Mummichog,

Your first idea is the best for quickly getting back on the water. Do a more serious repair in the off season. In fact, you do not even need to pull out the depressed core. Just enough new layers of glass to make that area strong enough. And then go paddling!!

Check out Guegon's (WEST Systems) web site, They have excellent articles on rapairs. There is no reason to strip the entire bottom. Using their advice, you strip the area of the repair, and splice in new core material (plywood) with a 8:1  or 12;1 ratio, then do the same for the outer fiberglass in that area. Then refinsh that area. No need to do the entire bottom.

Again, the West System repair notes explain it very well, with pictures. But save that for the off season. Time on the water with an ugly repair is always more important than a beautiful repair! Besides, you are the only one who will notice!!

I routinely do repairs for several Junior sailing programs and a high school sailing team. I never try to match gel coat colors - I paint repairs in a very contrasting color, ussually in siluette of a fish, shark, dolphin, crabs, racing strips.... to hide my repair work. Folks love it and have no idea there is a strong, but a little sloppy repair under the 'art'.

Sorry about your phone.

Have fun,

Joel

ouch...i feel for you.

several seasons ago, on the maiden voyage of one of my kayaks, i hit piece of submerged rebar and cut a 2 foot gash through the glass and into the core.

fwiw, i think joel, above, has it right.  do a first round repair following west system guide and enjoy the rest of your season and then a more complete repair after the season ends.    that's what i did after my maiden voyage incident and it was just fine.west system guides are pretty impressive with their discussion of repairs....they have clearly seen it all and joel knows from where he is talking.

you should be back in the water in 48 hours or less with a temp repair.

as if i didn't have enough good luck, i also had a friend accidently fumble a kayak during the season putting a nice dent in the bow.  again....temp repair to salvage the season and a more complete re-do during the off season.  

best of luck.....you will be just fine and you can totally repair any damage.

h

   Pretty much where my head was on it.  It's my wife's board (built as a gift for her)  and she said she heard the crack when she ran up on the log, but it wasn't really going that fast. Mostly it was tidal current that was carrying her.  I recall when building it that it seemed the bottom was pretty thin, only 3 mm ply with 4 oz glass.  I'm thinking, for robustness, I may put another layer of cloth on the whole bottom, even though it'll make it heavier.  Really, I'm kind of wondering in retrospect if there was a way to glass both sides of the bottom, like I did the deck, to make a proper composite sandwich for stiffness.  The egg-crate construction complicates that, though.  

The only question is whether to do the whole bottom now.  It's not the repair, it's the refinishing that'll soak up time, and to do the whole bottom will need more fairing/sanding so maybe try a quicky then collect all the materials for a new bottom later. 

yep, 

you have the engineering right....for puncture resistence, it really is more effective to put the glass on the inside...for that proper composite sandwich.

in hindsight, you can always glass the inside even if clc does not call for it.  there are a couple stitch and glue designed kayaks, for example, that glass the inside vs just painting with epoxy.   fwiw, clc is typically pretty good about sorting out a good build that is sturdy.....and the kaholo's have been around for a while and it has been a best seller with lots of them built.  clc, i think, does a pretty good job of knowing how their fleet is performing.....so i don't think the design is particularly problematic.

so its also possible to take the perspective that its just fine as designed and you just had an unfortunate accident.....and accidents happen and becuase you are a builder, you can fix accidents and get a result where most people will never know that a repair was even done and it only cost you some of your time....not a bunch of dollars.

in 25 years of paddling (and i paddle a lot each season)  i only hit rebar once and only dropped a boat once..... so only two times in hundreds of outings did i need to stop and go do a repair.   each time, like you i thought about reinforcement and how to prevent it from ever happening again, but when i calmed myself and though about it vs how much i enjored a light, build it yourself boat, i just stayed with the original approach.   maybe its not that bad an idea?

h

   I'm sure the 3mm panel thickness is well considered.  You are trying to get a light hull that will do the job, and the bottom normally is supporting the weight of the craft and load by the evenly distributed pressure of the water across the whole surface, so a heavy panel that can point load isn't rational.  Even when you land one on a beach, the sand/mud will generally provide a well distributed loading.  Even without much impact, run the board up on a single knot on a log, and the weight of the paddler puts an unreasonable amount of force on a very small area.  One of the "manure happens" things that is outside the original design scope.

I've sanded it out, put a screw through a wood block and into the depressed part to pull it out (mostly) and started w/ some filled epoxy in the screw hole and around the edges to give me a little "dish" to work with.  Tomorrow I layer in some bits of glass and cover over with a big enough piece to tie it together and give me the space to feather it out.  Once the dark blue paint goes back on, it should be presentable from 10 feet.  Besides it's facing down in the water and the fish ain't picky.