• 3rd March 2008 - By adventuresofgreg

    More sea trials:

    According to the departure countdown widget in the upper right of this page, I only have 272 days, 8 hours and a few minutes before departure. YIKES!

    I have a lot to do, but everything seems to be falling into place slowly, so I am still feeling relatively confident that I can make it to the start line in La Gomera, Spain in the Canary Islands in November.

    One of my confidence builders is more time spent at sea in WiTHiN. I really feel like I need to experience some big seas – or at the very least, I need to spend a day pedalling for 8 hours straight up and over 2 to 3 meter swells which might be considered average Atlantic crossing conditions. High winds and some chop would be a bonus.

    The keel is bolted to the seat rails which have been reinforced with kevlar and glass

    For sea trials part 2, WiTHiN will feature a ballasted keel instead of relying on ballast in the bottom of the boat. In the short video clip below, you can see how WiTHiN is thrown around quite a bit in the chop.

    We’re hoping that 40 to 90 pounds of ballast suspended 3 feet below the hull will tend to soften the rough ride. It should also provide me with enough stability to stand up, enter and exit and I can get rid of those outriggers.

    this is the keel mounting plate as viewed from below the hull. I will bed this in with epoxy and add a layer of fiberglass, then micro to fair the lip between the 1/4″ stainless plate and the hull.

    If this works, then I have faith that the new expedition boat which also uses a keel for stability is the right way to go.

    The keel tube slide onto the stub on the mounting plate and is secured with a couple of bolts. I will slip WiTHiN into the water from a boat launch, then rotate the boat onto her side from a dock. With the hatch closed, she should be pretty water tight. This will allow us to slide the keel tube (with keel ballast bulb) along the dock and onto the stub.

    In order to gauge how much weight to put in the keel, I have welded a temporary weight-lifting plate holder to the keel and I can slip on 10 to 25 lb plates onto the keel and test out stability while standing up in a pool somewhere. Once I figure out how much weight we need, I’ll weld the 3″ diameter stainless tube to the end of the keel tube and fill it with lead shot. Then I will round off the ends with bondo. It will be a bit draggy, but this prototype isn’t build to set any speed records.

    The plan is to get back to Tofino THIS MONTH for more sea trials using the new keel. I will hire an RIB for safety and head directly West out into the open Pacific for 4 hours, then turn around and head back. I should be able to make at least 50 km total.


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  • No Responses to “Sea trials part Deux”

    • "the Dude" on March 5, 2008

      That looks good, nice deep ballast should keep balance well.

      My concern: hydrodynamics of the tube and keel. You are going to be pushing that tube and keel through viscous dense fluid seawater for a whole lot of miles. Even if the water was perfectly flat and no wind, do you really want to work so hard pushing water out of the path of the round tube and keel?

      Greg, think of the dolphin, tear-drop or almond form.

      If you are mostly moving forward, then a circular tube is a disaster. Of course if you are moving in all directions, then a circular tube is required.

      3 feet of circular tube sweeping water molecules way out to the sides turbulently is 3 feet of pain you don't need.

      3 feet of streamlined 'fin' slipping between the water molecules is 3 feet of unnoticed minimized friction.

      Think of the dolphin, the huge blue whale, the whale shark. They glide through dense saltwater like an eagle through air with superb dynamic styling.

      Their body form IS circular-tubular, but 180 degrees rather than 90 degrees to their direction of travel.

      I can think of no reason at all why you would want a circular tube, rather than a fin, to hold the keel in place. Why work so hard for nothing?

      Rule: absolutely ruthlessly MAXIMISE HYDRODYNAMIC FORM of anything below the water surface.

      and then enjoy the ride…


    • David Tangye on March 29, 2008

      Dude: Think of the tube as a training device :-), its not intended for the real boat, only the 'trainer'.

      Greg: That 'chop' is tiny. Wait til you get into adverse wind against current etc offshore. Then again, its the short sharp choppy stuff that throws you round in a small craft.

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