How to get a boat "level" when on the hard standing?

[Lakesailor]

The bulkheads will be perpendicular to the water line, so, level the boat using the bulkhead as reference point.

There are lots of assumptions being made about internal joinery having relationship to the trim of the boat when afloat.

All the OP seems to want to do is replicate his mast rake. I have had masts up and down lots when trail-sailing. The best method I found to replicate the rig set up is to wrap the exposed thread on the rigging screws with insulating tape, then slacken the screws off to lower the mast. When stepping the mast again just wind them down until the body touches the tape again. You should be near as dammit back to the same position.
If you remove or replace the standing rigging whilst ashore you need to just start from scratch. If you've had new sails made you will probably need to start from scratch anyway.

 

[rhumlady]

Lakesailors comments above about assumptions is pretty much what I was thinking. The designers may well have done their job and specified bulkheads to be perpendicular and bunk tops to be level but did the builder get it right? Not so certain about that one.

 

[Strathglass]

When I bring my boat ashore each winter on the launching trailer I have to level the boat off as the ground at the sailing club is not flat. I also have to block it up to raise the tyres off the ground.
First I use a spirit level across the bridge deck then I use the spirit level on the cockpit floor to ensure that any water there will run aft to the cockpit drains.

It is possible to set the boat level fore and aft relative to the waterline if there is open access from one side by projecting a horizontal laser line on to the side of the boat. This is quite finniky to set up but can be very useful. I used this method when building the boat to define a straight and correct waterline by ensuring that the projected line ran through the three waterline marks marked on the hull by the manufacturer.

This can only be correct if the waterline on the craft has been marked correctly in the first place.

It is very unusual to find a boat where all the internal bulkheads and other moulded in parts are parallel and symmetrical with each other especially on earlier hand laid up grp hulls. It is a case of finding where the best surface for measuring how horizontal a hull is sitting on that particular craft and then ensuring that the same surface is used every time.
The only real way to check for mast rake, rig symmetry etc is to do it when the craft is floating.

 

[rogerball0]

The internal moulding on my Centaur was out by a mile in both axis'. I found two boats on the hard and measured the scum line around the boat where the water lapped the hull not the antifoul line then measured a couple mates Centaur's in the water to confirm, deviation between all fours boats was no more than 15mm so plotted an average of those measurements vertically down the centre of the transom and down the stem then set a laser down the side of the boat picking up those two marks fore and aft levelling accordingly, this could also be done using a water-filled hose instead of a laser.

https://picasaweb.google.com/110182886418433827802/LaserTechnology?authuser=0&feat=directlink

Edit: Sorry didn't read the question properly, still high on isocyanates from this morning, ignore the WL bit, to get mine level beam-wise i put a level across the companionway and fore and aft ran a six foot level the length of the cockpit. Although that said if you're confident in your waterline marks you could use them for the fore-aft measurement.

Off to breathe fresh air!

 

[Lakesailor]

Yes, if you mark the stem and stern waterline you can pick them up with a laser on a rotating tripod head and get marks all along the hull which is accurate despite and flare or belly in the hull shape. The boat must be level athwartships to do this.

I forgot to mark the levels before stripping a boat, so dipped it back into the lake to regain the marks You must obviously have it loaded as it will be during use.

 

[Concerto]

Sorry I am going to throw a fly into the ointment.

How do you know that the hull will be sitting in exactly the same shape as it is when in the water. Fibreglass boats flex. When in the water they have almost equal water pressure all over the hull to support the water displaced. Once removed from its natural environment the weight is now being taken by the bilge keels and possibly a few chocks. The ends of the boat will now be lower than whilst in the water. This will now put extra tension on the forestay and backstay.

So even managing to level the boat, you cannot be sure that the bow and stern are at the same level as if they are being supported by water. Yes you will be able to get a crude adjustment to the mast rake, but I stress the word crude. You can only set the rake correctly once the boat is back in the water and loaded correctly as if sailing.

 

[rogerball0]

Sorry I am going to throw a fly into the ointment.

How do you know that the hull will be sitting in exactly the same shape as it is when in the water. Fibreglass boats flex. When in the water they have almost equal water pressure all over the hull to support the water displaced. Once removed from its natural environment the weight is now being taken by the bilge keels and possibly a few chocks. The ends of the boat will now be lower than whilst in the water. This will now put extra tension on the forestay and backstay.

So even managing to level the boat, you cannot be sure that the bow and stern are at the same level as if they are being supported by water. Yes you will be able to get a crude adjustment to the mast rake, but I stress the word crude. You can only set the rake correctly once the boat is back in the water and loaded correctly as if sailing.

thats why i measured scum line left by water on the ones on dry land and a couple in the water , i took measurements either side opposite cap shrouds and there was no difference in numbers. You could be onto something regarding racing boats but for the average cruiser wouldn't have thought it would make alot of difference.

 

[mickywillis]

Thanks to all who replied.
Mast is currently down and laid alongside.
Will be having all new standing rigging prior to mast being stepped.
So just trying to get a basic indication on mast rake and then adjust on water. Not sure if waterline/boot top is in correct position as boat not been in water for a while, so cannot guarantee its validity to use for set up.

 

[Merlin38]

Use a length of clear hose as long as your waterline, secure the ends and fill it up with water. As long as you have an initial reference point for your waterline the level in the pipe allows you to check lengthways and side to side to ensure everything is at the same level as the reference point.

 

[Jamesuk]

Hose pipe 'where does the water go and a
Level