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shantycrew · 11-02-2014, 11:37

We've got a Hardin sea wolf that has a six foot bowsprit which has the steel wire stay that I think we call the dolphin striker, going from a fitting at the base of the prow to the outer point on the bowsprit. It's a pretty substantial bit of steel wire but when I have a pair of snubbers led through the fair leads these chafe on the stay putting substantial pressure on it. As the boat moves from side to side in the strong trade winds here at anchor in Puerto Rico I'm concerned that there may be too much pressure that could do damage to the dolphin striker.
What can I do to stop this happening, should I just hang the anchor chain off the bow roller and forget about snubbers altogether, or do you have a better solution.

**Hudson Force** · 11-02-2014, 11:47

Is it a situation like this?

... The best solutions that I have seen are achieved by having the snubber led from a shackle fixed at the point where the cable of the dolphin striker meets the hull. The end of this line is kept tied at the bow pulpit when not in use and attached with a chain hook on the rode at anchor.

I realize that this photo shows the chafe on a mooring line and not the snubber, but the same solution would apply. An additional advantage to having the snubber on a shackle at the low point at the water line would be that it creates a lower lead for the rode and better holding at anchor.

Vasco · 11-02-2014, 12:46

Yes, have the snubber led to the chainplate at the bottom of the bobstay.

Sailmonkey · 11-02-2014, 12:52

Quote:

Originally Posted by Vasco

Yes, have the snubber led to the chainplate at the bottom of the bobstay.

I've thought about doing this on our bobstay, then didn't as I was concerned about the unknown side loads imparted on the chain plate.

F51 · 11-02-2014, 13:07

Check out page 88 of Brion Toss' "The Rigger's Apprentice." I rigged up a large block shackled to the cranse iron and ran my snubber line thru this block and then down to the anchor rode. Cleat off the snubber and then pay out more chain thru the bow roller, so that the load is taken on the snubber. This keeps the snubber off the bobstay and seems to help some with sailing back and forth at anchor.

AnchorageGuy · 12-02-2014, 07:00

Shantycrew, Our Mariner 40 Ketch survived 15 named storms, 12 of those hurricanes, and many at anchor. We always were in a protected anchorage but in all that time, neither the stay, the striker, the anchor rode or the snubber ever had a failure or unusual wear as a result. It did rub on the stay as the boat would sail at anchor. We used a piece of hose as chafe gear on the snubber where it rubbed on the stay. But that's all we felt we needed to do. Chuck

shantycrew · 12-02-2014, 11:13

Thanks all, and yes captforce, that looks just like our bowsprit. I think I got concerned when we took a turn around the harbour here in Salinas, Puerto Rico and noticed that one boat that had been left a while had a broken strainer, not sure what the boating name is for it, but it's the steel rod that holds the stay away from the hull.
We noticed that most of the larger boats had two snubbers, from the port and stb. fairleads, so we went for that.
As for anchorage guy, well sounds like that bit of the boat must be strong enough to survive the forces, but is it the same with all boats, obviously not with the one we saw in harbor here.
As to F5 solution, I don't think I've got much room for any kind of shackled block, but like that as a solution although as sail monkey says, what about the side forces on that chain plate, now that could be a concern, a big concern as ours is a heavy boat and dances about alot in the afternoon trades that can gust up to over 30 knots.

**Hudson Force** · 12-02-2014, 17:02

Quote:

Originally Posted by shantycrew

.......... a big concern as ours is a heavy boat and dances about alot in the afternoon trades that can gust up to over 30 knots.

I always thought that the light weight "featherdusters" with the fin keels were more likely to exhibit a lively dance at anchor. Have you tried two snubbers at a more aft point at a wider beam led to the chain well forward of your bow? Can you decrease your lively dance with more windage arranged on your stern? Is your trim,- fore & aft, level? Another thought is to accentuate a lie off the wind by taking an extremely long "snubber" from one quarter all the way to your anchor chain where it meets a short snubber from the other side of your vessel. Shortening the longer snubber will draw you off the wind and cause to to remain with one side more to the wind and your dolphin striker further from the longer rode, but balanced off the shorter one too. This might stop the dancing, but then it might decrease that pleasant breeze through your cabin!

Pelagic · 12-02-2014, 18:00

Agree with Captn Force….

Living in a Typhoon area I use a bridal of 2 heavy snubbers, secured further aft on strong Samson posts that are protected from chafe.

We let out about 15 ft of slack anchor chain and this bundle slows down veering considerably and adjust bridal so that surface point is aft of dolphin striker.

Depending on wind strength, we play with bridal length to keep it clear of striker.

EDIT... Not sure why photos do not display as it shows on preview... tried 3 times to load

S/V Alchemy · 13-02-2014, 07:32

Quote:

Originally Posted by CaptForce

Is it a situation like this?

... The best solutions that I have seen are achieved by having the snubber led from a shackle fixed at the point where the cable of the dolphin striker meets the hull. The end of this line is kept tied at the bow pulpit when not in use and attached with a chain hook on the rode at anchor.

I realize that this photo shows the chafe on a mooring line and not the snubber, but the same solution would apply. An additional advantage to having the snubber on a shackle at the low point at the water line would be that it creates a lower lead for the rode and better holding at anchor.

This is correct. Many setups like this have a plate or similar fitting glassed in or as part of a weldment. It consists of a heavy "tab" with a hole above for the dolphin striker/bobstay and a hole below to take a shackle for the snubbing line to bring the attachment point of the anchor both forward of the boat and down to the waterline. The effect is much like mooring in terms of dampened movement. It's a better method, IMO, than the typical bridle off the bow fairleads...BUT...if you have chafe due to the bridle lines rubbing against the bobstay, I would suggest you are swinging overmuch and need to do two things: a) lengthen the bridles and b) set up a riding sail to dampen the tendency to swing on the rode.

S/V Alchemy · 13-02-2014, 07:36

Quote:

Originally Posted by CaptForce

I always thought that the light weight "featherdusters" with the fin keels were more likely to exhibit a lively dance at anchor. Have you tried two snubbers at a more aft point at a wider beam led to the chain well forward of your bow? Can you decrease your lively dance with more windage arranged on your stern? Is your trim,- fore & aft, level? Another thought is to accentuate a lie off the wind by taking an extremely long "snubber" from one quarter all the way to your anchor chain where it meets a short snubber from the other side of your vessel. Shortening the longer snubber will draw you off the wind and cause to to remain with one side more to the wind and your dolphin striker further from the longer rode, but balanced off the shorter one too. This might stop the dancing, but then it might decrease that pleasant breeze through your cabin!

Also a good suggestion. If you are getting the sense that this might involve experimentation, you are right. The balance points of boats at anchor, their inherent tendency to swing, the variable windage and the effect of tidal or river current plus (or minus) wind on the boat mean you can only acknowledge generalities and then refine for your specific vessel and situation.

It's educational to watch other boats at anchor and to figure out why some are sitting more or less quietly and others are not at all, under near-identical conditions.

ryon · 13-02-2014, 08:19

Not to be pedantic but,.. aw, who am I kidding, I love to be pedantic! The dolphin striker, or martingale, is a short, nearly vertical spar running from the forward end of the bowsprit down to the martingale stay, which runs from a chainplate on the bow, forward to the lower end of the martingale, then to the forward tip of the jibboom. The lower point will usually be decorated with a spearhead to make it look cool.

I have no idea how to answer your question though. Most of the ships with this sort of headrig have hawsepipes where the anchor chain emerges below the level of the martingale stay. The bobstay, running from a chainplate near the waterline to the end of the bowsprit will be stout, and protect the bow from the anchor rode.

(I think I just set a record for the number of terms the spellchecker doesn't recognize, hee hee!)

S/V Alchemy · 13-02-2014, 08:27

Quote:

Originally Posted by ryon

Not to be pedantic but,.. aw, who am I kidding, I love to be pedantic! The dolphin striker, or martingale, is a short, nearly vertical spar running from the forward end of the bowsprit down to the martingale stay, which runs from a chainplate on the bow, forward to the lower end of the martingale, then to the forward tip of the jibboom. The lower point will usually be decorated with a spearhead to make it look cool.

I have no idea how to answer your question though, most of the ships with this sort of headrig have hawsepipes where the anchor chain emerges below the level of the martingale stay. The bobstay, running from a chainplate near the waterline to the end of the jibboom will be stout, and protect the bow from the anchor rode.

(I think I just set a record for the number of terms the spellchecker doesn't recognize, hee hee!)

Yeah, I think you're right, but terminology seems to vary over the English-speaking world and so I just went with it. I call it a "bobstay", myself, and it doesn't just protect the bow. It counteracts (or "stays") the tension of the forestay, which would otherwise tend to bend the bowsprit upward.

Some bowsprits are inherently strong enough to not really need a bobstay, or they are braced (like the sprit of some J-Boats) far enough back inside the boat to have a few feet forward of the bow. But in most cases, a bobstay is part of the standing rigging.

ryon · 13-02-2014, 08:50

Quote:

Originally Posted by S/V Alchemy

Yeah, I think you're right, but terminology seems to vary over the English-speaking world and so I just went with it. I call it a "bobstay", myself, and it doesn't just protect the bow. It counteracts (or "stays") the tension of the forestay, which would otherwise tend to bend the bowsprit upward.

Some bowsprits are inherently strong enough to not really need a bobstay, or they are braced (like the sprit of some J-Boats) far enough back inside the boat to have a few feet forward of the bow. But in most cases, a bobstay is part of the standing rigging.

You're quick! You posted before I could correct my mistake. I think we agree on terminology. Of course, the bobstay runs from the lower chainplate to the end of the bowsprit, not the jibboom. On a large ship, these are two different structures, with the bobstay being the stubby projection of the bow, and the jibboom the long spar running forward to support the forestays. The martingale stay is the stay that opposes the upward force of the forestays, and the martingale, or dolphin striker the short spar standing off the martingale stay. I'm not sure about small boats though, I'll guess the terms bowsprit and jibboom mean the same thing.