Cut thru fiberglass at bow

I was applying my first skim coat and while admiring my work I noticed at the bow I had sanded thru and had bare wood showing where the bottom and side panels meet.  I assume I need to add strips of fiberglass at the bow but worry that I won’t be able to feather the fiberglass in without it being noticed. Is this a common occurrence and is this an easy fix?



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RE: Cut thru fiberglass at bow

Yes and yes.

If you work with care it'll be totally invisible. If it ends up visible to the point where it bothers you, you can always paint the bottom a nice contrasting color with the border coming up over the glass repair. In fact, I deliberately do this on my boats  with graphite/epoxy mix to protect the seam from abrasion.

On my WD12 here, the graphite/epoxy runs up from the bottom to just over the stitch holes. It protects the hard chine where it's most likely to rub against anything and hides the filled stitch holes. It would also hide any glass repairs at the edge that weren't quite invisible.

If you want a better chance of the invisible feathering working, you can practice with wood and glass scraps before you try it on the actual boat.

Somewhere on this forum (I haven't got time to do all the searching) Silver Salt gives a tip for invisibly feathering that involves thinning the edges by removing every other thread before laying up and sanding.

Another way to get a good clean edge is by outlining the repair area with clear plastic packing tape. Overlap the patch onto the tape. It will stick to the wood, but not the tape. Once it cures to non-tacky and a rubbery thick leather texture (the so-called green stage), you can peel it off the tape and cut it where it joins the wood. Lightly sand the edge to smooth it, then paint it with more epoxy to cover the transition. Sand when cured.

Good luck,


RE: Cut thru fiberglass at bow

As Laszlo said, yes and yes.  it's very common to sand through in these areas.

fwiw, for most of the construction manuals i have for boats i have built, they suggest as many as two additional layers of 4 oz cloth (from leftovers from the hull or deck glass)  from the bow/stern, across the knuckles and a foot or two inward along the hulls towards the center of the boat. 

the picture at this link gives a good perspective on how to do this:

when i build, i usually add two layers and will do one piece that is approximately 5 inches wide and then the final piece 4 inches wide...centering them with the wider piece laid first and the 4 inch piece on top of it.  i have had no issue with these wetting out clear.   it is also important to do the fill coats on these pieces with an additional coat or two of resin to fill the weave.

once this has cured, i sand with a stiff sanding block by hand to feather it in.  i have not had anybody be able to notice the additional glass.  it is very easy to accidently sand through at these edges so hand sanding and going slow pays off.    

i hope that helps


RE: Cut thru fiberglass at bow

   Yes! to cutting your own "bias" cloth for wrapping the stem.  I did that for my skerry and SUP because using cloth cut squarely always seems to create puckered edges where it wraps over the stem (goes in 2 directions at once).  I got so frustrated with it on my skerry, it was still wet so I cut back from the bow to where it lay flat, peeled that wet fabric off and immediately went to my scraps to cut bias bits and doubled them up on the skerry.  BTW, have sharp, clean shears to cut it because it will want to pull and unravel if you have poor shears.  And avoid dabbing on it with a brush any more than needed when wetting out because again, those threads will pull up.  I wound up using my hands to smooth it...with gloves of course.

RE: Cut thru fiberglass at bow

Guys I appreciate this information. I have been thinking of alternatives to glass, even thinking of adding a keel. I am working on both a WD12 and WD10 and I will use the fiberglass tape from the WD10 kit and I like the idea of doubling up the tape. Again thanks for the help.   

RE: Cut thru fiberglass at bow

   I am painting the bottom with white paint and I like the idea of working up the paint to hide the extra thickness the added tape will cause.

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