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  1. #1
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    Default Building "shoe" for Spike (Oughtred Design) = Convertible skiff to sail-motor-sail...

    Just started to build a shoe for my sailing-skiff. It is a Oughtred designed Spike.
    This 12 feet boat sails and rows very nice and I use it with this modes on Alpine lakes.

    At the Lagoons of Venice I prefer an Outboard. Want to use same boat for that. Adapting the Transom for Spike (5 HP Mercury Outboard) has been my first approach but boat is not performing well in motor-mode. This is due to the rocker of bottom and because of slim beam aft. It runs some 10 km/hour but with high nose. Balancing with some weight helps, but not satisfactory.

    As I want to use boat also in sailing mode, I am building a "shoe" for the boat, elongate the boat by some 2 feet with a wider and more vertical transom and a straight edge aft, for better dynamic-hydraulics.
    This shoe will be bolted temporarily onto the Spike and should be possible to dismount in minutes.
    Boat will be fully convertible between modes.

    Here some pictures showing progress up to now.

    Gua-Riva.jpgDSCN0270.jpgIMG_20190223_103459.jpgIMG_20190227_153041.jpg
    Attached Images Attached Images
    Last edited by Pateplumaboat; 03-27-2019 at 04:04 PM.
    Hay mas tiempo que vida!

  2. #2
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    Default Re: Building "shoe" for Spike (Oughtred Design) = Convertible skiff to sail-motor-sai

    Some more progress-pictures:

    Boat turned over todayIMG_20190324_114003.jpgIMG_20190324_114142.jpg
    Hay mas tiempo que vida!

  3. #3
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    Default Re: Building "shoe" for Spike (Oughtred Design) = Convertible skiff to sail-motor-sai

    Checking Transom-Geometry with outboard in correct height (Cavitation-plate 1-2 inch below bottom of transom).
    Work in progress.
    From now on internal works in "shoe". Transom still to be shaped for better look, will be done later.


    IMG_20190325_172726.jpgIMG_20190325_172756.jpgIMG_20190325_172816.jpg

  4. #4
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    Default Re: Building "shoe" for Spike (Oughtred Design) = Convertible skiff to sail-motor-sai

    I have seen a permanent flat transom put on a canoe stern in the UK to comply with racing rules.

    How will you waterproof the extension, while keeping it changeable?

  5. #5
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    Default Re: Building "shoe" for Spike (Oughtred Design) = Convertible skiff to sail-motor-sai

    Hello lupussonic,
    I will fill shoe between extension and original Spike for about 2/3 of height with PU-foam (glued panels and expandable PU gun-fill foam) to avoid dead water (eddy water).
    Hay mas tiempo que vida!

  6. #6
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    Default Re: Building "shoe" for Spike (Oughtred Design) = Convertible skiff to sail-motor-sai

    Does it need to be watertight? As long as the water can get out again, why not let it flood? Put a hole in the bottom, covered with a piece of sheet metal, to create an Elvstrom-style bailer. It will drain once the boat is moving, and drain really well when on a plane.

    Tin skiffs used to come like this. Now, they have a hole in the transom, that never gets rid of all the water.

  7. #7
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    Default Re: Building "shoe" for Spike (Oughtred Design) = Convertible skiff to sail-motor-sai

    Hello robm,
    it does not need to be completely watertight, but I have to avoid "dead water". If I would leave "shoe" without foam such dead water would hinder my boat to go into gliding-mode if used with motor. Assume 4 inch height of dead water: This results in about 120 liter of water, equals 120 kg of additional load to boat and therefore 120 kg loss of uplift and I would loose effect of wider stern of boat helping me to glide with small motor.
    Last edited by Pateplumaboat; 03-25-2019 at 05:51 PM.
    Hay mas tiempo que vida!

  8. #8
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    Default Re: Building "shoe" for Spike (Oughtred Design) = Convertible skiff to sail-motor-sai

    Boat without "shoe". Outboard on Spike´s transom. Transom adaptor-plate installed to allow for higher level of cavitation-plate and to compensate very inclined transom of skiff.
    DSC01021 (2).jpg
    Hay mas tiempo que vida!

  9. #9
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    Default Re: Building "shoe" for Spike (Oughtred Design) = Convertible skiff to sail-motor-sai

    An interesting project. I'll be following your progress. Best of luck with it.
    -Dave

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    Default Re: Building "shoe" for Spike (Oughtred Design) = Convertible skiff to sail-motor-sai

    Setting up for motor-splash-well

    IMG_20190328_130326.jpg
    Hay mas tiempo que vida!

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    Default Re: Building "shoe" for Spike (Oughtred Design) = Convertible skiff to sail-motor-sai

    Today: Precut transition-cover-planks

    IMG_20190329_101130.jpg


    IMG_20190329_101325.jpg

    IMG_20190329_101141.jpg

    Not yet glued. Will have to paint/seal wood under well and cover-planks and fill void with foam.
    Last edited by Pateplumaboat; 03-29-2019 at 12:18 PM.
    Hay mas tiempo que vida!

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    Default Re: Building "shoe" for Spike (Oughtred Design) = Convertible skiff to sail-motor-sai

    My intention is to use XPS foam boards combined with "window/door-foam" to fill room between "shoe" and original/unchanged boat (Spike).
    XPS board will be cut to size and glued together using foam. Smaller voids will be filled with window/door-foam, separating temporarily with polyethylene-sheets . Any doubts? Will this work? Any thoughts regarding material-quality (salt-water-resistance, water-absortion...) of window/door-foam?
    Hay mas tiempo que vida!

  13. #13
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    Default Re: Building "shoe" for Spike (Oughtred Design) = Convertible skiff to sail-motor-sai

    Second application of paint inside of "shoe" today:

    IMG_20190331_154456.jpg

    Dagger-Board-Case needs to be covered for outboard-modus, as water would spill into boat without seal. Needs to be quite watertight due to pressure building up from slot below. Problem solved combining wider seat with closure of slot. Work in progress as I intend to cover slot also at bottom of boat.

    IMG_20190331_173218.jpg
    Last edited by Pateplumaboat; 03-31-2019 at 12:38 PM.
    Hay mas tiempo que vida!

  14. #14
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    Default Re: Building "shoe" for Spike (Oughtred Design) = Convertible skiff to sail-motor-sai

    Guess: For what this could be for?



    IMG_20190401_110938.jpg
    Hay mas tiempo que vida!

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    Default Re: Building "shoe" for Spike (Oughtred Design) = Convertible skiff to sail-motor-sai

    Hi

    Daggerboard Plug obviously.

    i like this kind of "swiss army knife boat approach"

  16. #16
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    Default Re: Building "shoe" for Spike (Oughtred Design) = Convertible skiff to sail-motor-sai

    Quote Originally Posted by koederfischgriller View Post
    Hi

    Daggerboard Plug obviously.

    i like this kind of "swiss army knife boat approach"

    Congratulations koederfischgriller, hello Bavaria!
    Yes, this is the lower part of the daggerboard-plug. Upper part (see picture below with all parts) will be used as an additional (wider) seat for passenger. Parts will be connected using stainless steel-bolt in such way, that change to sailing-mode (with daggerboard) will be an issue of five minutes.

    IMG_20190401_165659.jpg
    Hay mas tiempo que vida!

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    Default Re: Building "shoe" for Spike (Oughtred Design) = Convertible skiff to sail-motor-sai

    Quote Originally Posted by koederfischgriller View Post
    Hi

    Daggerboard Plug obviously.

    i like this kind of "swiss army knife boat approach"
    Changed daggerboard-plug for a more robust solution. This allows to install plug top-down:

    IMG_20190417_151617.jpg

    Fwrd-bracing of daggerboard-case changed. Will need still some bracket and finish-work:

    IMG_20190417_150528.jpg

    Daggerboard-slot viewed from bottom up:
    IMG_20190417_150441.jpg
    Hay mas tiempo que vida!

  18. #18
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    Default Re: Building "shoe" for Spike (Oughtred Design) = Convertible skiff to sail-motor-sai

    My only concern is how the leading edge of your addition will be fixed, if at all? Im thinking water pressure acting as a lever if that is only fixed using bolts aft. Interesting project though.

  19. #19
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    Default Re: Building "shoe" for Spike (Oughtred Design) = Convertible skiff to sail-motor-sai

    Quote Originally Posted by skaraborgcraft View Post
    My only concern is how the leading edge of your addition will be fixed, if at all? Im thinking water pressure acting as a lever if that is only fixed using bolts aft. Interesting project though.
    Thanks for comment, skaraborgcraft. Here my thoughts:
    Leading edge will be fixed with two 4mm stainless steel-bolts penetrating Spikes frame nearest to leading edge. Anyway shoe is constructed in that way that shoe-planks have already slight tendency pressing inside to cheeks /planks) of Spike. Also one bigger bolt (with watertight seals) drilled through keel of Spike and keel of "shoe" will be installed, located about 4 inch fwrd of Spikes aft flotation-chamber.

    Transition of edge with Spike will be done using special rubber-seal (see screenshot) fixed/glued onto side-planks. Member "koederfishgriller" suggested ducttape. Technically this would work, but would not look quite salty. My target is to make "convertible boat" feasible (with my shoe-idea), but also optically outcome should be a "nice boat".
    Anyway, thanks for any suggestions from members.

    Rubber seal.jpg
    Hay mas tiempo que vida!

  20. #20
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    Default Re: Building "shoe" for Spike (Oughtred Design) = Convertible skiff to sail-motor-sai

    Ducktape will do!

    just to be sure: don´t forget the camera for the first trial run! You might become a youtube Star!

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    Default Re: Building "shoe" for Spike (Oughtred Design) = Convertible skiff to sail-motor-sai

    Today started to fill starboard aft-part of "shoe" with XPS insulation-panels glued together and void-filling with perimeter-glue-foam.
    Used mainly 8 cm (about 3 inch) thick XPS panels to avoid voids as far as possible.

    IMG_20190402_144724.jpg

    IMG_20190402_153914.jpg
    Hay mas tiempo que vida!

  22. #22
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    Default Re: Building "shoe" for Spike (Oughtred Design) = Convertible skiff to sail-motor-sai

    The expanding PU foam is not very waterproof over time. It will eventually absorb water, and it will not readily dry out.

    Since you are using it only to fill in the cracks between and around the EPS, this may not be a huge problem. However, if you try to use the pour-in-place foam only, it will eventually get wet, stay wet, and your flotation will be useless.

    Keeping the water out is a good idea, but I believe it is not necessary. Your boat would not leap onto a plane, but, with a good bailer design, the water would eventually drain out and then it would get up and go. It takes surprisingly little time to suck a boat dry with an Elvstrom style bailer.

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    Default Re: Building "shoe" for Spike (Oughtred Design) = Convertible skiff to sail-motor-sai

    Quote Originally Posted by robm View Post
    The expanding PU foam is not very waterproof over time. It will eventually absorb water, and it will not readily dry out.

    Since you are using it only to fill in the cracks between and around the EPS, this may not be a huge problem. However, if you try to use the pour-in-place foam only, it will eventually get wet, stay wet, and your flotation will be useless.

    Keeping the water out is a good idea, but I believe it is not necessary. Your boat would not leap onto a plane, but, with a good bailer design, the water would eventually drain out and then it would get up and go. It takes surprisingly little time to suck a boat dry with an Elvstrom style bailer.
    robm, thanks for comment. Interesting discussion. Usually I am keeping my boats most of time out of water, light boats are easy to take out with a small trolley and winch. If I go to the Lagoons of Venice I usually keep boat in the water for max. 10 days or so. I assume the foam will not suck too much in this 10 days. If not I will have to take out boat with trolley. XPS (closed cell insulation!) panels (not EPS! EPS is not closed cell insulation) are used in construction for housing as perimeter-insulation below ground and will absorb only small amounts of water. This panels are specially for under watertable-use below ground where is always humidity and those panels should keep there insulation-specs also if exposed to water. I will use only very limited amounts of pour-in place foam for gluing panels together and keep on place, therefore the amount of water absorbed will be negligible.

    I understand that an Elvstrom bailer would bail out boat if boat is already in gliding-mode. But there is the problem: If my "shoe" would be filled with water boat has less uplift and lots of "dead-water" before an Elvstrom bailer, which works only if boat is already in sort of gliding-mode, can bail out this water. As my Outboard is only 5 hp, it would be difficult to bring boat into gliding mode with all this water sitting there. This issue of power for motor gets even more problematic if electric motor (Torqueedo?) will be in use.
    Hay mas tiempo que vida!

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    Default Re: Building "shoe" for Spike (Oughtred Design) = Convertible skiff to sail-motor-sai

    One more reason why I opted for this solution is safety. Boats from Mr. Oughtred are excellent designed and very light boats. My Spike does have upper and lower side-planks with only 5 mm high-quality Sapeli-Mahagony-ply. On one of my other boats (Amberjack/Sickleback-Dory), once I hit a pile with speed of about 8 km/h rowing in a River with current, side-plank broke away and gunwale split, and my boat (and my passengers, all with live-vests!) sunk in seconds. I repaired the boat, but added buoyancy chambers (according to options shown in Oughtred drawings). But, I think, even better than watertight airfilled flotation-chambers is to fill them up with solid buoyancy. And this is what I learned from this and other capsizes I experienced.


    Today: Aft part of "shoe" filled up with XPS-panels glued in place.
    Next step: plywood cover and sides to form outboard-splash-well.

    IMG_20190403_153549.jpg
    Hay mas tiempo que vida!

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    Default Re: Building "shoe" for Spike (Oughtred Design) = Convertible skiff to sail-motor-sai

    Scuppers cut out and plywood-covers for outboard-well glued:

    IMG_20190404_123459.jpg


    Guess: what is this?

    IMG_20190404_124021.jpg
    Hay mas tiempo que vida!

  26. #26
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    Default Re: Building "shoe" for Spike (Oughtred Design) = Convertible skiff to sail-motor-sai

    Excellent. I commend your ingenuity and enthusiasm!

    Looking forward to seeing more.

    Kevin
    There are two kinds of boaters: those who have run aground, and those who lie about it.

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    Default Re: Building "shoe" for Spike (Oughtred Design) = Convertible skiff to sail-motor-sai

    Adapter-plate (bbrd of transom) in case long-shaft-motor will be used (Will borrow Torqueedo Travel 1003 L /about 3 hp/ to test this boat on Alpine-lakes where gasoline-engines are not allowed):

    IMG_20190405_092424.jpg

    Foredeck cut, not yet varnished. Covers XPS-buoyancy-panels (alternative to air-chamber in foredeck as per Mr. Oughtred´s design):

    IMG_20190405_195007.jpg

    Outboard-motor stand biult using hand-truck and scapwood:

    IMG_20190405_165404.jpg



    Quarter-knees and transom-reinforcement panel glued:

    IMG_20190405_192223.jpg
    Hay mas tiempo que vida!

  28. #28
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    Default Re: Building "shoe" for Spike (Oughtred Design) = Convertible skiff to sail-motor-sai

    Two 8 mm Bolts connecting transom of Spike with "shoe":

    IMG_20190407_123300.jpg

    IMG_20190407_114342.jpg
    Hay mas tiempo que vida!

  29. #29
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    Default Re: Building "shoe" for Spike (Oughtred Design) = Convertible skiff to sail-motor-sai

    Boat turned over again:

    IMG_20190407_142425.jpg

    Weight of boat including shoe: 44 x 2 = 88 kg

    IMG_20190407_142055.jpg

    Next problem to be solved: Transition of bottom, between Spike and fwd-edge of "shoe":

    IMG_20190407_142449.jpg
    Hay mas tiempo que vida!

  30. #30
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    Default Re: Building "shoe" for Spike (Oughtred Design) = Convertible skiff to sail-motor-sai

    Elements for transition between Spike and fwd-edge of "shoe":

    IMG_20190409_122701.jpg

    Temporary assembly-check:

    IMG_20190409_121606.jpg
    Hay mas tiempo que vida!

  31. #31
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    Default Re: Building "shoe" for Spike (Oughtred Design) = Convertible skiff to sail-motor-sai

    Wow! Great building! Really love your boat!

  32. #32
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    Default Re: Building "shoe" for Spike (Oughtred Design) = Convertible skiff to sail-motor-sai

    "Winglets" (pushing down triangular transition plywood panels) and center U glued:

    IMG_20190410_103651.jpg
    Hay mas tiempo que vida!

  33. #33
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    Default Re: Building "shoe" for Spike (Oughtred Design) = Convertible skiff to sail-motor-sai

    Shoe turned over. Weight of shoe as today: 35 kg. Ok! I can handle this weight alone.

    IMG_20190412_183642.jpg

    Remaining steps:
    - Clean inside
    - Trim cheeks
    - Glue fillets inside of shoe
    - Paint inside
    - Glue foam-panels fwrd of frame
    - Foam-fill remaining voids from top (liquid two-components-PU-foam)
    - Turnover shoe and put again onto mothership. Fix three bolts again
    - Turnover boat
    - Install and glue top-panels
    - Sand and paint/varnish all visible parts of shoe
    Hay mas tiempo que vida!

  34. #34
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    Default Re: Building "shoe" for Spike (Oughtred Design) = Convertible skiff to sail-motor-sai

    Took off shoe today.

    Bottom-transition ready:

    IMG_20190412_115026.jpg

    IMG_20190412_121158.jpg


    Remove three botls and haul backwards:

    IMG_20190412_165147.jpg

    Shoe slips off:

    IMG_20190412_171254.jpg

    Shoe is free:

    IMG_20190412_171528.jpg
    Hay mas tiempo que vida!

  35. #35
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    Default Re: Building "shoe" for Spike (Oughtred Design) = Convertible skiff to sail-motor-sai

    Hay mas tiempo que vida!

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