# Hammock on my 25' sloop?



## kwaltersmi (Aug 14, 2006)

Here's a silly question: Can I hang a hammock from the forestay and mast of my 25 foot sloop? Will the forestay and mast support my 200lbs? I'm assuming they will and that the forces of the wind when sailing far exceed my mass, but I thought I'd ask before I have to post a thread titled "Help! I snapped my mast by installing a hammock!" 

And yes, I'm prepared for the "Why would you want to put a hammock on your boat" posts.


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## timebandit (Sep 18, 2002)

I have a really great hammock in my back yard. I thought I would put it on my 25 foot boat. I took it off the stand and out to the boat I went.

First I tied it to the mast above the boom and then to the top of the pulpit. It looked great but when I got in it "bam" my ass hit the deck. I looked at tieing it higher but the angles said that would not work.

I tried it back over the cockpit. I tied one end on the mast at the same hight as before and the other to the pushpit. It hung about 6 feet above the cockpit, untill, I got in. It then sagged and put the middle of my back on the edge of the house roof.

No Joy.

I am 200# and I did try to run it up the forstay shortening the hammock to the first set of its spreaders.
The stay held the weight ok and that is on a supposed under sized mac stay.

I am still looking for a shorter hammock.

Rick


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## Plumper (Nov 21, 2007)

I hang mine there on a 33' boat all the time.


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## heinzir (Jul 25, 2000)

I use a cheap camper's hammock between the mast and forestay on my 23' boat. Not good for sleeping but great for reading or watching the sunset.

Henry
Chiquita


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## h16Sailor (Mar 7, 2007)

first;
your mast should support a lot more than 200lbs of sail force so your safe weight wise.

second: i found a web site selling hammocks 'sailor's hammock' crusing hammock ? can't find it now but the point is 
they use a three point tie in to make the hammock stable: mast, side stay, and fore stay. they claim you won't get dumped out accidentially using a three point attachment. 

last : What kind of knot do you use to tie your hammock to the forestay?
i plan on trying a double clove hitch, will it work?? What knot will?


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## knothead (Apr 9, 2003)

h16Sailor said:


> first;
> your mast should support a lot more than 200lbs of sail force so your safe weight wise.
> 
> second: i found a web site selling hammocks 'sailor's hammock' crusing hammock ? can't find it now but the point is
> ...


A 25 foot boat is probably going to have 3/16", or thereabouts, wire for the standing rigging. 
A 200" guy pullling on that headstay horizontally is going to induce a lot more stress on the rig than I think you understand. 
I don't doubt that it will handle it but I'm not sure it's a good idea.


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## Plumper (Nov 21, 2007)

The dreaded vector pull. Just don't string the mick up tight and use the jib halyard to hold that end up.


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## TSOJOURNER (Dec 16, 1999)

I thought about putting one up but am too scared on 25' rigging


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## knothead (Apr 9, 2003)

Plumper said:


> The dreaded *vector pull*. Just don't string the mick up tight and use the jib halyard to hold that end up.


Vector pull? 
Please elaborate.


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## JSL3 (Jun 6, 2007)

h16Sailor said:


> first;
> last : What kind of knot do you use to tie your hammock to the forestay?
> i plan on trying a double clove hitch, will it work?? What knot will?


A prussic knot works great on a stay that would support it. The beauty of the prussic is that it slides up easily but won't slide down. On a 25' sloop however, I echo plumper and say use a halyard at one end (near the forestay) and use the mast for the other end.


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## NauticalFishwife (Dec 12, 2007)

We make a loop of line around the forestay (roller furler) Then take the spare halyard and take it inside the loop. Then attach the hammock on the spare halyard and mast. Great place to just hang....


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## knothead (Apr 9, 2003)

NauticalFishwife said:


> We make a loop of line around the forestay (roller furler) Then take the spare halyard and take it inside the loop. Then attach the hammock on the spare halyard and mast. Great place to just hang....


NauticalFishwife,

What diameter wire is your forestay? And what make of furler?


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## kwaltersmi (Aug 14, 2006)

Seems the group is divided, so I'll play it safe and not hang the hammock on the forestay.


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## NauticalFishwife (Dec 12, 2007)

Knothead... tis a Harken furler and I think the forestay is 5/16. This is on a 37 foot boat... but we use to hang a hammock on our 24 foot Cal. But again, we used a spare halyard and took it to the forestay. Maybe we were just lucky? Kwaltersmi, ask your rigger what they think.


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## kwaltersmi (Aug 14, 2006)

NFW - Wish I had a rigger! Hopefully by mid-season I'll know one or two in my area. 

How do you use a spare halyard at the forestay? Is the halyard attached to both the forestay and the hammock? If so, doesn't this induce the same pressure on the forestay that we're trying to avoid? If the halyard isn't attached to the forestay, how do you keep the hammock spread out?

Again, I suppose I'm leaning towards not using my hammock. I'd rather feel good about the condition of my rigging than swing away an afternoon in the hammock.


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## lbdavis (Apr 23, 2007)

kwaltersmi said:


> How do you use a spare halyard at the forestay? Is the halyard attached to both the forestay and the hammock? If so, doesn't this induce the same pressure on the forestay that we're trying to avoid?


I was reading this thread thinking the same thing. I REALLY want a hammock on my boat, but have always feared the forces applied to the stay by the vector pull.

Knothead, a vector pull is a method of gaining mechanical advantage when trying to pull an object:










Here, while trying to pull point A to point B, a second line (vector) may be attached to the middle of the original working line. It's a 2:1 or 3:1 advantage when you pull on the vector line as well, IIRC.

I'm no physicist, but doesn't that mean your 200 lbs is now 400 (2:1) or 600 (3:1) pounds pulling on your masthead?

Someone tell me I'm wrong, I want to look like this this weekend:










- LB


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## SailKing1 (Feb 20, 2002)

I believe someone mentioned earlier in this thread a three point hammock for sailboats. They can be found at Coolnethammocks.com. along with different ideas for setting them up.


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## h16Sailor (Mar 7, 2007)

JSL3
Thanks for the knot information. This knot was new to me.

I tried to find a simple formula to understand the forces I could apply vs. the forces the sail applies. As I think the sail applies much more force than I ever could, why else would I need winches on my boat. I still think me in a hammock is applying less force than pulling on the sail using the mechanical advantage of a winch.
I realize the force is spread out over the jib but, at the point of attachment 'Jib sheet shackle' the force should the greatest. Why is this force applied less than the force of a hammock and me? 
I am ready to be taught where I am wrong. Just keep in mind I am a Psychology major not an engineer.

I found Introduction to statics: Force Resultants

So much for my daily learning. This appears to be an really easy understood equation and it explains why I'm not an engineer.


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## knothead (Apr 9, 2003)

lbdavis said:


> I was reading this thread thinking the same thing. I REALLY want a hammock on my boat, but have always feared the forces applied to the stay by the vector pull.
> 
> Knothead, a vector pull is a method of gaining mechanical advantage when trying to pull an object:
> 
> ...


Thanks LB,
I think it's the same principal as swaying a line. I know that the forces are increased but we'll have to wait for SD or someone a lot smarter than me to tell us how much the increase is.

Again, I'm sure the headstay would handle the weight, I am just concerned that the foil or wire may be damaged.


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## Columbia9_6 (Apr 15, 2006)

Effectively, your vector pull is darn close to the same direction as the pull of the sail... So, it's not a factor. as the drawing shows a perpendicular pull to the longitudinal axis of the wire, you are referring to the shear strength of the wire.

However, by adding gravity into the vectoring, the pull would actually be close to a 45 degree angle. It will pull towards the mast and down.

What you are concerned with is:
- the shear strength of the wire rope, which is way beyond your 200 lbs
- the bend in the wire rope. a radius of twice the diameter would be the maximum bend. for 3/16" wire rope, a bend of less than 3/8" radius would not kink the wire.

All-in-all it's a great idea. I use a nylon double hammock; attached to the mast where the spinnaker pole attaches, and then a bridle to the fore stay. My wife and I have spent many lazy evenings at anchor without a problem.


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## knothead (Apr 9, 2003)

Columbia9_6 said:


> Effectively, your vector pull is darn close to the same direction as the pull of the sail... So, it's not a factor. as the drawing shows a perpendicular pull to the longitudinal axis of the wire, you are referring to the shear strength of the wire.
> 
> However, by adding gravity into the vectoring, the pull would actually be close to a 45 degree angle. It will pull towards the mast and down.
> 
> ...


Sounds like it wouldn't be a problem then. And I guess the fact that so many have done it without any ill effects says it all. 
I do think that I would try to spread the load along the forstay a little though. 
It really doesn't take much to bend the extrusions on some of the smaller furling systems.


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## knothead (Apr 9, 2003)

I asked sailingdog about this and he didn't a problem. 
However he also suggested that you try to distribute the load along the headstay instead of attaching it to one spot.
Thank, SD

Steve


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## Plumper (Nov 21, 2007)

My two cents worth:
The vector pull is most efficient (highest) when the load (hammock) is pulled taught at 90 degrees from the forestay. In the case of slinging a hammock, the pull is far from 90 degrees from the lay of the forestay. The trick to reducing the load is to have lots of catenary in the hammock so the load is more down than out. In order to ensure the requisite catenary, there must be sufficient distance between the two points supporting the ends of the hammock. That is the limiting factor. If the hammock is pulled tight you risk damage.
That being said, I use my hammock on my foredeck often. I sling it quit loose and the forestay barely deflects. I weigh 230.


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## sailingdog (Mar 19, 2006)

The forces generated by the headsail on a boat that size are indeed greater than the "weight" of the hammock and person... but the forces generated by the sail are spread over the length of the forestay, with no point loading. The forces generated by a person sitting in a hammock increase when the hammock starts to swing/sway, as it generally will on a sailboat. My greatest concern would be how the point loading of the forestay damages the stay or foil.  I think it would probably be fine if you spread the load over some length of the stay or foil...but I'm not comfortable with point loading the stay.


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## Plumper (Nov 21, 2007)

Use a bronze hank or an aluminum carabiner for the hammock. It will wear before the SS Forestay.


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## tager (Nov 21, 2008)

Why not just hang it under the boom?


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