rudder separation / repaid advice

First time out on my new (to me) cat this past weekend and rudders hit bottom 1 time (seemingly gently) on the way in the pass (trying to shoot the "cut through")

My new rudder seems to split a bit.

I was thining of using a dremel to grind it out a bit and use some west system (with 403 i have sitting around)


looking for tips and advice

It's hard to tell but that looks "paint colored" inside the crack...if that is the case, it's been that way for longer than your last sail.

Regardless, on the tip like that, it's probably fine just to fill and fair it. The 403 will be good for that.

thanks

I would rather go for West 406 colloidal silica in this case of rudder repair.

406 gives a tougher resin compound with more abrasion resistance. It's a fraction heavier but that plays in your case no part. Only disadvantage is that it tends to be a bit more stiffer when applying. But if you use less, you can make it butter-like.

So be sure to fill the gaps and tears fully!

do you think i need to dremel it out first or just syringe the epoxy/filler in and clamp the rudder tight?

The key is always: get rid of the loose parts.

The foam inside has to be dry and has to be consistent. It's function is holding the two ruddersides of laminate at the fixed and proper distance.
This will lead to the resistance against flexing of the rudder and resistance against impact on the sides by obstacles.

If the filler compound is thin, then the foam maybe can suck some filler compound. But the foam has to be non 100% closed-cell for that.
So in this case it will make the need for the dremel less.

But if the core is 100% closed cell (test it with a "suction-kiss"), you better dremel it out carefully.

Like northsea said, you do need to clean up any loose bits first. If I remember correctly, you are sailing a Nacra? The cores they used in older foils are a solid resin based substance and you won't need to do anything weird with it - water migration is not a serious concern. You are also at the tip of the foil where there is not much stress to worry about (other than future hits against the bottom). I would just clean out any loose pieces, fill it, and sand it fair. It will hit bottom again sooner or later and need more attention again.

Filler is a bandaid dude. You will drag those rudders against the bottom again, i'm guessing. You could make like a tail block that they sometimes put on long board surfboards and glass that on. You would have to grind down the sides of the blade near the repair so that after you fair the glass job down, the repair material will still be there.
Band aid also fine just not great at stopping the splitting once you hit again. If you had 1 spare rudder you could take some time doing the repair and not miss sailing days.

Mystere 6.0
these rudders were purchased new a few years ago from mystere, and not used much (previous owner is a good friend of mine, i know the boat and its usage very well)

tail block?

Yeah, lost me on that one too.

Mystere...aaa...that's right. I believe Mystere used the same type of core system. There's no harm in making a quick patch and then keeping an eye on it. It's not like you own an infusion and the embedded forestay bridle attachment block is currently coming loose inside the hull and breaking the exterior fiberglass and gelcoat skin or anything. THAT you wouldn't want to just patch and see.

a tailblock is a reinforcement at the edge of a board, or a rudder, skeg, daggerboard etc. Mostly made of hard-wood.

The trick is that you glue and shape this piece of wood before the lamination. So it's embedded in the final shape of the concerning part.

It will make the edge (= tail, tip, etc) more resistant for abrasion and you have created a "zone for sacrifice".

film tailblock

I used this method already for decades of years in my surfboard fins and also in my home made catrudders.

thanks

This tailblock method works at best if you use it on forehand. So in case of a ruddertip: you implant the hardwooden tip before covering the new shaped rudder with fibres/resin.

But even later on, like in your case, you can sort of use the same method:
Make a nice clean oblong hole with your dremel in the tipside of your damaged rudder. Then you fill this with rather stiff and hardened compoundpast (so made with use of colloidal silica powder).

This can ofcourse only work if the sides of the rudder are not too much damaged.
But even then you can laminate a small peace of the side part again with a "slanting joint".

You have then also created a tailblock on the ruddertip, but not of wood, but of epoxycompound. This will certainly be more resistant to abrasion and bottom crashes.

And you can repeat this procedure again infinite.

cool thanks
good video too!

With the help of Ellie's sailing shop ... we cleaned out the wound and created a slot

I laid up some epoxy and cloth and epoxied it inside the slot we created



dremeled it down to a close shape


faired the repair in



Then i dropped both rudders on the ground when the i kicked the table/horse leg - now i had 2 rudders to (re) repair ...


added some gelcoat


and painted

went sailing and immediately sailed too far out and and hit bottom - only chipped off a little paint

thanks for the input and help to all