Anyone know how the boatbuilders get the centreboard and rudder aligned and vertical?
I've always used tape measures, lots of care and attention, and mk 1 eyeball. Rudder of course just has to be in line with the board, so turn the boat upside down: simple enough. Locating the plate case can be quite a can of worms, because boats - especially if one is rebuilding an oldie, are very rarely absolutely symmettrical and it may be necessary to compromise. I figure the relationship with the mast is probably the key one.
Thanks Jim, was thinking along the lines of a string line from stem to transom, setting up level side to side on the thwart (upside down) and dropping a plumb line down the transom from the keel to the transom top.
The question is - How will you tell if they are not aligned? The answer is by looking at them. use the same technique to align everything. I take the centreboard out and replace it in the box the otherway out with the boat sat on the trolley. I then line the rudder up with this. I initially stick the pintles on with double sided tape. Once in place i then carefully drill, taking time to check things as i go. Measure three times, drill once....
Thanks for the good advice 'eyes' - I acknowledge the idea of a visual alignment check (or backed up with string lines) - the problem I was struggling with was getting the relevant bits arranged for comparison - the idea of putting the centreboard in from outside hadn't occured to me to set the mast / vertical 'datum' - thanks for that. Once that is set, the comparison with c/b and rudder is more reliable.
If you are turning the boat upside down why not set it on carpeted trestle - a couple of workmates eg. and then push the centreboard up from underneath. Then you will have the precise alignment of the board as it will be when it's in the water. Get the rudder alignment from that.
Laurie Smart builds the case into the hull jig, so he can guarantee that the case is vertical in the boat. Unless the builder of your boat can tell you he did likewise I would certainly not assume that the case is vertical - and I would definitely not assume that the thwart is horizontal!
The case is the first bit of the boat to be built. Everything else is built around that, as Keith points out, to guarantee vertical alignment, etc,etc.
Andy Hay - 3626 Business as Usual
There was a photo sequence in a recent magazine showing the Winder build method. This showed that the case went into the hull moulding at skin stage on the plastic boats. That way it is structurally part of the hull skin. The case capping is part of the internal moulding that includes the bow tank.
I would have thought it very unusual for any Merlin to have foil alignment problems, as they are generally built so well as the boat builders reputation hang on their craftsmanship. If the boat is very old, I can imagine you would have doubts.
What colour are your toe straps Tim, that they clash so badly with your buyancy bag straps, and who chose them in the first place? LOL
Here are some snaps of me doing this on my 12 ... maybe useful
err..the bag straps are red..and the padded toes straps grey..the yellow bags are a colour clash disaster
Thanks for sharing the pictures Rick - thorough job and as they say, a picture is worth a thousand words.
I knew I needed a garage - now I know why!
One one occasion when I was taking Heaven Sent to Laurie's shed he had Luka, the retro Passing Cloud in being redecked etc for Mike Stephens. Several things were not in line and the shroud attachments were not in the same place. He was using the string down the centreline method to align everything. I have previously described a simple way of determining if your mast is perpendicular to the side decks. Cleat your main halyard at the point you can just touch one side deck by the shroud attachment with the end of the rope. Go round to the other side and see if you can do the same. Adjust shrouds till this is achieved. If you do this and then check the C/B by eye you will not be far out.
Provided your older hull isn't twisted then the halyard method works well!!
> I have previously described a simple way of determining if your mast is perpendicular to the side decks.
Oh yes, a laser level is a dead handy bit of kit for these alignment games...
Ask yourself these question, do I keep the boat upright all the time, the answer will be no, so does it matter if the mast is a bit off? What is vitally important and in so many wooden boats that were not built with the case in the mould the answer is no. is is the plate case in line fore and aft. Thats the big one.