How much weight can a halyard and boom hold?

[Letterkenny]

As the title says, how much weight can a main halyard, spinnaker halyard, and the boom (say at the end of it) hold each individually? Is 400 pounds too much?

[44'cruisingcat]

Sorry, the only answer is "it depends."

Halyards can be all kinds of line, sometimes even wire. They can be 2:1 or single. They can be brand new or ancient, UV destroyed.

Our main halyard is12mm Spectra, and 2:1. So theoretically it could take around 10 tonnes when new!

On your boat, if the halyards, sheaves, etc are in good condition, they should take 400lbs easily without breaking.

Really, the halyards ought to be able to comfortably handle the load you can generate with the halyard winch, operated by hand.

[Breaking Waves]

Originally Posted by Letterkenny

As the title says, how much weight can a main halyard, spinnaker halyard, and the boom (say at the end of it) hold each individually? Is 400 pounds too much?

it would depend on the boat, and halyard . . . but on the sort of boats we normally talk about here the max working load would be rather more than 400lbs. - like perhaps 3 to 5 times that. The halyards themselves are usually sized for minimizing stretch and are stronger than necessary for the likely max working loads.

[Reefmagnet]

Halyard and boom is quite commonly used to lift engines in and out of cabins so done right they can bear weight. The trick with the boom is to rig it so any load places it into compression.

[Jammer]

Originally Posted by Letterkenny

As the title says, how much weight can a main halyard, spinnaker halyard, and the boom (say at the end of it) hold each individually? Is 400 pounds too much?

That depends on the boat and the nature of the situation.


Here are breaking strengths for new polyester rope from the two major vendors in North America:


https://www.defender.com/category.js...473&id=2079480


https://www.defender.com/category.js...473&id=3117098


Typical 3/8" line has a breaking strength while new of about 5000 pounds.


Some boats including mine use hybrid rope for halyards, mainly because it has less stretch. But the breaking strength is roughly double:


https://www.defender.com/category.js...774&id=2078783


Whatever kind of line is used, the breaking strength then has to be derated, and it is possible that other components in the system are weaker, such as the blocks, or the mast, or the standing rigging. For loads that do not involve risk of serious injury or loss of life, usually a derating factor of at least 4:1 is applied. For overhead lifting, climbing, etc., a much higher derating factor is used. Most responsible sources will not recommend a specific derating factor because it varies depending on the equipment condition, recency of inspection, types of knots and splices, other safety equipment in use, and so on.


I would not apply a 400 pound load to the halyard on my 12' sailboat.


I would be concerned about applying a 400 pound load to the halyard on my 26' sailboat and would try to find better alternatives.

[Mike OReilly]

What kind of lines? What size/diameter? What kind of blocks & sheaves? What are the tang/connection points?

Certainly size matters. I wouldn't hang 400# off a 1/4" line, but I have hoisted my 1000# mast with my 5/8" jib sheets.

Breaking loads are published for all lines & blocks. I'm sure you can look them up.

[Calif.Ted]

That should be ok on a new 349 but you can't let us die of curiosity, what you got in mind ? Dinghy, or you know someone weighs 400 lbs who wants to stand on the boom ?
And if you want to lift it, depends on you and the winches. A 200+ lb friend wanted 150 lb. me to winch him up once and with the tiny winch on his mast I couldn't get his feet off the ground.

[Letterkenny]

Brand new Jeanneau 349 so not sure what size the rigging but everything new so no concern for wear. The hoisted object now, well that’s simply a hammock for 2 (and maybe a couple kids). Would like to hang on the bow or hanging with the boom over the water and hammock hanging from there.

[George_SD]

Totally fine if you do it right.

[sailorboy1]

Come on. The halyard and boom on 30’+ boat will hold waaaay more than the OPs 400 pounds wants

[Letterkenny]

I mean I figured but I don’t want to hurt the boat! This thing is going to be my baby.

[Jammer]

Originally Posted by sailorboy1

Come on. The halyard and boom on 30’+ boat will hold waaaay more than the OPs 400 pounds wants

The line load as described is considerably greater than 400 pounds.

[Breaking Waves]

The loads on mainsail halyard for a Jeanneau 349 in 25kts of wind would be around 1400lbs (I looked up your rig/boat diminsions and ran them thru load calculator). The system would be designed for some safety factor above that.

[Ninedotsix]

Originally Posted by Letterkenny

Brand new Jeanneau 349 so not sure what size the rigging but everything new so no concern for wear. The hoisted object now, well that’s simply a hammock for 2 (and maybe a couple kids). Would like to hang on the bow or hanging with the boom over the water and hammock hanging from there.

It’s simple to nearly eliminate the bending stress on the boom by taking a lashing around the boom, and suspend the boom by attaching the halyard to the lashing. Then suspend your load, whether the kids or a Diesel engine from the lashing directly below.
This way the boom sees mostly compression thrust to the mast, and little to no bending moment.
The halyard will see slightly more than the dead weight, due to the proportions of angle.
Further caution to be taken if using a end of boom topping lift for this operation.
Cheers
Pete

[TrentePieds]

Letterkenny:

Jammer has already given you a coupla references giving you the strength of ropes. But for such "raw" data to be really useful you really need to understand the fundamentals of rigging. You would do yourself a great favour if you'd devote two or three hours (that's all it will take!) to acquire that understanding.

Here is something to get started with :-):

https://www.energy.gov/sites/prod/fi...ndamentals.pdf

All the best,

TrentePieds