Splitting Rudder

[harryb1]

Hi all,

I would appreciate any advice anyone can give on the following:

I have just dropped the rudder off my Vivacity 24, realising repair was going to be necessary when the rudder no longer turned with the tiller!

I suspect the only reason can be the tangs have corroded away from the rudder post within the rudder, so my next job is to split the rudder open, not quite sure where to start and the best way of doing this neatly so that it can be put back together.

What am I likely to find once open? How should the tangs be fixed to post?

It looks like water could have found it's way in around the post at the top, so I guess this has caused the corrosion, but will I have more problems with wet grp, or will a good drying out be ok before putting back together? What's the best way of reasembleing and sealing the rudder?

Thanks in advance.

 

[mandlmaunder]

SSTTOOPPP!!
if you split your rudder be prepared for muchio big rebuild.
if you know how to take a mould first then as,if and usually when the fan is splattered you can make a new 1 .
my recommendation would be to go to plan B first as that is probably where you will end just because of the law of sailing(if there is a cheap way and an expensive way , you try the cheap way first then do right anyway).
This time make the whole rudder from GRP(heavy on the resin) no corrosion , should last forever

 

[Poignard]

There was an article in PBO a few years ago where somebody described repairing a rudder. I got rid of all my old copies but someone on here may have it, or maybe you can get a back-issue from PBO.

 

[jeremyshaw]

Me, I'd think about whacking a few bolts through so I could, with luck, enjoy the vestigial summer, then spend the winter doing a proper job as Mr. Maunder suggests.

 

[johnlilley]

Hi, might be easier than you think. use an angle grinder with cutting blade (much thinner than grinding blade) cut one face away, as in the photos of this link http://seasurveys-photos.mysite.orange.co.uk/ & http://seasurveys-repairs.mysite.orange.co.uk/ Best to try to ensure you cut the face that is NOT bonded to the tangs, hammer testing will likely highlight these areas.

Remove all PU foam.

Expose the tangs, probably steel rods pushed into bronze shaft and glassed to inner face, remove them & replace with better quality, grind all rubbish away, Prepare all internal areas for new layers of epoxy resin and glass cloth to bond rods to the inner face.

Repair any other damage.

Bond small fillets of ply to the underside of the exposed hole in the rudder that stick out like supports, lay the cleaned, cut away face on these with temporary bonding to just keep face in position and run a few laminates of epoxy & glass tape or cloth around the join after grinding a shallow saucer shape recess around the join to allow build up to correct level.

Run a fillet of polyurethane around the entry point of the stock and overlay this with a layer of glass & epoxy resin.

Each rudder is different but generally this would be satisfactory if done properly.

John Lilley

 

[harryb1]

Hmmm,

Thanks guys, Lots of different ideas there- I was thinking this might turn into bigish rebuild- hadn't considered taking a mould though.

Had considered quick bodge of bolting to post for a temporary fix, only way I can think of is to drill through post at 90deg to ruddder, but do I want to damage and weeken the rudder post for a quick fix?

John's advice is along the line of what I thought I might be in for. Chipping away at the grp around the post exit at the top I can see solid but soaked wood- is this likely to be a frame on which grp is laminated filled with foam, or a more solid wooden rudder encased in grp? It's very heavy, but I guess either wood or water filled foam would be.
This wood would need drying out or replacing I guess, maybe making a mould would be quicker!
I have seen some photos along with your excelent ones which suggest opening up the port side, the tangs being laminated to the starboard side, is this likely to be convention on different rudders?

Many thanks, anybody else who has experience of this greatly appreciated

 

[oldsaltoz]

G'day Harry, welcome to the YBW forums.

Broken tangs are not uncommon, corrosion or poor design are the top 2 causes that I see.

I would not be too keen to salvage any of the existing glass or timber, it's either rotted or perforated. However it can save some time, if you do want to use them; start by cutting all the way around the edge and just under the top when you get to the shaft.

The above halves should be ground down to about one half or the original thickness, ensuring all paint is removed from the outside and the inside should be ground to a fresh finish with no discolouration.

The important points to remember when re-building are:

Any welds on stainless steel Must be treated (Pickled) to prevent corrosion.

Tangs must have solid support to rudder case.

Lay one half on the bench and clamp the rudder with shaft and new tangs level, you may have to chock both ends of the shaft.

Place one of the outer halves under the shaft and mix some epoxy resin and micro fibres, form a cone between the old glass and the tangs underside, repeat this along the tangs so the base of the cones on the old skin are about 2 inches apart. Let this cure, then add Closed Cell Micro balloons between the cones to form a single slope from the tang to the rudder skin, let this cure then add 4 layers of bi-directional cloth (Not CSM) over the chevron and onto the old glass, overlap each layer by 1 inch or more if you have the space, let this cure.

Now drill 6mm holes in the remaining rudder side at about 1 inch apart on a grid pattern, this will allow any air to escape when we close the rudder; Mix a batch of closed cell balloons and apply to the now cured lower section, the objective here is ti have enough material to fill the void, place the second half on top and press down letting any excess balloons exit via the drill holes. Make sure the overall shape and edges are close.

Add 2 "0" rings at the top of the rudder on the shaft, coat them with a little Vaseline on the shaft side only stop the resin sticking them, then layup the required depth of glass.

Give the outer edge a light grind or sanding to level off any cured balloons and fill-sand any low-high areas, add Three layers of Bi-Directional cloth (aim for a coverage of 450 grams) over the whole of one side, leave half an inch of cloth overhanging the edges, and wrap around the shaft at the leading edge, let this cure.

Flip the rudder over, grind-sand around the edge to line up with the face leaving any of the overlap material that is not too high; fill sand the face of any lows-highs and apply bi-directional as before, let this cure.

Clean up and fair any high-low areas then apply 4 layers of resin wet on tacky, if you allow the resin to cure before getting the next coat on, make sure you wash it with fresh watter and rub with a plastic kitchen scourer till the water no longer forms beads, this will ensure any residue from the curing has been removed and will stop the epoxy flaking, let this cure.

Wash the whole rudder as above and lightly sand, just enough to dull the high gloss finish, apply a coat of epoxy primer and follow this with a good quality paint (2 pot Polyurethane is good), expect no further problems with your rudder.

Avagoodweekend.