Need advice on my rigging

[djn]

Hi All, when my boat was first launched in 1958, the mainsheet connected to the square hoop at the end of the boom pictured here, then down to the middle of the cockpit. In 1974 when the boat was rebuilt, the PO installed a cabin top traveler and attached the mainsheet to three pullies attached to the boom as seen in the second picture. The three pullies are attached to rings that are wood-screwed into the boom with two screws each. My question is, will those wood screws hold if I really start putting pressure on them. The PO never raced the boat and always sailed in mild weather so they have not really been tested. Cheers.


http://i9.photobucket.com/albums/a60/djnagle/Shady%20Lady/HPIM0376.jpg


http://i9.photobucket.com/albums/a60/djnagle/Shady%20Lady/sailing8.jpg

[Joe ( Cold Spring on Hudson )]

Is the running rigging still functioning in the center of the cockpit ?
Do you have a photo of that?

FWIW that mess on the coach house looks like crap. :rolleyes:

[JimD]

How big are the screws and what are they made of?

[mike hanyi]

why not pull them out and see how long they are?

what i see is 3 points (blocks) to 6 screws holding the boom.

odds are it will hold just fine but if you are in doubt why not make better holdingss on the boom like straps simmilar to the one in back, or a rope around the boom at each point saving weight and height.

mike

[djn]

Joe, no, the origanl setup in the cockpit is long gone and the PO did not have any pics.

Jim, I will pull one to find out. They are SS.

Mike, I am going to a friends shop Saturday for a party but I think I will go a couple hours early and make up three straps like the one near the end of the boom. That one is bolt-through and having three of them for attach points would be over-strong.....find by me. Cheers.

[Hwyl]

Joe, no, the origanl setup in the cockpit is long gone and the PO did not have any pics.

Jim, I will pull one to find out. They are SS.

Mike, I am going to a friends shop Saturday for a party but I think I will go a couple hours early and make up three straps like the one near the end of the boom. That one is bolt-through and having three of them for attach points would be over-strong.....find by me. Cheers.

That's the way to go, so the screws are in shear. The straps may be commercially available. I disagree completely with Joe. The new set up is a huge improvement, the boat looks great.

[Ed Burnett]

I would be inclined to have a little more than six woodscrews in that application, however I have to say a larger concern may be with the boom itself.

The sheeting point has moved a long way forward and any sort of leech tension is going to have the boom looking like a banana. At best this makes controlling the upper part of the main difficult, at worst the spar might fail.

If you have a copy of Skenes, there is a pretty good boom dimension chart based on main sail area. If your boom is generous on this yardstick it may be ok, if it isn't I would suggest you make some careful observations in a bit of breeze before hauling too hard on the sheet.

[Figment]

Wow. Where do these Previous Owners come from? And where do they go afterward?

I don't care if the screws turn out to be 5" long, that setup is one careless gybe away from total disaster. Yes please go with some proper bails asap.

What's up with the traveler that appears to be not rigged as a traveler?

[rbgarr]

If it were my boat I'd only feel safe if there were bolts or rod with peened ends through the boom between the (to be installed) strap ends. Is the boom hollow? That would also make a difference in the holding power of any screws.

[Joe ( Cold Spring on Hudson )]

I disagree completely with Joe. The new set up is a huge improvement, the boat looks great.

Ya know Gareth I'm starting to sense a slight difference in our nautical esectics. ;)

I prefer comfy fat, yet graceful boats with clean lines and rigging

Like this

http://i107.photobucket.com/albums/m320/fosterhere/Tidbit/IMG_0980.jpg

While you would prefer the boat in the background it's modern faster ( nice boat by the way) and rigging like this.

http://img.photobucket.com/albums/v251/joserouse/Sailing/Spaghetti.jpg

:D

[djn]

Good one Joe, that 2nd pic is still making me laugh. My boat has a tight cockpit to begin with and having the mainsheet anchor in the center of it, makes it worse.

Figment, The boom is hollow so there is only one inch of wood holding the screws. That traveler is old style with set-screw looking end. The set screws are tightened with a winch handle. When trying to adjust it while sailing, it becomes a finger sheer. I am saving my pennies for control ends to convert it to line controlled. "that setup is one careless gybe away from total disaster"......that is my concern exactly. I will be racing in the boat next season and can't afford to go hog wild with updates but want to focus on the stuff that could kill the crew or boat or both.

Ed, you said "If you have a copy of Skenes", what is that? Cheers.

[djn]

Ed, I found it on line....Skene's Elements of Yacht Design, 8th Edition

My wife works at Border's Books and I'll have her get a copy. Cheers.

[Nanoose]

hehehehehehehe :D :D :D

Thanks, Joe :)

[Ed Burnett]

That's the one. It's a very useful reference to have on the shelf.

The chart in there gives a good starting point for boom design, but with a sheeting point as far forward as yours I would want the boom section to be somewhat deeper than Skene's would suggest.

[mike hanyi]

that picture makes me think of a fake webster description we made up- spaghetti kettle!

now I got a simple idea for the boom, buy threaded rod and achorne nuts, drill them right thru, countersink a bit on top with a regular nut, and achorns on the bottom, make sure to bung and seal the tops not to take rain, but they will be under the track and unseen so there is no varnish touchups to do

[djn]

test

[Ian McColgin]

The 'new' arrangement looks pretty smart. If the aftmost block on the boom can be moved back till it just clears the dodger, so much the better.

Take a sail on a hard day and look at the boom bend. If it happens really badly before you should be reefing anyway, then you may want to make one block at the end of the boom - block with becket on the boom, block on a traveler or center block behind the helm, through block at the end of the boom, then forward to something like your current rig minus one block.

G'luck

[JimJ]

The position where the bolt passes through the boom at the previous position of the mainsheet block on would most likely be solid. I would not like just six ss screws holding the setup as it is now.

[Milo Christensen]

http://i9.photobucket.com/albums/a60/djnagle/Shady%20Lady/sailing8.jpg


Use bails through bolted to match the original bail.
Spread the three new bails such that the middle block is directly above the traveller and the aft most block is as far back as possible and still clear the dodger when up.
You should be concerned, somewhat, about the forward forces on the traveller as well as the concentrated forces on the boom.
The screws got to go!

[Dan McCosh]

I don't think the single bail is original either. The boom probably had a band that distributed the load of the bail. The new setup would distribute the load over three attachment points, but would tend to want to pull the screws out. Three bails similar to the original would be preferable, IMO.

[djn]

So if I move the aft block as far back as possible, do I have to match that distance with the forward block....assuming the middle block is directly above the traveler? I looked at the boat last night and found all the original bracing for the cockpit mainsheet still there but covered by new decking. I thing I will make all these changes as well as install a flush attach point in the cockpit deck for racing. This current setup makes it much easier for crusing but still looks chinsy. Thanks for all your input. Cheers.

[JimD]

I bet there's a smart person out there who understands all this but is this what you're getting at?:

http://static.howstuffworks.com/gif/bt4.gif


http://www.blockdivision.com/images/stress_formula.jpg

[djn]

Thanks Jim. Interesting that at 120 degrees the factor is 1. I think that 120 degrees might be too wide, I will be able to do better than my rig is set up now. Cheers.

[Ed Burnett]

If you actually want to have a look at the loads, there is a handy little formula here: http://www.mauriprosailing.com/Harken/harken-loading-formulas.htm (about half way down the page).

This is courtesy of Harken and usually gives a pretty conservative (large) estimate for traditional boats where you won't be pulling things in quite that hard.

Another way of looking at it would be to consider the winch size and tackle. Say you have a size 28 winch (indicating a 28:1 power ratio), and you assume that a normal person will comfortably apply about 10kg (22lbs) to the handle, that results in something like 280kg (616lbs) of tension in the rope. Over a five part tackle (such as yours) this means a normal person can impose a total load pulling down in the middle of the boom (and up on the traveller) of 1400kg (3080lbs). If that is the working load you would want to apply a factor of safety of say 3 to be reasonably confident that the setup will be able to deal with any eventuality.

You can of course adjust the numbers for winch size or person power (I don't know if you even have a winch!), but this gives you a realistic idea of the load because you know from your experience of the boat how hard you have to pull on the sheet.

You can do as many sums as you like with this sort of thing depending on how interested you are. Apply a bit of beam theory to look at the bending moments in the boom and get another input for considering whether it is strong enough. Like all these things, a few calcs can back up observations and help you get an idea of what might happen on a breezy day. It also gives you the ability to asses the likely affect of any changes - ie you can work out how much of a difference it will make if you move the sheet aft a bit.

Anyway, have a play with the numbers if you are into that sort of thing - otherwise just go sailing and have a look along the boom when you are on the wind!

[dpincus]

Hey there,

not to change the topic, but have you considered adding a turtle hatch to your boat? It's a fixed hatch cover that encapsulates your sliding hatch to let no water in under the sliding hatch (aka hatch house or garage). I think one would look great on your boat especially tied in to your traveller, which I do think looks great.

http://www.woodenboatvb.com/vbulletin/upload/showthread.php?t=49664

btw I think 3 bails is also the way to go. You'll only know if you have enough stiffness in your boom by experimentation. Go and sail in blustery conditions!
Dave