Bowsprit end hardware - cranse iron

[allene]

I want to point out that most bow sprits that are added to boats these days and as I understand it the pre-made ones quoted, are for downwind sailing. Some will not even allow a Code-0 sail. A downwind sail puts much less load on the bowsprit than what you would have if you have a forestay on the bowsprit and an upwind sail.

I would be very surprised if you could take the loads of a forestay and an upwind sail without a bobstay and perhaps even side stays. Find an expert before deciding it is good enough based on what someone did for a downwind sail.

Allen
L-36.com

[mauro.iachelli]

Hi All,

Stumble....I understand your point, but I have to admit I tend to agree with Allen. The bowsprits you are talking about are built to set light sails for downwing sailing and are not considered to be used in strong winds and close hauled. I wouldn't consider it safe to add that kind of bowsprit and and no rigging to it.

Allene.... I'll certainly go for a more traditional rig.

CAM... while I keep my opinion on the better windward capabilities of this type of rig (owners of Whitby 42 that made the same modifications are agreeing with me) I certainly find your avices very solid and worth noting. My bowsprit will have a diameter of 120mmm (a little less than 5") and a wall thickness of 12mm (1/2") which I think it will be enough to make extra solid. Do you think it will be too heavy? I wouldn't like to have a carbon bowsprit that would be as heavy as a wooden one....
Other thought could be given to the SS hardware, I agree on the problem and that's why I was thinking of an outer layer of about 3mm (3/16") of fbg/epoxy to defend it from possible hit and metal cuts. Don't you think it would be enough?

I don't know anything about alternative options for fittings of a carbon, can you give me any advices where to study some? Website?
Thanks a lot to all.

Mauro

[CAM]

https://picasaweb.google.com/m/viewe...75016574624786

Pics of the 40'ers sprit the day we bolted it on. That's not the finished bobstay, just some line to hold it firmly in place. I think if you scroll through the pics you can see how it was made. They successfully raced the boat to Hawaii that summer, so it's gone that far at least.

Here's the drawing:

http://4.bp.blogspot.com/_5HeG270aMb...00/40Sprit.JPG

Note I'm not a pro, this was done for some friends I race with. I crunched numbers to the best of my ability, and had access to another NA-drawn plan to refer to and validate my figures. I present it just for your information, not to solicit work, nor would I guarantee this design would work for you.

Your fg covering will add abrasion resistance for sure, probably something more important for a cruising boat that deals with anchor chain regularly. If you could cast the metal part into the sprit, maybe you could get 100% contact. The problem as I see it is the steel will still be assymmetrically loaded, with the bobstay trying hard to pull the bottom aft. Since carbon doesn't give much before failure, the sprit doesn't dent and distribute the point load away from the point of contact. Maybe the glass will address this, I don't know. I do know soft attachments are easier to keep from slicing the carbon though.

[Stumble]

Again, take a look at the sparcraft pole (the one I am adding), it has a factory option to add a bobstay that allows for the use of a code zero. This is a $100 part but of course you also have to add a toggle to the bow of the boat. Which is a pretty easy addon.

These things are not a panacea since they have a limited projection, but within their design limitations they are pretty simple additions, and work quite well.

[Olinelooo]

Consider making the aft end a lot wider than the tip to avoid needing side stays (if attaching directly to the bow). Also consider an internal end fitting (machined aluminum, or fabricated G10) to receive the bobstay and possibly tack lines if you ever fly an asymmetric kite. Can be as simple as a tight-fitting glued-in "slug" with a vertical-cut slot to ring hitch the bobstay and strops through.????