Broad Reach in higher windspeeds / at night

[meirriba]

Originally Posted by guyrj33

OP wrote:
Lets assume you want to be on a broad reach at night in higher windspeeds. (20-30knts true)

Ok so let's remember a broad reach is 135 degrees.
so the reference from the owners manual for the Lagoon 400 manual is informative but not really on point as it's for CLOSED REACHED TRIMMING (between 75 and 130° to truewind)-.

Yes, your comment is correct.
On the other hand, if you go more downwind (i.e. from reaching to broad reaching) the apparent wind onboard will be lessening.
So, you can use the provided reefing guide, as a safe proposition.

Anyway, in my experience, the wind forces suggested are rather excessive - on our Lagoon400 we reef earlier than the suggested guideline. Never lost speed by reefing earlier...only feeling more secure.

[Snore]

Originally Posted by arsenelupiga

Loads at 125 true and 135 true are not that much away.

It is important to remember that the load on the rig is determined by wind speed and not AWA (more relevant than TWA in this case). Load at AWA 125 at 12kts is much less than AWA at 25.

Originally Posted by arsenelupiga

At 75 true you still have 23 kn app limit, but loads are much higher than at 125 app.

When I teach, even at ASA 101, we discuss the physics of sailing. This is not on the syllabus, but clearly something sailors should know.

From the time the sail inflate, to about AWA 090 the forestay and the shroud share the loads placed on the mast by the wind in the sails. The ratio changes as the AWA increases and the wind moves aft.

When the AWA goes above 090, the load is transferred to the shroud. As AWA goes to 95, the forestay's job is pretty much holding up the jib. As AWA goes up from 95, the load of the jib, through the forestay, now is pulling the mast forward. The entire rig is pulling on the windward shroud.

Usually, up to around 125-130 AWA, the boom is over the traveler. As previously mentioned, the main sheet through the topping lift, is providing some support to the top of the mast. At about 130-135 AWA, the boom is now leeward of the traveler and stops providing any support to the mast.

So--- if you are sailing with an AWA of >130-135 and exceeding the specs in the manual, you are exceeding the recommended loading of the windward shroud, its fittings and attachment points.

Originally Posted by arsenelupiga

Clearly rules are written for IQ 50.

Agreed, the manual is designed to be litigation-proof. I am reading the B&G manual for an upcoming deliver. They disable the auto routing feature in US waters! However, in this case we are looking at loading. Absent a proper analysis, any deviation from the manual is a SWAG. I will only go to SWAG engineering in an emergency, or when the risk is nominal.


If I owned a cat, and on any boat I deliver- we reef her "by the numbers", or earlier if the sea state is ugly. My personal boat was built 40+ years ago, so she is sailed based on less scientific measures. She doesn't have wind instruments!!


I do not want to sound flip, but we may agree to disagree. In the end, this is your boat, you can run her as you feel is best.

[fxykty]

Originally Posted by Snore

It is important to remember that the load on the rig is determined by wind speed and not AWA (more relevant than TWA in this case). Load at AWA 125 at 12kts is much less than AWA at 25.





When I teach, even at ASA 101, we discuss the physics of sailing. This is not on the syllabus, but clearly something sailors should know.

From the time the sail inflate, to about AWA 090 the forestay and the shroud share the loads placed on the mast by the wind in the sails. The ratio changes as the AWA increases and the wind moves aft.

When the AWA goes above 090, the load is transferred to the shroud. As AWA goes to 95, the forestay's job is pretty much holding up the jib. As AWA goes up from 95, the load of the jib, through the forestay, now is pulling the mast forward. The entire rig is pulling on the windward shroud.

Usually, up to around 125-130 AWA, the boom is over the traveler. As previously mentioned, the main sheet through the topping lift, is providing some support to the top of the mast. At about 130-135 AWA, the boom is now leeward of the traveler and stops providing any support to the mast.

So--- if you are sailing with an AWA of >130-135 and exceeding the specs in the manual, you are exceeding the recommended loading of the windward shroud, its fittings and attachment points.





Agreed, the manual is designed to be litigation-proof. I am reading the B&G manual for an upcoming deliver. They disable the auto routing feature in US waters! However, in this case we are looking at loading. Absent a proper analysis, any deviation from the manual is a SWAG. I will only go to SWAG engineering in an emergency, or when the risk is nominal.


If I owned a cat, and on any boat I deliver- we reef her "by the numbers", or earlier if the sea state is ugly. My personal boat was built 40+ years ago, so she is sailed based on less scientific measures. She doesn't have wind instruments!!


I do not want to sound flip, but we may agree to disagree. In the end, this is your boat, you can run her as you feel is best.

Well written and makes sense. On cats the reefing guide is important (and it relies on accurate wind instruments) as the other indicators of overload are relatively subtle (slackened leeward shroud, windward hull rising, leeward hull lowering, increasing rudder loads, increasing sheet loads, others?).

Regarding the transfer of load from forestay to windward shroud as the AWA increases, that may be the reason that cats designed for sailing first (as opposed to accommodations and simplicity of operation) have running backstays. Ours are used in 15+ knots (AWS) upwind to support the forestay and reaching/downwind to support the mast.

If no running backstays, drop the main and use the mainsheet/topping lift combination to support the mast when AWA is greater than 90 degrees. Exactly what the OP wanted to do.

[arsenelupiga]

Originally Posted by Snore

It is important to remember that the load on the rig is determined by wind speed and not AWA (more relevant than TWA in this case). Load at AWA 125 at 12kts is much less than AWA at 25.





When I teach, even at ASA 101, we discuss the physics of sailing. This is not on the syllabus, but clearly something sailors should know.

From the time the sail inflate, to about AWA 090 the forestay and the shroud share the loads placed on the mast by the wind in the sails. The ratio changes as the AWA increases and the wind moves aft.

When the AWA goes above 090, the load is transferred to the shroud. As AWA goes to 95, the forestay's job is pretty much holding up the jib. As AWA goes up from 95, the load of the jib, through the forestay, now is pulling the mast forward. The entire rig is pulling on the windward shroud.

Usually, up to around 125-130 AWA, the boom is over the traveler. As previously mentioned, the main sheet through the topping lift, is providing some support to the top of the mast. At about 130-135 AWA, the boom is now leeward of the traveler and stops providing any support to the mast.

So--- if you are sailing with an AWA of >130-135 and exceeding the specs in the manual, you are exceeding the recommended loading of the windward shroud, its fittings and attachment points.





Agreed, the manual is designed to be litigation-proof. I am reading the B&G manual for an upcoming deliver. They disable the auto routing feature in US waters! However, in this case we are looking at loading. Absent a proper analysis, any deviation from the manual is a SWAG. I will only go to SWAG engineering in an emergency, or when the risk is nominal.


If I owned a cat, and on any boat I deliver- we reef her "by the numbers", or earlier if the sea state is ugly. My personal boat was built 40+ years ago, so she is sailed based on less scientific measures. She doesn't have wind instruments!!


I do not want to sound flip, but we may agree to disagree. In the end, this is your boat, you can run her as you feel is best.

Or you have not read what i wrote or you misunderstood. See bold parts:

"Load at AWA 125 at 12kts is much less than AWA at 25."

your statement makes no sense. What I said is that loads at 125 true wind angle do not differ much than wind angle 135.

And they are more restrictive for 125 angle. For 135 angle only limit is 15 kn boat speed - subject to sea state. this show confidence of Lagoon designers that boat is strong enough to take wind 130+ angle. And this has been proven in reality. Outremer thin hulls may require extra support but lagoon thanks to large weight - is stronger and does not need it.

Sorry, to pop your bubble.

[arsenelupiga]

Originally Posted by meirriba

Yes, your comment is correct.
On the other hand, if you go more downwind (i.e. from reaching to broad reaching) the apparent wind onboard will be lessening.
So, you can use the provided reefing guide, as a safe proposition.

Anyway, in my experience, the wind forces suggested are rather excessive - on our Lagoon400 we reef earlier than the suggested guideline. Never lost speed by reefing earlier...only feeling more secure.

i agree, and i do the same. Often we sail with second reef in sub 15 kn conditions as enjoyment of sailing do not want to end. However I am experimenting, seeing lately how effortlessly boat was sailing at 11 kn, decided to explore boat safety envelope as dictated by reefing guidelines, of course carefully.

[Snore]

Originally Posted by arsenelupiga

Or you have not read what i wrote or you misunderstood. See bold parts:

"Load at AWA 125 at 12kts is much less than AWA at 25."

your statement makes no sense. What I said is that loads at 125 true wind angle do not differ much than wind angle 135.

And they are more restrictive for 125 angle. For 135 angle only limit is 15 kn boat speed - subject to sea state. this show confidence of Lagoon designers that boat is strong enough to take wind 130+ angle. And this has been proven in reality. Outremer thin hulls may require extra support but lagoon thanks to large weight - is stronger and does not need it.

Sorry, to pop your bubble.

Let's start with civility.

I ended my post, with " do not want to sound flip, but we may agree to disagree. In the end, this is your boat, you can run her as you feel is best."

You ended with "Sorry, to pop your bubble."


My only response as a gentlemen is to say, As a professional with many miles behind me, I run by the manufacturer's specs. Breaking a boat because I think I am smarter than the engineers is hubristic.

Snore OUT!

[lituya1617]

Whipping along at hull speed with high winds in the dark of night is a great thing for a 400-ft clipper ship but undue risk for a small sailing boat. If you are in a great hurry to get someplace, perhaps your choice of transportation is unwise? I have learned through sad experience that God separated the dark from the light for a reason: sleep at night because you can't see where you are going!

[reed1v]

Probably wiser to lay ahull at night in those conditions. Otherwise you are asking for a short life.

[fxykty]

Originally Posted by lituya1617

Whipping along at hull speed with high winds in the dark of night is a great thing for a 400-ft clipper ship but undue risk for a small sailing boat. If you are in a great hurry to get someplace, perhaps your choice of transportation is unwise? I have learned through sad experience that God separated the dark from the light for a reason: sleep at night because you can't see where you are going!

You’re kidding, right?

This is akin to our non-sailing friends asking us whether we anchor at night. Silly and ignorant.

Hull speed does not equal whipping along. For most privately owned cruising boats it’s in the range of 6-8 knots, hardly all that fast.

Stopping for 1/3 or even 1/2 of each day would add untenable amounts of time to anything but the shortest passage.

Sailing at night, given light from stars and/or moon, is rarely pitch black. Even when it is completely dark, God did give us ears and the ability to create tools such as radar and AIS and cameras (obviously not infallible given Boris Herrmann’s experience in his recent Vendee Globe collision, but he was asleep at the time).

[JimmyDarci]

Originally Posted by nfbr

I don't like the main on the spreaders. Hence headsail.
Rudders are about 1.5M long - no worries re. centre of effort

As I relax the genoa sheet out the top luffs. Need to pull down.
Sounds like reinforcing the deck and a padeye or track is the go.
I might try the line forward - it may work to pull down.
Need to test that. Thanks

We sail a Crowther and run an extra line forward. Was a fun experiment to get correct balance but not hard and easy to do with no extra deck hardware.

[reed1v]

Originally Posted by fxykty

Have you sailed a cat? Unlike a monohull, crash gybes are pretty much unknown of cats, due to long relatively narrow hulls, dual rudders, and lack of heeling. Cats go downwind or deep reaching, even in big waves, like they’re on rails.

Guess you never sailed a cat on the bay during gusty winds through the slot. Not uncommon to see cats jib, turtle, and just broach all over the place.

[reed1v]

Originally Posted by fxykty

You’re kidding, right?

This is akin to our non-sailing friends asking us whether we anchor at night. Silly and ignorant.

Hull speed does not equal whipping along. For most privately owned cruising boats it’s in the range of 6-8 knots, hardly all that fast.

Stopping for 1/3 or even 1/2 of each day would add untenable amounts of time to anything but the shortest passage.

Sailing at night, given light from stars and/or moon, is rarely pitch black. Even when it is completely dark, God did give us ears and the ability to create tools such as radar and AIS and cameras (obviously not infallible given Boris Herrmann’s experience in his recent Vendee Globe collision, but he was asleep at the time).

A cat will be doing way more than 6-7 knots, more like triple that if not more. Add in cross seas, fixed sails, and auto pilot; then you are taking risks that will catch up with you eventually.

[smj]

Originally Posted by reed1v

A cat will be doing way more than 6-7 knots, more like triple that if not more. Add in cross seas, fixed sails, and auto pilot; then you are taking risks that will catch up with you eventually.

After reading your last few posts I also realize you have absolutely no experience with sailing catamarans

[Factor]

Originally Posted by reed1v

Guess you never sailed a cat on the bay during gusty winds through the slot. Not uncommon to see cats jib, turtle, and just broach all over the place.

In 40 years of multihulling I have never ever seen a larger cat broach. Never

[Nicholson58]

Easy. Staysail and mizzen.

Add a barber to your outside Genoa track and pull the staysail clew wherever you want it.