What is correct relative position of mast and boom

[hns1934]

My questlion is should the boom be perpindicular to the mast when fitted properly with the main sail. On my boat, the sail is such that the boom drops below the horizontal by a noticeable amount when the sail is full up.

[artbyjody]

You should have a line called the topping lift, attached to the end of the boom. You use this to raise / lower the end of the boom and that will allow you to control the depth of the boom in conjunction with the vang and main sheet lines...

[Hartley18]

Yes - it should.

Topping lift will get it back up there, but it sounds like your mainsail might have stretched a bit..

[bubb2]

It is the dreaded boom droop, it happens to all the older girls. I mean boats!!!!!

[sailingdog]

Actually, it depends on the boat... some boats have mast rake, and the rake needs to be accounted for when cutting the sails. Some have forward rake, which is a bit rare, but those sails might not leave the boom at a right angle to the mast... However, IMHO, most of the time, the boom is horizontal...

[Delirious]

Boom parallel to the water is normal, even with an aft-raked mast. Is your mast perpendicular to the water? Sometimes the leech gets "tired" and the boom droops. Othertimes someone gets a grand idea and figures it is a way to gain a fraction of a square foot for an advantage in one design. I kid you not - there's even a name for it and I remember a protest filed by one Flying Scot racer against another that it was done deliberately.

I don't miss racing much.

There are also a couple one-designs that have two outhaul grommets to allow this as a mini-reef.

[T34C]

Some booms are designed with a gooseneck that fits into the slot on the mast and can be adjusted up and down. Sometimes these are adjusted and then locked into place and sometimes it is adjusted with a down haul at the gooseneck of the boom. Make sure the boom is in the correct position.

[artbyjody]

Originally Posted by sailingdog

Actually, it depends on the boat... some boats have mast rake, and the rake needs to be accounted for when cutting the sails. Some have forward rake, which is a bit rare, but those sails might not leave the boom at a right angle to the mast... However, IMHO, most of the time, the boom is horizontal...

Dog is right on his points - however about mast rake - some additional info for those reading and you sail not just a cruiser. Unless you have a race oriented boat (which doesn't seem to me you have) - Raking of the mast is more to effect to the genoa / jib and not necessarily the main.

They go hand in hand though...So, even in the race mode of things - there is a balance, and a bigger picture to be had. You can control the main and rake with the backstay. The rake of the mast controls the depth of the main but also the jib and genny. More rake means the the boom will go down to a certain degree but is designed to spill wind in higher winds. Less rake means the main, if the topping lift is adjusted correctly - will mean a tighter main for light winds.

However, rake effects the genny / jib. The main topping lift doesn't effect anything but the main.

When racing or wanting more out of the boat - when raking is desired you should adjust the foot of the genny / jib to give it the proper shape (something not typically done by those that do not play with their sails).

If you have dacron the average I think is 8% a year stretch. A decent sailloft can recut the main and make it more usable... but I think the problem you are describing is that the boom and topping lift. I know on my Baberis - the topping lift was an afterthought and just cleated off at the mast when I bought her.

[sailingdog]

Jody-

My point is that:

If the boat has the mast rake set wrong, the boom may not be parallel to the water or at right angles to the mast.

If the sail has stretched out, the boom may not be parallel to the water or perpendicular to the mast.

If the sail was cut wrong, the boom may not be parallel to the water or perpendicular to the mast.

And that on some boats, the boom and mast aren't going to be perpendicular if the sail is cut properly and the mast is raked properly.

[Sailormann]

What is correct relative position of mast and boom

You usually want to aim to have the mast pointing upwards and the boom pointing backwards.

You're welcome