Boat/seastead survival in a hurricane

(Bob LLewellyn) #1

Looks like that but I can’t take any measurements from here. And when hurricanes hit land, they become dangerous because there are plenty of things to throw around. At sea, there is only water. Give me a sound water tight boat over facing a hurricane on land any day. Even living in a brick house can’t prevent floods. No water surges because the boat will just raise with the tide (surge).

The thing is, if we expect to have high wind and waves, we can build to account for them. But we don’t have to build for earth quakes or tornadoes. We don’t have to deal with rodents or bugs, all live stock is in the water, not usually above it where humans tend to dwell. Wind or no wind, it’s just safer at sea (with the right equipment, of course).

But thanks for looking out for me Mati.

A Marinea Update

The crew of the SS El Faro might disagree … if any of them had lived to tell us about their hurricane wind damage.

(Bob LLewellyn) #3

I remember that, the key to her demise was “after losing propulsion”, V hauls need to be under power or she we flip side ways. Flat bottoms do not need to be under propulsion to be stable. She could have out run the storm but for the fouled power train. Not a real good example.

(.) #4

may be I post it in a different compartment

(Bob LLewellyn) #5

Weather from Sal Bank during hurricane Irma which went right over the islands.
The Florida Straights is the deep area between Miami and the Sal Bank, the Nicholas Channel is the deep area south of the Sal Bank - north of Cuba.

Nicholas Channel Location 23.4 / -80
Winds: SSE 69 to 94 knots.
Seas: SSE 36 feet at 12 seconds.

Sal Bank Location 23.5/ -80
Winds: S 52 to 71 knots.
Seas: S 13 feet at 7 seconds.

Florida Straights location 24.5 / -80
Winds: SSE 61 to 82 knots.
Seas: SSE 32 feet at 12 seconds

From this info, we can see the shallowness of the Sal Bank attenuates the wave size and period. Both south and north are 30+ feet while right between them, the bank is only 13 ft. This means a 75 ft boat could ride out the worst hurricane in recorded history by hiding behind an island. For safety sake we will add another 25 ft and suggest anyone living on a boat less than 100 feet should sail away from the village and take your boat to safety. Don’t worry, there will be no traffic problems.

Info from


I’m not sure why you think a flat-bottom without any propulsion won’t be subject to wind damage during a hurricane, Bob.

I’d be interested in looking at some analysis of that.

I like your project, but not that particular claim.

(Bob LLewellyn) #7

That’s not analysis my friend, that’s experience. I have a merchant seaman’s document, worked the shrimp boats out of Tampa, and worked the barges from Pittsburgh to New Orleans and into the gulf. When you pull a barge it will track left and right but never right behind yet when anchored, it doesn’t dance and roll like ships or boats do. Waves breaking over the bow and I could still stand on the deck. Now, I’m not stupid, in any wind or weather, I would aways wear my strap when I had to go out in it.


Good attempt at moving the goalposts, Bob … but a fail at responding to the request actually asked.



On the other hand, because the lagoonal surface in Cay Sal has a depth of 30 to 52 ft only, those waves will be choppy. Just look at the frequency, 7 seconds vs. 12-13 seconds…

Choppy waves are more dangerous than longer, bigger swells, specially in shallow water where they carry more kinetic energy since they are bouncing off the bottom.

LOL. Riding cat 5 Irma @ anchor in Cay Sal on a 75 footer would have been suicidal. No captain in the right mind would have done that.

A flat bottom barge + without engine ?? would be the worst vessel to ride any hurricane at anchor. Period.

ALL the 1000’+ LOA cruise ships operating the Caribbean Sea have left for shelter A WEEK AGO.

(Bob LLewellyn) #10

Woa, I didn’t say it would not get any damage but mostly to breakables inside. Barges are made from steel strong enough to carry a heavy payload. Mostly empty as a live-aboard would be, would ride high and dance more than loaded but I will in turn ask where you got the idea that a flat bottom would behave the same as an almost round V haul boat would?

I can’t tell you why, but it doesn’t roll like ships do. I suppose I could speculate like everyone else that it is because the waves are more uniformly dispersed under the flat bottom but I would be lying if I told you that I knew why that these things happen, I don’t have a clue as to why.

Octavian, I’m a bit disappointed in you, when did you become the spokes person for every captain out there.? That’s not like you. I’ve been through hurricane winds at sea. Not close to the eye-wall but enough to have actually sailed in 15 foot seas. It would not be anyone’s first choice to ride out a storm like that, everyone that could leave should but I would expect that when we got back, the barge would be in fine shape.

However, this discourse has taught me something important. If people that are planning to make and presumably live on a floating anything, are showing this much concern about weather at sea, we are going to have a tough time convincing newbies that they can live safely at sea. Maybe the reason no one has been able to develop a floating village before this is because they could not calm the fear of the inexperienced. We may end up failing if we can’t figure out how to do this. Now I’m not so hopeful.


Try again with a different phone claim.

I never made that one.


I wrote something completely different, Bob …

Remember … I asked why YOU think that.

(Bob LLewellyn) #13

Oh, sorry Bob, it’s 2 in the morning and my eyes are blurry, I’ll try to read more carefully.


As in the comment I posted …

(Bob LLewellyn) #15

The answer is from actual experience but anyone can check out the difference by riding on a Cat or pontoon boat and then on a regular v haul boat of the same size. Maybe it’s because the width is greater on a barge than on something intended to be moving all the time. I really don’t know but the side-ward vectors do not seem to be as great.

Now days, those stabilizers takes away the side-ward roll like there wasn’t any waves out there. I would think that we could use stabilizers on a flat bottom something but I’ve never seen it done.


Well, I am a bit disappointed in your sensationalistic claims too.

In my experience, weather at sea should be any future seasteader first and constant concern.

(Bob LLewellyn) #17

No more so than on land.
The latest report that I saw was 40 killed by Irma, how many were lost at sea?
How many lost to forest fires,
How many to tornadoes,
How many to traffic accidents,
How many to floods,
How many have died because of land based governments?

In my experience, trying to stay alive on land should be any future persons first and constant concern. Not to mention terrorist bombings, street riots, bystander to a drug deal gone bad, and if I don’t quit, I will scare myself out of ever leaving my house which I eye with suspicion.


Bob, you can believe anything you want on your own seastead.

BUT YOU CAN’T do whatever you want on it because Maritime Law will held you criminally responsible for your actions AND inactions. We’re dealing with people life on a seastead, not cargo.


Overall, a seastead survival in a hurricane is a simple 3 words phrase: RUN TO SAFETY. If you can’t run since you built a “stationary” seastead, sooner or later you will get screwed…

Which brings into the conversation the subject of seastead’s mobility. No seastead should be built without self propulsion and without a minimum 1000 nm (nautical miles) cruising range fuel capacity.

Therefore, seastead design should follow the mobility function, meaning that, no matter if small modules rafted up or a medium-large-huge floating structure, ALL should be built “as a boat”, with navigation and seakeeping abilities.

Anything else is just amateurish, pipe dreams fantasies.

(Wilfried Ellmer) #20

@Octavian | you postulate that the existance of hurricanes creates the automatic need of propulsion and fast speed. This is a very universal postulate .

• What about building the seastead outside of the hurricane zones ?
• What about having hurricane shelters “you can run to” on the seastead itself ?
• What about building the seastead to the quality of a “hurricane shelter” in first place ? (so you don´t need to run anywhere - as you are already there.)
• Why ship captains move their ships out to open water as default hurricane strategy if your postulate has universal merit ? (all irresponsible criminals ?)

The SS Faro is only the misleading part of the statistics - one of the few modern ships that did NOT survive in open water - the other part of the statistics, that needs to be told, to get the whole picture is, that thousands actually do survive hurricanes in open water all the time … they are just not in the news when they do - it is a unspectacular part of dayly global commerce and business.

I have not posted anything on somebody elses thread (@ForexBob sorry for the butt in - it is your thread…) for a couple of months and i will limit my presence further - but this is one of those “postulates” that needs “calling out” for the sake of seasteading in general…and @Octavian is a poster who has a reputation to be taken serious (in my universe)…so his postulate deserve a “peer review style answer” (i would not molest to answer if the postulate came from a notorious crap poster ) in the end i post this to bring the discourse back to a sane track, that allows for "any kind of future for seasteading " - not as a destructive criticism, please take it as such… @Ellmer out again.

Postulate: Floating Cities that move faster than the track of a hurricane are not very likely ... so "run as only strategy" is a bit short.

• Why is Prelude designed for a stay and survive in category 5 cyclone strategy if “run” is the only “non criminal” option…as postulated.

• Why is no oil infrastructure desiged to disconnect and run in case of a hurricane ? - might it have to do with FEASIBILITY ... of moving around things beyond a million tons fast and on demand on short notice...(it is not a bicicle or a boat - it is supposed to be a CITY after all...)
• Why are land cities not designed to run away from bad weather ?
• How has "City evacuation due to weather" in practice panned out when intended...check New Orleans...
• Postulate: What diferentiates a "camp" from a "settlement" is that a settlement does definitly not "run away from weather".