Sunday, December 5, 2010

Plan B and the rubbing strip.

A great week-end for epoxy, despite the odd bit of tropical rain, I managed two lots of double- wet-on wet coatings for the hull, embedding then covering the fibreglass matting. The wood looks delicious....

Months ago, I decided that I wouldn't add a lower rubbing strake, figuring that I liked the contours without them, but also realising that these things seemed to exaggerate any unfairness in the sheer and the top board. Then, after epoxying the hull, my normal infatuation with the various colours of timber kicked in, and I started fantasising about varnishing the hull- which, after all, would be facing down, away from the sun most of the time. The next step in the process of thinking this through was to remember how nasty the Ozzie sun can be and how enthusiastic most woods are to turn grey from exposure, unlike people, who turn red. I didn't want to have the first boat with a melanoma, so I started thinking that maybe the top strake could stay woody (despite the fact that I made no effort to choose the prettiest boards or take any particular care in the board joints)....but that required a lower rubbing strip. So, plan B it is.
The spars are a lovely bit of work to do, and so far there is a mast, a main boom and above, the mizzen glue-up has been done. Because this is a thinner spar, I took extra care in laying it out straight, even clamping along a straight edge and using a stringline, but I have to say the fairies got into my shed overnight and just gave it a 2-3mm kick to one side over the 3.6 metre length. I can accommodate this though because I made the material a little thicker for the glue-up, and the taper can be off-set a tiny bit to compensate for the bend. I still need to glue the yard and gaff jaw pieces, do a heap of rounding, and then the mizzen boom and boomkin. Rudder, foil and tiller bits are sort of organising themselves while the spars are happening.

10 comments:

  1. Interesting. I very much like a rub strip but wouldn't necessarily associate it with a varnished sheer strake. Though I understand how that idea developed, I've seen plenty of pretty boats with a varnished sheer stake and no rub strip.
    Just offering this as a counterpoint - I vote for the rub strip - beauty is in the small details. The contrast of the sheer line to the line of the bottom of the shear plank is the most important element, in profile. The most striking design element of a Welsford or a Oughtred boat is the shape (and pitch) of the sheer strake.

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  2. Thanks MB- you are spot on as usual, my worry is that the line will also reveal and amplify my wobbles and bumps! But I'm doing it, one is already glued on.

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  3. (1)Let the strip form it's own fair line and fill with epoxy as necessary. Use wood dust in your filler and no one will be the wiser. I won't tell.
    (2)The other way to make it work is sand the strip with a long board so it changes depth (thickness) when necessary. (Mirror image of above).
    (3) You worry too much. It's probably nearly perfect (knowing you).

    doryman

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  4. You'll be glad of those rubbing strips the first time you come alongside a dock or pontoon.

    I added rubbing strips to my Oughtred Whilly Tern, as I wanted to varnish the shear-strake. I thought it would look too wide so I run the rubbing strip half way down which tricks the eye into thinking the shear-strake is much thinner. On my Wostenholme Coot the planks are narrower so I ran the rubbing strip along the bottom of the shear-strake, it gives added protection and a neat line where the colour changes. Your build is coming along great, good to see someone making progress as we freeze over here.
    Cheers Graham.

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  5. Right again MB, life is all about living with bumps and wobbles.
    I'm using a quite fine strip about 5mm deep and 20mm high.

    Thanks for chipping in Graham, yours are beautiful examples. I did consider using the strip higher on the sheer plank too, but it would then have been too small relative to the others, I think.
    I thought a bit about my Very Northern Friends on the week-end. It has suddenly become quite warm, but still unnaturally wet. Weather is ANOTHER thing I worry too much about Michael!

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  6. Too many things to comment on but things are moving along well Rob, great stuff.

    Good idea using the scratch-stock I'm about to start filling and sanding the ply and intended to sand the plank edges with a shop made purpose built no expense spared sanding block.

    I like the scratch-stock idea better.

    Cheers
    Mike

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  7. The wood is indeed looking delicious!!!

    But to suggest that my dad would worry????


    xx

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  8. Looking good. Great photo with the string line showing what the fairies have been up to! Do your plans specify an outer fibreglass sheath or is that some thing you have added for wear resistance? How do you go glassing over the lap joints?

    http://licensed2tinker.yolasite.com/

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  9. Hi Pablo, the plans specify matting over the bottom panel, the garboard, and up to the first overlap. That bottom edge is a butt joint. As you say, it is mostly for abrasion resistance.
    And by the way, what ever happened to Good Fairies? You know, the sort that would finish tedious jobs while you are at dinner....

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