Pressure of rode on bobstay?

[dstrout]

I'm having a problem and am open to suggestions. No matter how I rig the anchor rode, I cannot get it to not push on the bobstay as the boat swings back-and-forth.

I've tried a snubber running over the bow roller, I've tried a very long bridle running from the hawse pipe on each side, I've tried a short bridle. All of them end up pushing against the bobstay.

I'm not worried about chafe - that's solvable. I'm worried about the pressure damaging the rigging. Is it something I should worry about, or is it a non-issue? Don't think 20-30 is going to hurt anything, but I'd like to figure it out so I know what to do when it's 50-60.

thanks,
Dave.

[groundtackle]

dstrout, understand your concerns and its not comfy to watch that conflict.
Have you entertained a single snubber attatched to the lower bobstay waterline fitting.
ce

[senormechanico]

groundtackle has it exactly right.
Most bobstay lower fittings have an extra hole for a shackle.
Attach a single three strand line to the shackle from that and run it up to the deck.
A snubber in that line is also a good idea.
Attach a chain hook on the business end.
This will greatly reduce swinging at anchor as well.

[Cheechako]

I wouldn't worry about the pressure on the bobstay. Chafe is another thing though. You are saying a snubber led thru roller still rubs on the bobstay... How does that happen? ....you mean due to current or reversing winds? I guess your rollers must be well back from the end of the bowsprit..?

[dstrout]

That's brilliant and would never have occurred to me - I shall give that a try. Thank you both!

[dstrout]

Actually, let me ask a follow-up question. Is this even an issue? Do I risk damaging the bobstay from the side pressure? Or am I solving a non-problem?


thanks,
Dave.

[barnakiel]

This is a bobstay design fault.

Where anchoring is foreseen, the bobstay ends above the water line and en eye fitting is set below it, closer to the waterline. Now your painter/snubber passes thru this fitting.

When designed and built like this, the rode never brushes the bobstay and the boat sails at anchor much less.

If you are already left with the stupid set-up, then you can try and wrap the lover part of the bobstay with a soft material. This hopefully minimises the noise.

I am in the same box too ;-(. I can't say we ever suffered any damage much as the chain did press on the bobstay quite a bit at times. How much pressure depends on the whole kit and on where you attach the snubber.

Take heart ;-) and improve your design, if you can.

Cheers,
b.

[senormechanico]

Originally Posted by dstrout

Actually, let me ask a follow-up question. Is this even an issue? Do I risk damaging the bobstay from the side pressure? Or am I solving a non-problem?


thanks,
Dave.

When we purchased our previous boat a Lord Nelson 35, the broker mentioned that the bobstay fitting was a very strong point and the extra hole in the fitting was for that very purpose.
It was designed to take full anchor loads even in a hurricane.

On one occasion when anchored in Melaque, Mexico on a day with a LOT of surge, the 3/4" three strand anchor snubber let go when it parted in the increasing huge swell.
It had a rubber dock line shock absorber with three turns of the line on it which helped, but the swell ate it anyway.
There was a huge bang when it parted.

The next day, I took a look at the bobstay fitting.
If it had been able to speak, it would have said, "What? Me worry?"

One more thing I did to fine tune this setup, I used SS washers on each side of the bobstay fitting so the shackle couldn't move sideways producing a click each time the boat swung slightly.

AHH !! QUIET at anchor !

[dstrout]

Originally Posted by Cheechako

I wouldn't worry about the pressure on the bobstay. Chafe is another thing though. You are saying a snubber led thru roller still rubs on the bobstay... How does that happen? ....you mean due to current or reversing winds? I guess your rollers must be well back from the end of the bowsprit..?

Correct - The rollers are in a platform that sits in the bowsprit and are probably 2' behind where the bobstay attaches to the bowsprit.

What I have been doing is running a piece of three-strand with a chain hook over the roller from the samson post. I have a piece of fire hose on the three-strand where it contacts the bobstay. Once this has taken up the tension from the rode, I let some more chain out so that a little excess chain hangs straight down out of the way.

I do that so that the rode (I run all-chain) doesn't chafe against the bobstay, but the three-strand is still pushing against it.

Does that make sense?

[dstrout]

Originally Posted by barnakiel

This is a bobstay design fault.

snip

Cheers,
b.

It can't be a design fault. It's a Bob Perry boat - they are faultless!

I just looked, and I can't quite tell for sure if there is a place to put a shackle on the lower fitting. I know there isn't a separate loop. I'll look when I'm not bouncing all over the place.

[Jim Cate]

I just looked, and I can't quite tell for sure if there is a place to put a shackle on the lower fitting.

Ir there is no extra hole, you can substitute a large, high quality s/s shackle whose pin is the same diameter as the current clevis pin. You then attach your snubber to the bow of the shackle.

The down side of this arrangement is that if you need to veer more rode after setting the snubber, you must haul in enough chain to reach the chain hook in order to release it. We installed a waterline level fitting for a snubber on our previous boat for this purpose, but found that iit was more of a nuisance than a benefit under most normal anchoring situations. Still nice to have for extreme conditions...

Jim

[Don C L]

It's been many years but I used to charter a Downeast 38 quite a bit that had a huge snubber on the lower fitting of the bobstay for its all-chain rode. Under calm conditions you can get away without it, but if the boat starts sailing you really need it. At least I did. The bobstay is not intended to take the pressure of rode on it of course. If you aren't sure if the fitting itself is up to it, I'd bolt in a new one below the fitting there that is extra beefy.

[barnakiel]

imho

When the stay is only attached at the top of the bowsprit and the hull, there is only a marginal risk of any damage - and only if any of the elements is of a delicate design - not what you see on open water seagoing craft, where the bowsprit and bobstay must take full force of white, and at times green, water.

Alas, there is also the other bobstay that makes use of an (word?) additional short spar that makes the stay travel to the spar and then onwards to the hull, making the stay bent at the spar. Think of a spreader on a shroud ... In this design, imho, a strong sidewise pull of the anchor rode may dislodge the short spar.

I am attaching an image of the design I think could get broken by a sidewise anchor rode pull.

http://bp0.blogger.com/_UYZvdqG9jyA/...GL+bobstay.JPG

BTW what is the name of that short spar that comes below the bowsprit anyways? My memory, you know.... Apologies!

b.

[Saltyhog]

Originally Posted by barnakiel

imho

When the stay is only attached at the top of the bowsprit and the hull, there is only a marginal risk of any damage - and only if any of the elements is of a delicate design - not what you see on open water seagoing craft, where the bowsprit and bobstay must take full force of white, and at times green, water.

Alas, there is also the other bobstay that makes use of an (word?) additional short spar that makes the stay travel to the spar and then onwards to the hull, making the stay bent at the spar. Think of a spreader on a shroud ... In this design, imho, a strong sidewise pull of the anchor rode may dislodge the short spar.

I am attaching an image of the design I think could get broken by a sidewise anchor rode pull.

http://bp0.blogger.com/_UYZvdqG9jyA/...GL+bobstay.JPG

BTW what is the name of that short spar that comes below the bowsprit anyways? My memory, you know.... Apologies!

b.

It called the dolphin striker.

BTW, I think a better way to lead a snubber to your rode is via a snatch block from the forward bottom of the cranse iron. This is as recommended by the Pardeys and Brion Toss. Leading from the bobstay fitting (at the waterline) results in loading the fittings bolts in tension. They are normally in shear as a member of the rig loads.

[UNCIVILIZED]

I've seen it suggested that you attach a block to the bobstay fitting down at the waterline, & then, with the snubber's chainhook attached to the rode, the snubber goes thru the block, up over the anchor roller, & back to a cleat on deck (or a winch, or the windlass). Which, such a setup would allow you to adjust the length of the snubber without requiring you to pull in the rode in order to disconnect, & reconnect it from the anchor rode.
And there of course could be numerous variations on this setup. Though KISS would be the preferred theme.