Bobstay Question

Idon84 · Post by **Idon84** » Wed Oct 15, 2008 3:24 pm

Hello all!

Got what is probably a dumb question about my new bobstay fitting. The prior fitting was falling apart and in my opinion radically under-built for the job I ask it to do.
http://picasaweb.google.com/Idon84/Cosm ... 5504690690

I have purchased a new fitting to be installed here shortly so I can continue rebuilding the Forpeak. http://picasaweb.google.com/Idon84/Cosm ... 7473292658

My question is this. From the looks of the 2nd linked Picture (uploaded pictures don't show up when I hit preview with the IMG tag above) the part hangs significantly below the water line. I know the part is submerged underway but are there problems associated with it being underwater at rest in a marina (galvanic corrosion etc.)?

Here is the only other Picture I have found of this part showing it sitting significantly higher and out of the water while the boat is at rest. http://picasaweb.google.com/Idon84/Misc ... 9936845250

I know that the more I decrease the angle off the bowsprit I loose strength. I've read that I could remedy this by increasing the bob stay's wire size. Before I drill new holes in the bow where would you put this part? Higher like picture 3 or in the same position as it use to be? Consequences?

BTW, the manufacturer of the part doesn't have any information on the installation. Nor does the new builder of the BCC, as this is a new part.

Have I confused anyone yet?

THANKS!

kendall · Post by **kendall** » Wed Oct 15, 2008 5:03 pm

a gin pole, dolphin knocker or whatever you'd care to call it should allow you to change the effective angles and retain overall strength while moving the bobstay mount up a bit on the bow.

Only realy critical 'mod' would be to provide a suitable mount for the pole.

Ken.

Post by **Tim** » Wed Oct 15, 2008 5:15 pm

I don't see any problem with that hefty bronze piece being submerged--nor would I worry about it in the slightest.

However, given the disparity of mounting locations you indicate, I'd suggest you do what you can to ensure that you install the fitting in the correct place for the bowsprit/bobstay angle as designed. If the higher location is the correct one, then put it there. If the lower location is correct, put it there. I wouldn't necessarily put a lot of stock in where the old fitting was, given that many of the decisions made by the original builder seem to have been poor (hence your complete rebuilding...). But I wouldn't arbitrarily change it without some research into the design first.

A dolphin striker, much like mast spreaders, can effectively allow you to change the angle, but I'm not sure you need to go that route here.

Nice looking part, by the way.

Idon84 wrote:...uploaded pictures don't show up when I hit preview with the IMG tag above...

Note that all image file names must end in ".jpg" or ".gif". The reason your links don't show as images is partly for this reason; you're linking to a Picasaweb page that has your photo on it, not directly to the photo file itself.

To get a proper file name for use in this forum, with the image tags, right-click on the photo you wish to use, select "copy image location", and use that file name here in the forum, as below:

Code: Select all

[img]http://lh5.ggpht.com/Idon84/SNuyVLKRDXI/AAAAAAAABm0/ifC0dxdilzI/s576/IMG_0454.JPG[/img]

This will display thus:

David · Post by **David** » Wed Oct 15, 2008 6:16 pm

What is the size of your bobstay and the size of your forestay?

Personally I don't think the difference in the angle is enough to worry about. Your boat has a very long bowsprit for her size and thus the angle will always be fairly acute. A dolphin striker would ease the angle but would make things more complex. The lower part of the fitting in the water would not be an issue I don't think; although I would be sure to use bronze fasteners.

David

Idon84 · Post by **Idon84** » Wed Oct 15, 2008 8:37 pm

Thanks for the tips, as always!

The Dolphin striker is a GREAT idea for changing the angle but I don't want to change the looks of the BCC, I probably should have mentioned that. I've been reading Brion Toss' rigging book which is where I got my data i.e., angle, increasing wire size to compensate etc..

Fortunately I have many pictures of the part before removing the boat from the water to know where it sits in relation to the waterline as well as other BCC's with the other "past" stainless fittings that were installed. Totally different set up than this "new" bronze part.

The boat in the picture was a custom WOOD built 30' Lyle Hess cutter and not a FG BCC. It just seemed strange why it was installed so high up compared to other BCC's. The guy wasn't very friendly so I didn't get to ask him the question.

I'll put it where the majority of BCC's have it, right at the top of the LWL. 1" higher than in the picture that Tim posted for me. That looks to be the best place for it. I'll work on getting that picture posting down! Thanks Tim for the tip.

David, don't know the size but can find out. And I only intend on using bronze fasteners, but I need to find a good 3/16" backing plate for that narrow area inside the hull. I'll need to measure that too. Any suggestions on that? McMaster-Carr I would guess would be the best place for that?

David · Post by **David** » Thu Oct 16, 2008 9:06 am

Bryon,

I built a new backing plate for my bobstay chainplate as well. I had a disappointing experience with Mcmaster Carr in ordering stainless steel. What they shipped me was carbon steel although they swore it was stainless. I sent it back and they corrected the order by sending more carbon steel. At that point I gave up and ordered stock from metalsDepot.com http://www.metalsdepot.com/index.phtml

FYI: I'm not sure what Toss says on the subject of sizing bobstays, but Richard Henderson in his book on Rigs and Rigging (which I treat as a bible for rigging) says the bobstay should be one size larger than the forestay.

Good luck,

David

Idon84 · Post by **Idon84** » Thu Oct 16, 2008 11:56 am

David,

Thanks for the tip, link and a new book to read. Toss said increasing the bobstay wire is a good idea to help ease the mind as well. Currently all of my rigging is the same size. I do know that.

Thanks all again!

Idon84 · Post by **Idon84** » Thu Oct 16, 2008 12:26 pm

Something else...

Wouldn't it be prudent to use a backing material of the same type? If I've got a bronze part with bronze fastenings, I wouldn't want to use a stainless backing plate?

I noticed David's link doesn't sell bronze. How important is it to have like metals for your backing plates. (I've got a lot of backing plate material to buy as the boat was built with cheesy small washers all over the place).

David · Post by **David** » Thu Oct 16, 2008 12:56 pm

Bronze would be a more traditional and same-metal approach to be sure. However, since you are not getting water past the exterior fitting I see no reason not to use SS if you want. That's what I am doing for my bobstay fitting (bronze with bronze hex head bolts) fastened thru the bow and thru a stainless backing plate: http://bristol29.com/Projects/bowspirt/ ... chainplate_

David

Idon84 · Post by **Idon84** » Thu Oct 16, 2008 2:20 pm

GREAT! It's all ordered.

David · Post by **David** » Wed Nov 05, 2008 9:42 pm

Bryon,

I was looking at the photos of Cosmic Dancer sailing, prior to refit and I see that her ports are upside down from how ports ususally are installed so that they latch at the top. I've never see that before. Is there a story about it?

http://picasaweb.google.com/Idon84/Cosm ... 9391646514

David

Idon84 · Post by **Idon84** » Thu Nov 06, 2008 1:58 pm

David,

You are quite right. They are in upside down. Bought the boat that way and have every intention on installing them correctly next time. They are all currently receiving a light grit sandblasting and polishing.

I am technically the 2nd owner, on paper, but a 3rd party fixed it up and sold it for the 2nd owner who long since passed away. If he didn't remove and reinstall them wrong, which I highly doubt because I spent 4 hours (after breaking 1) gently trying to remove the outer rings from a white substance that was incredibly difficult to get off, then they have been that way since 1980.

There are a couple of crazy things about the boat that make me ask "What were they thinking?" Fortunately none of them are very serious. The hand rails were just screwed to the deck not through bolted as well. Stuff like that.

David · Post by **David** » Thu Nov 06, 2008 4:52 pm

Very interesting. the only ports I know of that open in from the top are on the Cheribini 44 and 48 and originally on Ticondoroga and maybe other Herreshoff boats. I guess each to his own.

Idon84 · Post by **Idon84** » Thu Nov 06, 2008 4:57 pm

Knowing what I know about the boat. My guess is the owner didn't want to have to buy something extra to keep them open!

David · Post by **David** » Thu Nov 06, 2008 5:18 pm

Oh that's funny! Those porthole leases are very expensive :)