Nimbus Telkwa HV kevlar - cockpit recess hackjob

Discussion in 'Boat and Accessory Building' started by mick_allen, Jul 4, 2018.

  1. mick_allen

    mick_allen Paddler & Moderator

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    A semi-serious contemplation:

    Backstory:

    I’ve had the use of a good plastic beater [CD Sirocco] until recently but now have to give it back and needed to replace it . I like beaters - as many campsites have somewhat of a less than stellar landing situation: great barnacle enclustered knobby boulders, etc. And plus I’m not always the most careful. . .
    But I also have thought that a good quality, light but big freighter type kayak might be useful for tools, cleanup, and frivolous extras that might satisfy or maybe even assuage some family concerns about getting out there.

    And then lo and behold, this cool kevlar Nimbus HV presented itself for a price that just couldn’t be ignored. It seems semi-recent - flush hatches, great quality, great shape and sure seems lighter than the smaller Sirocco - so quite interesting. Not quite a beater, but good quality, kevlar, at a low price is virtually the same thing.

    The Issue:

    The main qualm for me is whether I should do a hackjob to the high cockpit rear that is presently at 12½” to the t.o. the coaming; the seatback [high ] is also very close to that cockpit rear: therebye really reducing comfort and layback options [let’s say for my inabilities] for rolling and self rescue.

    So the idea is to lengthen the ckpt rear by abt 2”[5cm], and drop it by about 4” [10cm] to about 8 1/2” to 9” [21.5 - 22.5cm] versus the original 32 cm high. And lengthen the rear abt 2” [5cm].

    HackjobOutline.jpg

    Of course that hackjob might be difficult as I just don’t know how easy or messy it will be to hack into that Kevlar rear deck – especially as it likely is more reinforced in just that particular area. As well, the bulkhead below is a cool bulbed shape to minimize hull stress risers for log & rock rideovers and scrambles etc. Straps might not have to be relocated, and the fittings should stay I think [need to reduce the intervention]. And of course, there’ll be the issue of the rebuild quality not even coming close to the original craftsmanship – let alone if it can even be done at all without destroying the boat, heh heh.

    Hackjob.jpg

    Anyway just a thought for now – I have other irons in the fire at this time – but it is something to contemplate.

    Thoughts?
     
  2. JohnAbercrombie

    JohnAbercrombie Paddler

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    Mick-
    Are you going to try to use the same cockpit coaming?

    A couple of years ago I did quite a bit of work on a Mariner II, including 'dropping' the rear of the cockpit a bit - not 4" though.
    Mariner II aft edited.jpg


    I had to remove a bad 'day hatch' and add a new aft hatch recess, so it was quite a bit of work..."in for a penny, in for a pound" sort of job. I used some pink foam 'sacrificial molds' and laid up most of the cockpit glass in place, as I recall. The main hatch recess was molded out of the boat and bonded into the deck.

    I made a new coaming, laminated in place.
     
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  3. nootka

    nootka Paddler

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    Maybe you don't need to layback fully?
    GreenlandPaddle2005Feb2.jpg
    p1010032.jpg
     
  4. mick_allen

    mick_allen Paddler & Moderator

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    True enough: obviously [because many kayaks have highish ckpt rear heights -and also what you demonstrate] many can deal with that situation . . . .

    but I really like options - plus a full layback has saved the bacon [for me] a few times.

    **
    the same cockpit coaming?
    I've actually hacked quite a few [glass not kevlar] coamings for various reasons - sometimes using part of the existing, but mostly laying up new ones using pieced 1" thick building styrofoam sanded to shape. The idea for this one is to cut the ckpt coaming at the vertical cut marks in the first photo, move the back part back 2", but to ditch the cutline 2" wide at first so that the final pieced layup has 8:1 epoxy scarf joins.
     
    Last edited: Jul 4, 2018
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  5. mick_allen

    mick_allen Paddler & Moderator

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    further thoughts:

    I haven't used the kayak yet, so am not so sure about lengthening the coaming - at 32.5" or so, it's not bad as is - I'm just contemplating if I don't like the cg placement. But in truth, I could probably never tell. So the issue just might be heating the coaming to a high temp after cutting the base away and seeing if it can be easily deflected downward - if not, maybe a whole bunch of vertical coaming upstand cuts on the side. . . . don't know.
     
  6. Roy222

    Roy222 Paddler

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    Mick,
    If I was to do the modification you are talking about, I would do it in two steps.
    #1 make a mold of the area I wanted to modify. Maybe 12 inches past and around the coaming.
    Use plaster, fiberglass or what ever to make the mold.
    Then use that mold to duplicate the area around the coaming I wanted to modify.
    Make the modifications to the duplicated part.

    #2 If I liked how the changes came out, then and only then, I would CUT in to the Kayak
    bond in the new surface and finish all the details

    # 3 one more thing: I would save the original cut out section - just in case

    This longer method will allow me to use the new kayak until I was ready to make the
    final CUTS.

    I would make the new surface about 1 inch wider then the hole it will cover so as to get and overlap
    joint.

    If I had the time I would make the 2 shells interchangeable and bolt on.
    If I really had a lot of extra time I would vacuum bag form the new part over a mold.

    Roy
     
  7. JohnAbercrombie

    JohnAbercrombie Paddler

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    The method I used on the Mariner II was to attach a sacrificial (pink) foam mold to the underside of the deck (after cutting out the cockpit rim completely). I then laid up layers of glass over that foam and on to the hull/deck.
    Then working from the top I ground away the unwanted deck area, revealing the foam underneath.
    The foam can easily be removed with a wire brush in an electric drill. Acetone removes the last traces.
    Once the deck recess was completed, I laminated a new coaming in place.
    Mick's idea seems like a lot less work, if the existing deck areas can be 'persuaded' to move.

    BTW, if molding from a deck shape (from above), Contact (TM) adhesive shelf plastic makes an excellent mold release.