Leveling a boat on land

[Sail22Capri22]

I would like to step the mast on my Capri 22 while it’s on the trailer and spend some time on the rigging to set it up and have it some what tuned so I know how to set it up at the ramp before I launch for the season. Anyway, could I assume the mast deck plate is a good surface to put a level on while I adjust the trailer to get the boat in a position it will be while in the water? Mainly need it level because I want to hang a weight from the main halyard to check mast rake and straightness. Also think maybe the cabin floor would be a good spot but harder for me to see the level by myself.

 

[Siamese]

I wouldn't trust the mast plate. Seems like it could easily be off a couple degrees. Ditto for the cabin floor (sole).

The only place I would trust for level is if you have a scum line visible on the hull. Unless you live where the water is crooked, it will be reliable. Then, use a water level. A clear plastic tube that runs from stem to stern with some slack. Fill the plastic tube with water (adding some colorant helps), and you and an assistant can hold one end up to the scum line at the bow, and the other at the stern. The water in the tube will be LEVEL. Adjust the trailer tongue until the water level at each tube end is even with scum line. Done.

If you don't have a visible scum line, you could use the Catalina waterline stripe, although the scum line would be the gold standard.

 

[jssailem]

I raised and lowered the mast on my Montgomery 15 trailer boat all the time when at the house.
Perfectly level is not critical for the task you are contemplating. More important is making sure your boat is on a solid footing and secure. You will be working high and near the edges. You do not want the boat to move or rock while you are busy. I blocked (wedged) the trailer wheels and then adjusted the height with the trailer tongue wheel.

Your mast is what 15-20 feet in the air? You will not have a lot of precision measuring 1º of angle from vertical using a halyard. Nor is it critical to the ability to optimally sail your boat by setting the mast rake to "exactly" 5" aft of vertical. Will you be able to repeat exactly the set up each time you transport the boat to the water, and raise the mast. I strongly doubt it.

You can use relative position. You set the mast up, sighting up the mast for it being as straight as it was lying on the saw horses next to the boat. With the mast on the saw horses you should be able to sight along the mast and identify if it is bent or is true.

With your halyard hanging down along the mast (having determined that when you raised the mast it was pretty much vertical at 90º to the horizontal) measure the distance of the halyard from the mast base. Then adjust to the rigging to set your rake. Measure the length of the halyard from the mast head to the starboard shroud at the rail. Match it to the distance on the port side by tightening or loosing the turnbuckles.

Then go out and sail the boat. Most rigging tuning occurs with the boat in the water not on land.

 

[sesmith]

Level is not a realistic measure on a boat. If you want to be exact, float it. I would wait to measure rake on the water. Side to side you can get by using a halyard to a fixed point when the boat is on the trailer.

If you know the waterline on the boat, you could measure from that to ground and adjust the trailer so front and rear are the same distance to the ground. If the ground is level, then you'd be close to how the boat sits in the water.

 

[NYSail]

Why not just use a laser level to do show the rake in the mast?

 

[Ralph Johnstone]

The only place I would trust for level is if you have a scum line visible on the hull. Unless you live where the water is crooked, it will be reliable.

Both brilliant and hilarious !

 

[NYSail]

I wouldn't trust the mast plate. Seems like it could easily be off a couple degrees. Ditto for the cabin floor (sole).

The only place I would trust for level is if you have a scum line visible on the hull. Unless you live where the water is crooked, it will be reliable. Then, use a water level. A clear plastic tube that runs from stem to stern with some slack. Fill the plastic tube with water (adding some colorant helps), and you and an assistant can hold one end up to the scum line at the bow, and the other at the stern. The water in the tube will be LEVEL. Adjust the trailer tongue until the water level at each tube end is even with scum line. Done.

If you don't have a visible scum line, you could use the Catalina waterline stripe, although the scum line would be the gold standard.

The problem I would see with using the "scum line" is that many boats dont sit level in the water.....

 

[Sail22Capri22]

Thanks for the reply’s. I think I will get it level Best I can. Step the mast, set up the shrouds and tensions/rake just to get an idea of where things should sort of be then fine tune while she is in the water. The boat is new and new to me so I don’t have a routine yet as far as rigging. I am going to tune the rig according to info I found on North Sails and Ullmans tuning guides I found online.

 

[Project_Mayhem]

As soon as you step on, or move about the boat, it will no longer be level. Tires and suspension compress on land and "center of gravity" will shift when it's on water. I would suggest using a laser tape measure that can read angles if you decide to proceed with this task. They're definitely worth the cost

Also be sure to block the back of the trailer. Sailboat trailers often tip upwards when you put weight on the back of the boat. I usually toss a brick or wood block under the frame with an inch or so of clearance. It's not perfect but has been reliably preventing significant tipping over the past six years or so

 

[jssailem]

I would suggest using a laser tape measure that can read angles

Or... since laser light is visible you can use one of those kitty toy pen laser lights and a large protractor (like the one you use to proscribe bearings on your paper charts - dual use tools).

 

[Project_Mayhem]

Or... since laser light is visible you can use one of those kitty toy pen laser lights and a large protractor (like the one you use to proscribe bearings on your paper charts - dual use tools).

Charts? You mean like that ones that dont take batteries?!

If you can use gravity as a "reference" I think it would work. I was trying to avoid referencing a potentially unlevel surface of the boat

 

[jssailem]

If you can use gravity as a "reference" I think it would work. I was trying to avoid referencing a potentially unlevel surface of the boat

I believe the reference point is the boat sitting at rest in the water.
On a still day with no movement about the boat you should be able to zero a level at the mast. If for only long enough to identify the mast is perpendicular to that level point. (Or nearly so) perfection is not needed here.

With that bit of knowledge next using the protractor and kitty laser identify the angle of the mast.

In the simplest approach I grabbed the main halyard and once checking for pretty much (M1 eyeball of the mast at rest) vertical used a ruler to measure the distance from the mast base that the halyard hung.

Then I went sailing. Recorded my performance. Stopped, adjusted the mast angle a few inches. Repeat the sailing. This only took a couple of iterations for competition level sailing to get dialed in. Was helpful when trailering the dinghy from place to place.

Never felt it was waisted activity but not sure it played much in the actual outcome. Back then no one raced with matched boats. More results came from tactics, sails, and understanding of the weather patterns in the event area. Having a light weight boat made a lot of difference.

 

[Project_Mayhem]

I believe the reference point is the boat sitting at rest in the water.
On a still day with no movement about the boat you should be able to zero a level at the mast. If for only long enough to identify the mast is perpendicular to that level point. (Or nearly so) perfection is not needed here.

With that bit of knowledge next using the protractor and kitty laser identify the angle of the mast.

In the simplest approach I grabbed the main halyard and once checking for pretty much (M1 eyeball of the mast at rest) vertical used a ruler to measure the distance from the mast base that the halyard hung.

Then I went sailing. Recorded my performance. Stopped, adjusted the mast angle a few inches. Repeat the sailing. This only took a couple of iterations for competition level sailing to get dialed in. Was helpful when trailering the dinghy from place to place.

Never felt it was waisted activity but not sure it played much in the actual outcome. Back then no one raced with matched boats. More results came from tactics, sails, and understanding of the weather patterns in the event area. Having a light weight boat made a lot of difference.

How much did this adjustment affect weather helm?

 

[jssailem]

My general aproach with boats is to try something and observe how it goes. Record the data and then change and test again.

While there is a correlation between excessive mast rake and weather helm. Weather/Lee helm is in great part a result of hull and mast placement design.

The exceesive mast rake needed to induce weather helm is bad mast placement design.
When racing we were focused on reducing weather helm to nearly neutral. It added a half or more knot to our boat.