Bad rudder cobra 850

Rhylsailer99

Well-Known Member
Joined
19 Jun 2020
Messages
776
Visit site
20201228_142648.jpgj
I just scraped some anti foul off and a whole chunk .just came loose it looks like its had a bodged repair. What kind of cost am I .looking at to get it done properly.
 
No recommendations locally, I’m afraid. I can ask around at Rhyl YC once we’ve reopened.

But don’t forget, everything is fixable (often yourself - with enough time).

A few good YouTube videos and series on rudder rebuilds... Check out ‘Sail Life’ for a rather OTT example.
 
...or just scrape out what you can, fill with thickened epoxy, glass over them and go sailing next season! It takes a lot for the tangs to escape the rudder fully, so should be ‘safe’(ish!). Plan for a full rebuild over next winter.
 
I wouldn't be going anywhere with that rudder.
We were cruising in company (luckily in good weather) with a yacht whose skipper said the steering was really difficult towards the end of a 60 mile sail, when we looked the tiller could turn freely without the rudder moving how she got into the marina I don't know. We drilled and fitted a shackle to the rear of the rudder blade and rigged lines from it, through pulley blocks and across the cockpit linking to the tiller, it got them the 60 miles back home. Would have been interesting if it had been rough.
 
...or just scrape out what you can, fill with thickened epoxy, glass over them and go sailing next season! It takes a lot for the tangs to escape the rudder fully, so should be ‘safe’(ish!). Plan for a full rebuild over next winter.
I've been told that the tangs went a few years back and it looks like it's just been spot welded and filled back in .There is a lot of rust mixed in the sponge thats soaked .
 
I've been told that the tangs went a few years back and it looks like it's just been spot welded and filled back in .There is a lot of rust mixed in the sponge thats soaked .

It's time for a proper repair! And, the way things are going, you'll have lots of time.
 
Yeah to be fair my ‘bodge it again’ suggestion was a tad rash...!

Sounds like they’ve gone in there to expose and attempt to repair where the tangs are welded to the shaft.

You should at least be able to expose the metalwork yourself for a better look. Might get lucky and find the stainless salvageable.
 
Hopefully if its a 316 grade weld it should be ok. But looking at all the rust i could see today it doesn't look good.
 
Yup, if the welds are good I’d say there’s a still chance of repairing it on the boat.

There previous GRP repair could just have been non-existent. Or they didn’t realise that water would get in somewhere else and the foam (non closed-cell, perhaps?) swelled and pushed out any attempted repair.

In the not too distant future it’s going to have to come off and be rebuild though, by the looks of how far it’s got now.
 
Even though it's stainless steel if it is getting wet with little or no air around it it will still rust. Keeping the water out is important.
 
Think I'd want that off the boat somewhere warm and dry to get it repaired/rebuilt. How much scope do you have to drop it out? Would you need to lift boat or dig a hole?

At least you found it now and not in March.

Might find help on the FB Cobra and Seawolf group as well.
 
Yes spoke to a guy in Rhyl yard im going to release it today and bring it home and leave it next to a radiator and will make it the last job so its nice and dry then.
 
We had a Cobra 850 some 8 years ago now.

She was a 1980 boat and had exactly the same problem apparently in the late 1990's. This is according to what I have heard a common failure in the Cobra range.

The then owner considered repairing, but when looking at the costs of repairing to an adequate strength or replacing completely he opted for a new rudder built onto a new stock. There were a series of photos showing the damaged rudder and the construction of the new rudder. When we took ownership in 2003 the rudder was solid as a rock. I would suggest that it is worth your while getting in touch with the owners Association LINK HERE
they may well know where the moulds are and may also have access to the uprated spec of stock and tangs.

Good luck...the 850 is a cracking boat and we had many happy hours sailing the East Coast in ours!
 
  • Like
Reactions: pvb
Yup, if the welds are good I’d say there’s a still chance of repairing it on the boat.

There previous GRP repair could just have been non-existent. Or they didn’t realise that water would get in somewhere else and the foam (non closed-cell, perhaps?) swelled and pushed out any attempted repair.

In the not too distant future it’s going to have to come off and be rebuild though, by the looks of how far it’s got now.
20210103_114444.jpg
 
Personally I'm not sure I'd bother with foam. Epoxy-based foam might hold up to the demands, but it's hard to come by and expensive.

Providing you aren't trying to fill the entire rudder and just make good the holes adjacent to the tangs, I would consider using a lightweight filler additive (e.g. microballoons) mixed in with epoxy. Using a much higher ratio than you would for a structural repair, you can bulk out the epoxy by a large margin (maybe x 3 in volume, at a push). In doing so, you are basically making a DIY epoxy 'foam'. It won't be as strong (but stronger still than most foams), but it will be water resistant and stable. You can then glass over the repair areas as normal.

Something like this, mixed in to a cheapish epoxy (EL2) together with some colloidal silica: Glass Bubbles (Microspheres) Filler Powder - Easy Composites
 
Top