Why do mainsails have booms

[Panope]

Back when Panope was rigged as a schooner, her FORE SAIL (the middle working sail) was boomless. We never adjusted the sheeting angle (no track). The sail was easily reefed. The arrangement worked very well for us.

I reckon that because this sail was gaff headed, the need for a pole (when running) was reduced as the gaff (being a pole) tended to spread the sail outboard automatically.

[El Pinguino]

My Drascombe Lugger ( a 19 foot yawl) has no booms.....
Sistership photo demonstrates the principal quite well..plenty more photos out there...
https://baltimoreyachtcharters.com/i...e_lugger01.jpg
Same same your jib it requires the mainsheet to be lead well aft so the 'extended line' bisects the luff.....

A decent sail area in the lugger is achieved by having a mizzen mast and a bumkin.

Modern yacht design does not favour this rig and in the larger sizes you can't pole out the main when sailing downhill... I use a boathook ...pointy end to the clew... other end wedged against the centreboard case.... works good.

[copaco]

I read over fast but I was just looking over a Nonsuch, with wishbone on a catboat.Inspired by sail board?Quite an inovation!

[billburr]

So you can attach the preventer. 😄

[Suijin]

Originally Posted by Sailor647

Try not to over-think this stuff. There have been hundreds of thousands, if not millions of people who have come before you in the sailing life. Try to trust in their experience and invention and know that if there was a better way, it might have been thought of and executed by now.

I think this is terrible advice.

Beyond innovation, understanding the systems one your boat, how they function, and why they are designed the way that they are is an integral part of gaining seamanship experience.

I trust my Universal M50 is well designed but that has not kept me from becoming adept at understanding it's function, maintenance, and repair. And that approach has served me well on any number of occasions.

[boatman61]

James Wharrams Gaff Wingsails do not have booms.. they rely on a hull to hull traveller to maintain downwind sail shape.. a very effective and powerful sail.

[vpbarkley]

Yes, but a more important question, where did the name boom come from.

The answer: it's actually BOOM, the sound when it smacks you in the head.

Sorry, somebody had to say it.

[clakiep]

Originally Posted by billburr

So you can attach the preventer. 😄

A mainsail with no boom will have much higher forces on the mainsheet. So You will need a reduction on or a winch for the mainsheet as big as for a jib same size. The Wharram wingsails are excellent on a wide catamaran, but have this little disadvantage.

Capt. Claus - ocean tramp of the eighties

[roland stockham]

Simple answer is 'they don't. Mains can be boom-less and head sails can have booms. Sails can be configured in lots of ways. 'Google fisherman's' sail, its an upside down head sail set behind the foremast. Or sprit-sail, no boom on the foot of the main but they have one running from the deck to the outside corner of a 4 sided sail. The important thing is to know how to get the best out of your particular rig.

[Clivevon]

Hi. Welcome to sailing. I dont mean to be rude but i suggest you First use your energy to learn about what is, before asking too many questions about what might be...

[Clivevon]

And forget the books at this stage. Go sailing. On the water...

[Djarraluda]

Different rigs are available, some without a boom, but the Bermuda. Rig was developed and is more efficient.
Alternatives do include those with a loose footed main, see the Drascombe range of small open boats, right up to the 100 foot plus of the Thames Barge, which has a Spritsail rig. Spritsails on the big boats fuel up to the Sprit, and a 120ft boat was sailed by one man,, a boy and a dog. I have also seen an old gaffer without a boom, but no ideas if that was the original design.
In modern boats, most adopt the Bermudian rig which typically includes a boom, simply for the simplicity and performance combined.
Roger

[thinwater]

Originally Posted by Sailor647

Because they do...Try not to over-think this stuff....

Keep learning. You'll love this life!

First you tell him not to ask questions. Then you tell him to keep learning. Funny. And spoken like a non-engineer/tinkerer.


The obvious answer is to look at how the jib sheets are run and how badly most jibs are shaped off the wind. You just can't make it work with a monohull beam, and even multihulls don't want to for other reasons.

[MikeDofFreo]

The primary purpose of the main boom is to protect the foot of the sail from the crews' heads.

[Siberian Sea]

No boom ? How could I possibly place a tarp over my cabin to provide shade in hot tropical anchorage’s ?