.

    Here is how I am making them:

    I modelled the outrigger shapes in my 3D application, then sliced each of up into 1″ layers. I printed these flat slices out and tiled them together to create actual size patterns. I traced the patterns onto 1″ thick Styrofoam and cut each slice out with an Exacto knife.

    The 1″ thick slices are stacked to form a stair-stepped float, glued together, then sanded smooth. The I will cover with glass and insert and glass in my aluminum outrigger arm tube.

  • No Responses to “stability solution floats”

    • Anonymous on October 17, 2007

      I would have two arms that are parallel that go from a forward position –closed to open back and out to lock
      I still think a hachback lid to get out the back is better.

    • Anonymous on October 17, 2007

      Hi Greg,

      Me again,

      Nice ideas – but: These tubes holding the outriggers, would't be rather fragile. Also, there wil be twisting moments of the waves? Tubes for extension of the outrigers, glassed inside right behind your back – I thought that you are going, somehow, transfer your self to the back of the boat for rest & sleep?

      Me again: What's wrong with permanent light and thin – hawaiian outrigger?

      Check this one:

      outrigger on scull


      Keep it up!
      Almost there!

      Martin Pernicka,
      Montreal, QC

    • Anonymous on October 17, 2007

      Hi Greg,

      I was watching your stability test and float solution and as Martin said, i got a little worried.

      First is that even thow your friends told you that was hard to keep the kayak upside down, heavy weader in the sea will not make that much effort to do it.

      I think that the worse senario would be heavy wind with big waves turning you around like a little ball. That is possible and i have seen that happening with a brazilian guy who crossed the atlantic ocean rowing.

      The other thing is the strenght of the stability arms. In heavy weather they wont hold too long. besides, what happens if the two arms break? How will you get into the kayak?

      My sugestion is the same as Martin's: Acess from the back of the hull! Fasten some handles in the back of the hull so you can have a way to climb from the back of the kayak. Three or four handles (that can be used as steps also) would be quite enought and would not put too much weight or drag into the hull.

      I would suggest another test for stability. Ask some friend that has a motor boat with a nice big engine (wakeboart boats would be great) to pass closer the kayak. The waves produced by that would be good to have a tast of what you will encounter in the ocean.

      Thats it. Sorry if i told you something you already know, but its never too much when we are talking about ocean crossing, right?

      Keep up man… you are doing a grat job (as always)..

      Yuri Feres
      São Paulo-Brasil

    • Adventures of Greg on October 17, 2007

      Please do not forget that this is the prototype boat and it's main purpose is to experiment with a variety of different options.

      I don't mind the idea of a hatch in the rear, but I would kind of like that area to stay DRY. It's my sleeping compartment. The cockpit will be the semi wet area – a bit wet from water spraying into vents, open hatches, etc, so that is probably where I need to enter/exit.

      Rick wanted the door on the side of the cockpit area for the same reason you would like to see a door in the rear – to keep my weight low to avoid the use of outriggers. The advantage of a side door is it keeps the wet area wet and the dry area dry.

      That is all fine, but I will most definately need to stand up periodically, and with a door in the rear, or a door in the side, I would still require some additional stability for those rare times when I must stand up and move about. The retractable floats are intended to be used ONLY during calm conditions and never when making forward progress.


    • Alex on October 18, 2007

      I'm wondering about some form of permanent outrigger system, rather than retractable, which could give you more interior space, be stronger and give more stability too.

      Obviously there's the capsize problem with a multihull, but I'm thinking, what about a hollow float, with a self draining "scupper"?

      The idea would be that underway, the air trapped in the float give bouyancy and thus stability, but should the boat inverse, the float simply fills with water, allowing it to roll under the boat with ease. Once the boat is righted, the water drains out of the self-draining valve (it could even be forced out with the addition of a simple cabin mounted plumbed in pump), and you have two air filled, bouyant, floats again.

      Imagine it a bit like an upturned glass in a washing bowl. Trap air inside and ush down and you can feel it's bouyancy.

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