Why do monohulls sink in hurricanes?

[adlib2]

Originally Posted by a64pilot

Got nothing to do with number of hulls either, in fact I'd bet the average mono will resist more force before being torn apart than the average multi.
Just because it is a whole lot easier to design a very robust monolithic structure than it is to design multiples and tie them together, not because one is superior or any such nonsense.
But it would be interesting to know the cause of sinkings, I have a theory that some at least sink because of the Lazarette. I got to looking at mine the other day and thought how much water it would hold and in the event of a roll over unless the lid was very securely fastened it could come open and allow hundreds of gallons of water into the hull, all of the sudden like. I decided to replace the one easily broken latch with a couple of robust ones

I have two Lazerettes each with a moderately large drain to the bilge housing 3 pumps. Have been through 7 hurricanes and never been a problem; although, don't recommend them.

[Steve Bean]

I recently came across a very interesting free eBook: "The Use of Oil to Reduce the Dangerous Effects of Heavy Seas.". From 1886. It's more than I ever knew about oil on the water.

[ravinracin]

There is a book written by J.C. Voss called Venturesome Voyages published in 1913 where in the last of the book he relates how he and two mates survived a hurricane in a 25'9" monohull yawl using a sea anchor and oil. This insight into his survival gives you a real sense of what a small boat goes thru during a hurricane. It's a very interesting read.

[belizesailor]

Have sailed a 37' mono in hurricane force winds (65kts, gusting 85), near costal, offshore wind so seas never got over 25' nor breaking badly. Serious heavy weather, but never turned into a survival situation. You can survive a lot of wind, but not huge crashing waves.

Its the same ashore, much of the really catastrophic damage done along a coast is by waves on top of storm surge.

Due to lack of huge breaking seas, the boat did fine, we ran before the storm for a while (Sustained over 10 knots under storm jib alone!), then hove to and rode the rest of it out.

[belizesailor]

Another good read that documents what its like to be at sea in a hurricane is "All the Men in the Sea". About the loss of an oil exploration barge, end ensuing rescue, in a cane in the GOM.

[belizesailor]

Originally Posted by belizesailor

Another good related read "Tallships Down" by Daniel Parrot. Analysis of tall ship loses in modern times (hey, they are all monohulls).

https://www.amazon.com/Tall-Ships-Do.../dp/007143545X

The bottom line of Tall Ships Down is that the reason many of these traditional vessels were lost in modern times is change of use and related preparation at sea. Originally they were working cargo vessels, with little consideration for crew comfort (or safety). They routinely survived storms because they were fully battened down for carrying cargo and thus nearly water tight. In modern use they are mostly passenger vessels and most were lost due to down flooding (water coming in down a cargo hatch or similar), because cargo hatches were not battened down properly or were partially open for crew acces/ventilation.

Modern sail boats are lost in severe weather for similar reasons...they simply were never built nor outfitted for that purpose. Most are built to favor creature comforts and look good at a boat show...surviving a hurricane was never a design criteria.

For example, when was the last time you saw a "dead eye" installed on a modern sailing vessel? I expect that most sailors of modern vessels don't even know what that is. It is a heavy bronze cover, usually hinged to the frame of a port hole, which can be closed over the port hole and dogged down...making the port hole water tight even if the lens is blown out. Designed for heavy weather right from the start. Best Ive seen on modern boats is pre cut wooden covers/plugs which owners have fabricated.

[belizesailor]

Originally Posted by adlib2

I have two Lazerettes each with a moderately large drain to the bilge housing 3 pumps. Have been through 7 hurricanes and never been a problem; although, don't recommend them.

Ive seen a couple of boats broach while racing and sink almost immediately due to unsecured lazarette hatches. No hurricane involved...beautiful, but breezy, days in both cases. No loss of life. Both boats recovered...but what a mess.

[SV DestinyAscen]

Originally Posted by Steve Bean

I recently came across a very interesting free eBook: "The Use of Oil to Reduce the Dangerous Effects of Heavy Seas.". From 1886. It's more than I ever knew about oil on the water.

Rain does the same thing - changes the surface tension and helps calms down the sea.

[TheThunderbird]

Few practical tips

Extra covers to blind vents and portholes, little windows...

Fix lazarette openings, and make the stow room water-tight (or full of empty jerrycans...)

Be ready to cut off shrouds and have a lid for the mast section (some silicon can be laid in water..)

Permanent fix of the mast under-roof, to avoid motion

At least a battery atop (lithium?) for emergency
Change seacocks (bronze!) routinely and sail with them all closed, in stormy weather

Stern/bow w water tight doors (have a survival cell amidship)

Check and increase bilge pump system (i have a portable 220V pump with 1"1/2 5m hose pipe getting out of cabin...)

Secure heavy loads below/upon deck

BREAK THE STRAINER LID (glass) of the raw water intake and have the engine suck it through bilge directly, if.... (i got a spare)

Add a mechanical bilge pump to the engine (fishermen have it, not easy on a sailboat)


... a boat ready for hurricane must be re-rigged beyond any customary size.

My forestay was 9mm on furler, hooks allowed me to place 14mm...

Btw, rocks/shore are the greatest danger .. second are seacocks (many more sink in harbours than elsewhere, l deem)... third is an inconsiderate captain with a weak crew (as many abandon boats which never sink)