Characteristics of Offshore Yachts

[Jon Eisberg]

Originally Posted by Terra Nova

I have become convinced that it is safer to heave to or trail a drogue from the bow, and wait for the storm to pass. If you try running before the storm, you will just prolong the danger and discomfort, and risk pooping or pitch-poling.

If you're gonna do that, hope you're using an actual 'Sea Anchor', and not just a "Drogue"... :-)

Once lying head to wind in a blow, and large seas, you want to try to arrest any movement backwards, rather than simply slowing it... Don Jordan's series drogue, at least, was never intended to be deployed from the bow...

[skipmac]

Originally Posted by Terra Nova

I have become convinced that it is safer to heave to or trail a drogue from the bow, and wait for the storm to pass.

Have not tried heaving to in a survival storm but have done so in 35-40 kts and found it a great tactic. Instead of crashing and bashing the boat rode level and bobbed up and down with the waves quite comfortably.

Worked great with one boat but another, a modified fin racer/cruiser just didn't like the standard backed main with backed jib. Might have found a combination to work on that boat if I had spent more time on it but it did so well by just reducing sail and bearing off a bit I never got around to it.

Originally Posted by Terra Nova

If you try running before the storm, you will just prolong the danger and discomfort, and risk pooping or pitch-poling.

Cannot completely agree with this for a couple of reasons. First I think the speed of most storms relative to the speed of the boat is such that the boat's speed towards or away from the storm is fairly minor and will not increase or decrease time in the storm dramatically. More important is to look at whether the tactic will take the boat towards or away from the worst weather.

Look at a specific example. You are in the north Atlantic and a hurricane is coming, course due west for simplicity's sake. You are north of the track so in the safe semi circle and rig a drogue off the stern. As the hurricane approaches you will initially see winds coming more or less from the east so take the winds on the starboard quarter and more on the stern as the eye approaches. This will be taking you away from the storm so even if the boat speed is factored in this will be reducing your exposure instead of increasing it.

Bottom line I think one should consider different tactics depending on the situation instead of using only one to the exclusion of all others.

[skipmac]

Originally Posted by Jon Eisberg

If you're gonna do that, hope you're using an actual 'Sea Anchor', and not just a "Drogue"... :-)

Once lying head to wind in a blow, and large seas, you want to try to arrest any movement backwards, rather than simply slowing it... Don Jordan's series drogue, at least, was never intended to be deployed from the bow...

Exactly. A boat lying to a drogue will get an initial burst of speed from a large or breaking wave until the drogue straightens out, slows the boat and holds the end of the boat (preferably the stern) into the wave.

If deployed off the bow the initial speed astern that the drogue allows will put a huge strain on the rudder (and wind vane if you have one). If you deploy something off the bow it should be a proper sea anchor, not a drogue.

[David_Old_Jersey]

As the Nun said to the Vicar......size is important.

All things being equal (which they rarely are. Lol) gonna be a more relaxed experience on a boat in the mid 40" s than low 30" s - if not in "the" storm in the lead up (and after) which should help the crew make better decisions.

The big caveat being boat not too big for the crew to handle.

[Ericson38]

Tommn225 (Bristol 27),

If you can find an Ericson35-3 in decent shape, or the slightly larger but identical basic design Ericson 38, you will be a happy person indeed. We had an '82 E-38 and 10 years later, an '87 E39-200. Liked the earlier one slightly more. In the water 365 days a year, no blisters on either. sailed from beam reach to a beat to weather in fine fashion. Don't need a lot of sail to move, and tankage was good, as was general construction, fiberglass and joinery.

Downwind and very broad reach in large waves, the spade and deep keel will keep you busier than if you were on a Tayana 37, for instance. We had deep draft versions, 15000 DISP, 709 sq feet. Water was 80 gallons on both, fuel was 60. I only wished they were more directional when waves were coming up from behind, but they are strongly built.

Visited the factory in Coasta Mesa a couple of times in the 80s-90s.

[barnakiel]

Displacement (as a proxy for size) is what the nun said.

I think a size bigger than whatever gets toppled over in a regular ocean gale is desirable.

The problem is I can't say exactly what we are talking about in numerical figures. I have see only one author talking about this factor.

How much displacement (or size/displacement) is desirable so that the craft does not get overpowered by regular ocean gale conditions?

NWS JetStream - Wind, Swell and Rouge Waves

Because if we were to assume that even regular gale conditions can overpower a relatively big ocean going craft (say 40+ ft LOA, 12k+ pounds displ) then we can drop the case and stick to our "build it as if you were sure she will get overpowered once and likely more than once"!

Which I believe is the case.

b.

[thomm225]

Originally Posted by Ericson38

Tommn225 (Bristol 27),

If you can find an Ericson35-3 in decent shape, or the slightly larger but identical basic design Ericson 38, you will be a happy person indeed. We had an '82 E-38 and 10 years later, an '87 E39-200. Liked the earlier one slightly more. In the water 365 days a year, no blisters on either. sailed from beam reach to a beat to weather in fine fashion. Don't need a lot of sail to move, and tankage was good, as was general construction, fiberglass and joinery.

Downwind and very broad reach in large waves, the spade and deep keel will keep you busier than if you were on a Tayana 37, for instance. We had deep draft versions, 15000 DISP, 709 sq feet. Water was 80 gallons on both, fuel was 60. I only wished they were more directional when waves were coming up from behind, but they are strongly built.

Visited the factory in Coasta Mesa a couple of times in the 80s-90s.

Thanks for the info. The one I'm looking at is an 84. Seems like an awesome boat.

[Exile]

Originally Posted by Jon Eisberg

If you're gonna do that, hope you're using an actual 'Sea Anchor', and not just a "Drogue"... :-)

Once lying head to wind in a blow, and large seas, you want to try to arrest any movement backwards, rather than simply slowing it... Don Jordan's series drogue, at least, was never intended to be deployed from the bow...

FWIW, John Harries at AAC/Morgan's Cloud has successfully used a Galerider drogue off the bow to help slow forereaching, keep the boat in the "slick," & keep the bow closer to the wind & thus less vulnerable to breaking seas when heaving to. He describes it as a modification to the Pardey's sea anchor/bridle technique. He cautions, however, that his boat already heaves to easily & well, and weighs in at 26T. He's also a strong advocate of a JSD off the stern, especially if things deteriorate into what he calls "survival conditions." As you, Skipmac & others caution, however, different boats will respond differently, so YMMV. Very interesting article on this at their website, although it may now require a paid subscription.

[stevensuf]

Size counts, plain and simple, I'd rather be in a 40ft bendy than a 30ft tank when it comes to survival situations and to those full keel jobs, beam on to waves they can trip over their keels, whereas that fin keeler who has less lateral resitance can accelerate down the side of the wave better.

A bigger boat has more chance to get out of harms way as it is in general faster, a bigger boat is far less likely to be rolled.

As to AVS and self righting, a narrow beamed boat which has a high avs say 150 upwards will self right far quicker than a boat with an AVS of say 120, but you will find the boat with the AVS of 150 will have a smaller beam meaning a far smaller wave will capsize it in the first place.

You may find it works out like a 12ft beamed 45 ft length boat will be capsized by 12ft of breaking wave but will self right almost immediately , whereas a 15ft beamed 45ft boat will need 15ft of breaking wave to capsize it, but will remain inverted longer before righting.

Now the difference in a storm creating 12ft to 15ft of breaking wave is significant, 15ft of breaking. wave requires a significant leap in energy over 12ft of breaking wave (and by breaking wave we mean the part of the wave at the top that is breaking not the whole wave) .

In a strom you're gonna be a lot safer in that 40ft bendy than that 32ft westsail.

And how many boats will survive a roll intact? Better not to be rolled in the first place!!

Some say you will not get caught in a storm due to comms/forecasts, well 5 days out at sea and all the comms/forecasts will still see situations where a storm cannot be avoided.

If you are going serious offshore then get as big a boat as you can afford/handle.

Lastly when comparing very simmilar AVS boats look at the coach roof, more rounded will self right quicker than flatter decked boats.

[TeddyDiver]

Originally Posted by stevensuf

Size counts, plain and simple...

As to AVS and self righting, a narrow beamed boat which has a high avs say 150 upwards will self right far quicker than a boat with an AVS of say 120, but you will find the boat with the AVS of 150 will have a smaller beam meaning a far smaller wave will capsize it in the first place.
....
You may find it works out like a 12ft beamed 45 ft length boat will be capsized by 12ft of breaking wave but will self right almost immediately , whereas a 15ft beamed 45ft boat will need 15ft of breaking wave to capsize it, but will remain inverted longer before righting.
....
In a strom you're gonna be a lot safer in that 40ft bendy than that 32ft westsail.
...
And how many boats will survive a roll intact? Better not to be rolled in the first place!!

Size counts but's not the only thing. The displacement, draft and CB play big role and may happen that the odds of capsizing may be quite the opposite you suggest. Remember beam while it brings initial stability also makes the boat heel more with the breaking the wave and make it more prone to capsize. This has been studied by many NA's ove rhe years.
BR Teddy

[skipmac]

Have to completely disagree with the size counts plain and simple.

In rough weather maybe not as much a factor but if it gets to survival storm level I would always opt for the 30' tank over a 40' "whatever you want to call it". Not going to say Bendy or Hunter or any other brand but just say a boat that"

- is lightly built in general which includes: chainplates and attachments, hull deck joint, thinner layup, lighter hardware, minimal backing plates, etc
- has large windows
- large cockpit with moderate to small drains

Certainly bigger will be less likely to roll, will have an easier motion, better chance to punch to windward off a lee shore but you cannot discount overbuilt in really, really bad weather. Smaller may get rolled but properly built the boat will stay in one piece.

Read an analogy years ago that I thought interesting. Take one of those small, cheap, red and white plastic fishing bobbers and toss it in the ocean. The biggest wave ever would not break it. It would roll, submerge, bounce but not break.

Build a boat, whatever the size, strong enough and a built to keep the water out. It might roll, bounce, even submerge in a giant breaking wave but it will stay afloat and keep the occupants alive and that is bottom line.

[mstrebe]

Size (including ballast) is the most important factor in ability to stand up to breaking waves, full stop.

Anyone who thinks its okay to roll in a boat has never done so. You're done sailing when that happens. Your rigging is not going to survive it in tact, especially if you have any sail aloft. Few if any of your systems are going to survive.

A storm that rolls you once is going to roll you again and again. No ship is so secure for sea that the crew won't be beat senseless by loose gear when it rolls.

When its all over with, you'll have an exhausted, injured crew on a boat that has lost its rig, and your only option is to await rescue. Your boat has become nothing more than a lifeboat at that point.

No thanks. Size improves survivability in a storm at the square root of its waterline, but storm energy increases on an inverse logarithmic scale, which means that there's a size above which the odds of being capsized by a wave drop below the threshold of acceptable risk. There are many other _minor_ factors, but none of them matter as much as size with proper ballast. Not even close to as much.

When I was in the Navy, we accidentally rolled a small-boat during exercises with our ship's wake. The wake hit them wrong, and a 24' motor whaleboat was rolled by an 8' wake. Of the four sailors aboard, one died instantly of a head injury, two others were seriously injured and incapacitated, and one was uninjured. He had to bring the boat in. He said the boat "just barely" rolled, and he thought they had countered it. Had it been just a little longer, they'd have laughed off the incident over beers in the next port of call. Yes, a motor boat is a different beast than a sailboat, but size matters and rolling isn't some kind of panacea.

[TeddyDiver]

Originally Posted by mstrebe

Size (including ballast) is the most important factor in ability to stand up to breaking waves, full stop.
Dynamic stability, STOP Size helps thou

Anyone who thinks its okay to roll in a boat has never done so. You're done sailing when that happens. Your rigging is not going to survive it in tact, especially if you have any sail aloft. Few if any of your systems are going to survive.
Sure, not okay to roll but size has nothing to do with rolling. Long rolling period eases the affect on the crew. Damping against rolling comes from the hull form and wetted area including keels etc and possible antirolling gears. Speed increases stabilty against rolling.


A storm that rolls you once is going to roll you again and again. No ship is so secure for sea that the crew won't be beat senseless by loose gear when it rolls.
No ship secures gear, crew does..

When its all over with, you'll have an exhausted, injured crew on a boat that has lost its rig, and your only option is to await rescue. Your boat has become nothing more than a lifeboat at that point.
Think inverted, you might figure a few things to avoid such a mess. A lot of boats have survived intact roll-overs. Others drop their keel and break their mast in moderate conditions. I say horses for courses

No thanks. Size improves survivability in a storm at the square root of its waterline, but storm energy increases on an inverse logarithmic scale, which means that there's a size above which the odds of being capsized by a wave drop below the threshold of acceptable risk. There are many other _minor_ factors, but none of them matter as much as size with proper ballast. Not even close to as much.
You are right about ballast. Besides size some structural integrity also helps.

When I was in the Navy, we accidentally rolled a small-boat during exercises with our ship's wake. The wake hit them wrong, and a 24' motor whaleboat was rolled by an 8' wake. Of the four sailors aboard, one died instantly of a head injury, two others were seriously injured and incapacitated, and one was uninjured. He had to bring the boat in. He said the boat "just barely" rolled, and he thought they had countered it. Had it been just a little longer, they'd have laughed off the incident over beers in the next port of call. Yes, a motor boat is a different beast than a sailboat, but size matters and rolling isn't some kind of panacea.
Excersice? Boys playing stupid

Comments red.

[stevensuf]

If anyone cares to dig, there are some interesting videos on youtube, by some English university on Wave tank trials, they made models of various boats , various keel ballast ratios, and they found that they made very little difference.

A breaking wave equal to your beam will roll you, plain n simple! IE if you have 14ft beam then 14ft of breaking wave will roll you, The AVS or ballast ratio made no difference to this fact! Yes if you make the ballast ratio too small then a wave less than the beam could roll the boat, but we are talking extremely small ballast ratios here.

Most boats with a high AVS tend to be skinny beamed and thus are more likely to be rolled in the first place than a boat of simmilar length but with a wider beam. The Higher AVS boat will probably self right pretty quickly, while the lower valued AVS boat may will take longer to right.

How long would i take to fill a 40 footer with water compaired to a 30 footer?

So again i retiterate, In a storm you are better off in 40ft of bendy toy than 30ft old skool tank, by a huge margin!

[skipmac]

Originally Posted by mstrebe

Size (including ballast) is the most important factor in ability to stand up to breaking waves, full stop.

If you mean avoiding a rollover or pitch pole then yes, size is a very important factor.

Originally Posted by mstrebe

Anyone who thinks its okay to roll in a boat has never done so. You're done sailing when that happens. Your rigging is not going to survive it in tact, especially if you have any sail aloft. Few if any of your systems are going to survive.

If you are referring to my post, in no way did I say or imply that rolling a boat was OK. No way, not at all, never is that a good thing. I don't think anyone on the planet would think otherwise.

And of course you will probably lose the rig. I thought that would go without saying.

But choosing between a smaller boat that rolls but stays afloat vs a larger boat with greater comfort and stability that doesn't roll but breaks up in the storm and sinks? I'll take the rollover. That was the point I was trying to make in rebuttal to a couple of posts that were implying that size is all that matters, to the exclusion of all else. Size matters but you cannot ignore other factors.

So in a rollover certainly there is a risk of serious injuries or death but you do have a chance to survive. Sinking in a survival level storm your odds of survival are zero.