What are those wires?

[lindabarzini]

I see several catamarans have wires that go from the front of the hulls (above the waterline) to the center of the bow. What are they called? And what is their purpose?

They seem to pull down the bowsprit where the headsail is located.

[captain465]

On a mono it would be a "Bobstay", I would think that it would be the same on a multi.

[jongleur]

Dolphin striker?

[PaulinOz]

"They seem to pull down the bowsprit where the headsail is located."

That is correct thus stopping the hedasail pulling said Bowsprit up.

[StuM]

Originally Posted by jongleur

Dolphin striker?

I've often heard them called dolphin strikers, but that is not really correct.

A dolphin striker is technically a spar that sticks out below a crossbeam to support down loads such as the mast -the opposite of a "seagull striker"
(Take a look at a Hobie or one of the America's Cup cats).






The wires which run from low on the hulls to higher at the centre do the exact opposite of a true dolphin striker. They are designed to counteract the upward load of a forestay.

Bobstays is a more accurate name for them.

[Alan Mighty]

The National Library of Australia provides a convenient digital version of Billy Falconer's Dictionary of the Marine (1769) based on Thomas Cadell's corrected 1780 version of the same: Bob-stay

Some prefer the horsey term 'martingale'.

[Factor]

Rare that they would be wire these days, all the bowspit lines (called everything form waterstays to guys to simply stays) I have seen on cats these days are dyneema.

[Sailmonkey]

On our beach cats we've been calling them whisker wires. Without them the pole would invert and break.


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[AD28]

If you refer to wire/textile which runs from low on the bows to the end of the sprit, those are indeed bobstay/whisker stay/martingale/sprit stays, which oppose upward loads imparted by headsails like screachers or spinnakers



If you refer to the wire running along the top of the forward crossbeam from one end to the other, supported by a vertical post of some sort (usually A shaped), then that's a 'gull striker' which opposes loads imparted by the forestay



If you refer to the wire running along the forward (or in some cases, mid-) crossbeam under the crossbeam under a post pointed downward (see pic of Hobie 16), then that's a 'dolphin striker' which opposes loads imparted by the mast

[svHyLyte]

Originally Posted by AD28

If you refer to wire/textile which runs from low on the bows to the end of the sprit, those are indeed bobstay/whisker stay/martingale/sprit stays, which oppose upward loads imparted by headsails like screachers or spinnakers



If you refer to the wire running along the top of the forward crossbeam from one end to the other, supported by a vertical post of some sort (usually A shaped), then that's a 'gull striker' which opposes loads imparted by the forestay



If you refer to the wire running along the forward (or in some cases, mid-) crossbeam under the crossbeam under a post pointed downward (see pic of Hobie 16), then that's a 'dolphin striker' which opposes loads imparted by the mast

The vertical strut is the "Dolphin Striker", so named because, if a Dolphin get's him/herself under the thing, whether beneath the mast or at the bow of the boat, he/she may very likely be struck by the strut as the strut descends in a seaway. The Dolphin Striker performs in much the same manner as the spreaders on a mast, to reduce the angle of the cables, or "stays".

The OP's question related to the cables or stays at the bow, between the water line on the inboard side of each bow to the center of the underside of the cross beam. Such cables are properly "bobstays" designed to resist the upward force of the boat's headstay on the cross beam and so minimize its vertical displacement and consequent bending moments.

FWIW...

[AD28]

hylyte

you maybe want to go look all that up and you'll find that I'm correct. Sorry about that. Bear in mind that the question is referring to multihulls, not monohulls

[RABenko]

As the skipper of a classic William Garden designed ketch, I must check in to add my two cents. We too have a bob stay which transfers the load from the forestay to the hull. It is assisted by a "dolphin strike" which is the spar perpendicular to the bow sprit and acts with the bob stay like the spreaders do with the upper shrouds.

[svHyLyte]

Originally Posted by AD28

hylyte

you maybe want to go look all that up and you'll find that I'm correct. Sorry about that. Bear in mind that the question is referring to multihulls, not monohulls

The OP's post was:

Originally Posted by lindabarzini

I see several catamarans have wires that go from the front of the hulls (above the waterline) to the center of the bow. What are they called? And what is their purpose?

They seem to pull down the bowsprit where the headsail is located.

Given the lack of knowledge evidenced by the OP's post, it is difficult to tell whether she is, in fact, referring to to the crossbeam itself as one might infer from the first paragraph; or, in the second paragraph to a "sprit" which "might" be projecting from the cross beam at the bow, save for the phrase "where the headsail is located" which, discriminating parsing of the seems most likely to imply.

Never-the-less, in either case, the stays "...that go from the front of the hulls (above the waterline) to the center of the bow." are, properly, bobstays. In earlier days, such stays were also, occasionally, referred to as "martingales" as their function closely resembled that of the girth straps on drayage horses' halter's, which prevented the animal from lifting its head (as a "headsail" might lift a bowsprit or in the case of a catamoron (sic) the crossbeam at the bows). Nowhere did the OP refer to a crossbeam supporting a mast as on a Tornado although the function of the stays, albeit oriented 180º out from traditional Bobsays, across a striker, would perform a not dissimilar function although introducing an upward thrust rather than a downward "pull".

N'any case, Here Homer Nods...

'tho' I can't help but wonder if "barzini" is of the Sicilian, Corleone, Barzini's

[Factor]

AD 28 is correct

[smj]

Originally Posted by Factor

AD 28 is correct

I agree


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