Rudder Alignment

[Keith Bartlett]

"Freddie" sustained a mighty thwack on the rear quarter and the port rudder last Sunday- the D 18 that hit me (he was on Port) demolished 18 inches of its port bow. My damage initially appeared to be "just" the loss of the nylon sliders in the tiller arm, and their attached stainless steel tube. So the tiller arm must have flexed a large amount, as these components can only be fitted by removing the pivot arm at the end of the tiller arm. So that's the background- the question is, now that I have fitted new parts from Windsport, how do I know that the rudders are properly aligned ? I have read George Carters excellent piece on Turbocharging your 15. However there are a couple of questions I need some help on:-
Am i correct that the rudder blades should be vertical when they are in the down position? (assuming the boat is level across the beam)
How can I correct an out of vertical alignment- or do I need to buy a new rudder stock?
Thanks for any advice..

Keith

FREDDIE 1962

[Charles]

Keith

The rudders should be exactly in line with the hull, so as the hulls aren't handed, yes the rudders should be vertical.

[Steve Willis]

If your rudders will sit down with the boat on a trailer then you can do some measurements. For now assume that the starboard one is OK.

Set the rudders in line with the con bar on and tape the conbar or tiller to hold them steady. Then get someone to help measure between the bottom tips of the rudders and then at the top back edge and you should get the same measurement. I use a length of 2x1 instead of a tape measure - put a pen mark a couple of inches from one end on the wood and line it up with one blade and then make a mark where the other rudder blade touches the wood. (You can also use the same measurement along the skegs to see if the hulls are in line - I found mine 'toed in' at the front by 20mm due to wear on the front beam underneathe pads)

Keith,

Also check that your pintle pins are vertical - use a spirit level from the bottom pin up to the centre of the top eye. Have a good look at the bottom pin on the hull and the top one on the rudder and make sure they are straight as they do bend - sometimes 's' shaped.

Check for crazing or cracks of the gelcoat around the hull fittings as they can get damaged (and let water in).

If the rollers came out of the rudder then check the top and bottom castings where they fit to the A frame. Whilst they are castings sideways force can twist the top one so that the bottom of the blade gap is wider than the top - this can usually be seen by looking at the rudder frame from the open end of the top casting - the 'wings' of the casting should be horizontal and in line. If twisted then they will not look in line.

If it has twisted open the rollers will have a tendency to fall out. You can solve it by drilling out the six rivets holding the casting on the a frame and put one wing of the casting in a vice and use stillsons or mole grips to bend the errant wings in line. You may have to flatten off the top of the a frame as well. Monel rivets required to refit.

I made up a wooden table that a 15 or an 18 bare boat can sit on with rudders fitted to check hull and rudder alignment and its now down at our club. If you want to talk it through at all then e-mail me via ssc at ehvpa dot co m (if you know what I mean) with your landline.

Steve

[Keith Bartlett]

Thanks for the advice and comments Steve and Charles. I'm going down to the club this morning, armed with straight edges, and measuring tapes.
I am also going to try another set of rudders, (borrowed from a similar age boat) , to see what the differences are. Watch this space.

cheers

Keith

[Keith Bartlett]

The saga of the rudder alignement continues....... The conclusions from yesterdays measuring session were that the port rudder,( which took all the impact) is vertical and tracks straight, the starboard rudder is tilted out of the vertical by approx 16-18mm. Further examination suggests that the bottom pintle is approx 3mm off from the centreline of the boat, and with the magnifying effect (approx 5 times) of the rudder length, this seems to account for the 16-18mm tilt. The top pintle is dead in line, so we are pretty certain that its the bottom one that is causing the problem. So it may not have been the crunch at all ,and its been like this since new.

So before I start redrilling holes, has anyone got any thoughts? We took the pintle off yesterday, and the holes in the transom are round with no sign of any movement whatsoever.

Steve- your suggestion of using a lenght of 2x1 timber was most useful.

Cheers

Keith

[Steve Willis]

Before you go too far with rudder adjustment think it through carefully as you may next be into con bar length adjustment.

I thought one of my rudders was out on the bottom pin but it turned out it was actually the top pin holder on the hull. When I undid the top plate the holes had elongated sideways so that each had a horizontal slot of about 3-4mm greater than the bolts. Although the bolts were done up tight the plate was in the wrong place. I fibreglassed the holes, gelcoated and then redrilled. As you appreciate 1-2mm at the top fitting is a lot more at the bottom.

Are you sure the bottom pintle pin on the starboard side is straight and vertical, if not it will throw the rudder out even if the casting is mounted correctly. While you are checking what is the condition of the pintle pin casting around the base of the pin - as the rudder sits on this bottom casting the alloy wears away in the middle (striaght ahead position) and not in the wearing positions with 'turn' applied. This leads to the rudder cocking over when you make a turn. As my pintle pins had been bent and there was about 2-3mm wear in the central position I changed them. In fact I ended up changing 4 or our 6 pintle castings due to bend and wear.

The main resason I built the boat table was so that I could sit the boat on its beams dead level sideways and fore-aft and look along the whole skeg line and the rudder blade and check they were in line. I did it each side (making sure the pintle castings on the hull and the rudder blade were also vertical) with the can bar off and then measured the distance across the rudder con bar pins. As I had previously changed my con bar from the old long pins to the later short pin ends with the rudders in the wrong alignment I ended up having to shorten the con bar by several mm.

I have got a number of photos of the boat on the table and the state of the castings/pins which I can e-mail you if you want.

[Steve Willis]

Just a tip when I did the hull relaignment I mentioned the other day and found the bows toed in due to wear on the hull and stops where they rub under the front beam.

Rather than change the stops and rebuild up the hull indentation I glued a 3mm thick rectangle of hard neoprene onto each stop. That 6mm total aligned the bows from 20mm toe in and the neoprene stops the shock and wear.

[Charles]

Keith

Well if your rudder allignment has been out all this time you'll be flying as soon as you've sorted it!

"Watch my transom" will be your new catch phrase!

[Mark Aldridge]

Keith

Listening to Brian talk about rudders on the training course, I suggest you seek professional advice or take a look at the castings. The bottom casting if hit hard enough (and it sound like that one's a yes) can bend and until you replace it (it's a casting so won't bend back) you'll never be the same again.

Glad to hear you're OK..

[Charles]

Hmmm better check mine, I wallopped both rudders on a submerged wall when giving visitors a joy-ride at our open day! I've also got to put 1/4" back onto the bottom of the rudders!! On the upside they drain quite quickly now !!!

[Keith Bartlett]

Thanks guys for all the advice- there is much to ponder. I am hoping to try sailing Freddie this Sunday, when a good wind is forecast, so I can try and judge how she sails before making any changes.

I have come to the conclusion that any re-alignment of the pintles is a job to be done at home, in the garage, under controlled conditions, as I dont want to mess it up. So this is probably going to get done before I go to the Nationals.

There is still something "wrong" with the rudder that sustained the hit- as raising the tiller arm to actuate the locking mechanism is now very stiff and jerky, so I think Mark may well be right that the casting has been knocked out of alignement. I'm going to call Brian and ask his advice.

Cheers

Keith

[Steve Willis]

There are obviously some 'anomalies' and remaining repairs required.

I too think you would be best to talk to Brian P and/or Steve S AND don't rush into a fixit job at the club.

When I was sorting mine out it was at the time of the Dinghy Show a couple of years ago and I spent some time talking to Brian there - after spending 2-3 days checking the boat and rudder measurements (with both our 15s side by side at home) and before embarking on remedial works.

Not only do the verticals and parallel alignment matter but rudder rake comes into it - the shape of both the A frame and the castings is very important and the presence/absence of the buffer at the bottom of the A frame in which the blade sits.

[Robert]

Hope you have the other guy's insurance details, Keith - rudder work might be a bit pricy if the wrong bits are bent. Good luck.

[Neil Parkhurst]

Sorry to be a bit slow but excatly same happended to me but by a rs200. All you need is a Terry Postlewhaite and it can be fixed, cheers Terry