C&C 30 Mk II rudder

[Apex]

..well this happened this weekend. On survey I knew the rudder was saturated. And after struggling with removing the rudder in the fall, curiosity got the better and I started to tackle the investigation.

I was able to confirm the rudder as straight thanks to laser level and a new set of V-Blocks. I cut the shell in half with oscillating tool. Honestly I thought I made a huge mistake while cutting because everything "appeared to have dried out". Once I had the rudder fully apart, I felt vindicated as there is plenty of water inside.

Was there a previous repair? Looks like a spray foam (open cell nonetheless) repair was made. Everything is now out. While I am trying to contact Foss for rebuild quotes I will carry on until then. Spring is just around the corner

What kind of foam has anyone on the site used for this repair? Any helpful hints in maintaining the rudder profile and rebuilding fair and straight?
Saillife and Boatworks used epoxy foam. I think that is the course. Also plan to leave a large trough for some SikaFlex or 4200 at the shaft/rudder interface to prevent water intrusion in the future.

 

[rgranger]

That looks like a lot of work. Thanks for posting. I would love to read a writeup when you get it all sorted out.

 

[shemandr]

It probably would have been helpful to have templated the rudder before taking it apart.
If you could get a scale diagram of the rudder you could loft it and make templates. You could also find another C 30 owner and template that rudder.
If the skins are in good shape templates may be moot but the first picture sort of belies that. So maybe you could template the best side.
You are not required to follow the original foil shape. A factory rudder is probably

 

[Tally Ho]

This guy has completely rebuilt his old boat. He is meticulous and has cool tools the average Joe may not have..

but watching his videos about rebuilding his rudder will give you some ideas what you are getting yourself in for..

this isn’t the first video to deal with his rudder (a previous episode deals with making a mold I think). Once you find his videos, you can find the related ones for the rudder.

A new one would be the easy (but costly) way to go unless you are REALLY handy I think.

Good luck,

Greg

 

[Apex]

@Tally Ho: Thanks, I watched Mads just last night:

using Sicomin PB250. My other option is polyurethane closed cell foam: 8# Density Foam - Polyurethane Pour Foam for Insulation and Flotation

@shemandr : Re templating, understood. I was able to confirm everything flat once I set the rudder on v-blocks, and measured using a laser level. I also used the same level to cut in the exact center. The skins look to be in good condition, and held their shape! so I may fair once complete using NACA templates.

I am still unsure about pouring method as well. Saillife held the rudder horizontal, filling in the trailing edge. The trailing edge is so narrow anyway, that glassing shut will be bonding of two layers of tape, and then cut to shape. The other option may be to rig vertical and pour in the top.

 

[Jumpstart]

I had this done professionally for my C&C 29-2 rudder. Critical that you get the right density foam. Cost me about $1500. I did final fairing myself. You will never be able to completely seal the stainless post since the post will work as the lateral forces when power reaching can be substantial. Most people drill a hole in the bottom of the rudder when the boat is hauled in the fall. Also the wrap the rudder with white paper to cut down thermal damage on the sun exposed side of dark rudders. The plug the hole before launch.

 

[Hayden Watson]

Andy at BoatWorks Today did a full series on rebuilding a foam core rudder
Part 2 is the one where he does the foam fill.

 

[smokey73]

No sure of who made the C&C 30 rudder. If it was Foss Foam you may be in luck if its a bigger job than you want to tackle. I know it was bigger than I wanted to undertake. I have a Hunter 40.5 rudder and it is currently at Foss Foam in Williston Florida for a rebuild and was just finished. I will be driving down (about 4 hours) to pick it up next week. They had the original mold for the 40.5 and explained how they would be rebuilding it. As long as the shaft is still straight and in good shape they will rebuild it for what I considered a good price vs a new one. A new one is listed at about $5000 and I was quoted $2500 to rebuild mine. I skipped the packing and shipping costs by driving it down and picking it up. Seem like nice folks. I effectively get a new rudder for half price.

 

[smokey73]

I note what looks like some pretty severe pitting on the shaft (Pic 1 far left just above some sort of fitting). Is that going to be a problem? Not my area of expertise. My shaft looked great but I could only see the exposed part above the rudder since the rudder was still intact when I delivered it to Foss foam. Worth checking into before you invest a lot of time into repair or rebuild.

 

[Apex]

@smokey73 thanks, good feedback on the rudder stock. Foss has been contacted, and they have not built a C&C30mkii (yet). I am going over options to rebuild there on the existing stock.

 

[smokey73]

Make sure you send them a picture of the existing rudder stock, with the pitting. Would not want to spend for shipping the old stock if they say the pitting I think I saw makes the old one unusable.

 

[Apex]

*update* still not much movement in this project other than planning. I am going with Mad's method on SailLife. My preference is to use Epoxy .vs. Urethane closed cell. Sicomin is available in the US through TComposites, and Tristan answered my questions promptly. the PB250/DM02 speced there is 15.6lb/ft3, and the slow hardener density is 0.98, so buoyancy just above neutral. I also found some urethane at 16lb/ft3, through US Composites. Also very responsive.

Plan: Much like Sail-Life method, except I will also be building a NACA00 (11% max chord thickness) profiled support grid to hold the two halves in better foil shape during the pour and cure process. Mads' mentioned at the end of his video to be more precise with poured amount due to residual expansion over the first 24hrs. Note taken, and this corroborated by discussions on this and other forums and rudder mfrs.