Unsinkable boats

[Daydream believer]

With a hole that size one would certainly not get watertight bulkhead doors shut in time. Sod's law would dictate that they would be open at the time of collision. Even if the crew were not thrown overboard the shock factor would take a while for them to recover & start taking reactive measures.
What could work would be air bags that could be manually inflated once the crew were clear of the bags. That might prevent sinking but not necessarily an inhabitable craft. Possibly one that would provide support for a few hours whilst help arrived

 

[vyv_cox]

To be fair, Sadler never stated that any of the boats could be sailed when flooded, they only claimed them to be unsinkable. This is evidently true. Personally I would prefer mine as in the photograph than lying on the seabed in the event of major damage as shown.

However, the foam gives enormous benefits in normal sailing. It provides, strength, insulation and sound deadening, all of which are very welcome.

 

[Ric]

No boat is unsinkable, but some of the French built aluminium centreboard cruisers come close. Most have front and rear crash boxes and are double skinned, with water, fuel or ballast between the double skins. I have read accounts of them spending the night bouncing up and down on a reef, then getting towed off with just cosmetic damage.

 

[rogerthebodger]

With a hole that size one would certainly not get watertight bulkhead doors shut in time. Sod's law would dictate that they would be open at the time of collision. Even if the crew were not thrown overboard the shock factor would take a while for them to recover & start taking reactive measures.
What could work would be air bags that could be manually inflated once the crew were clear of the bags. That might prevent sinking but not necessarily an inhabitable craft. Possibly one that would provide support for a few hours whilst help arrived

There was an article in PBO many years ago about using air bags and a dive cylinder to provide inflatable air bags to stop a boat from sinking. I did cousider doing something similar but haven't done anything about it yet.

 

[rogerthebodger]

I suppose its good that its not going to sink within minutes from under you, but that's hardly a habitable boat, it's only the cockpit coamings and coachroof actually above the water.
I'd still be getting into a liferaft than staying on that thing.

Yes but you should still stay with the boat as it can be seen easier and may also have resources that could help you to survive.

 

[Ceirwan]

Yes but you should still stay with the boat as it can be seen easier and may also have resources that could help you to survive.

The fact its not sunk would give you time get resources and abandon ship much more carefully. And if the hole was smaller, more time to effect a repaor. But looking at those photos do you think staying with the boat is really the way to go?

It's awash, there's no shelter whatsoever, you're fully exposed to all the elements, every wave will wash over you.
A liferaft is not great, but it will give better protection than that boat.

 

[davidej]

Can anyone tell me how many lives have been lost due to yachts actually sinking - as distinct to being run down, capsizing etc?

For our normal cruising grounds, Channel, North Sea, Irish Sea etc, I suggest it is vanishingly small.

A lot of solutions in search of an imaginary problem!

 

[blackbeard]

Occasionally boats attempt to sink at moorings while unattended, and are saved when someone notices that the boat is floating a bit low, and investigates, much bailing follows.
Such boats tend to be insurance write-offs, due to damage to engine, electrics etc and water ingress to foam cores, and so forth, cost of repair exceeding value when repaired.
"Unsinkable" doesn't necessarily mean that the boat survives.

 

[Koeketiene]

However, the foam gives enormous benefits in normal sailing. It provides, strength, insulation and sound deadening, all of which are very welcome.

Our previous boat was an Etap38i.
The boat was stiff, dry and very well insulated.

However, we also noted some disadvantages compared to our current - not foam filled - boat.
- Current boat has a more seakindly motion. Doesn't bob on the water like a tupperware box.
- MORE storage space.

 

[pmagowan]

With a hole that size one would certainly not get watertight bulkhead doors shut in time. Sod's law would dictate that they would be open at the time of collision. Even if the crew were not thrown overboard the shock factor would take a while for them to recover & start taking reactive measures.
What could work would be air bags that could be manually inflated once the crew were clear of the bags. That might prevent sinking but not necessarily an inhabitable craft. Possibly one that would provide support for a few hours whilst help arrived

Why would you sail with doors open?

 

[Daydream believer]

Why would you sail with doors open?

Because on a boat that size with crew moving about it would not be like, say, a Volvo, where they might only open the door to get a sail or item of gear, if anything at all.
On a small yacht the compartment will have a more general use ie a berth, or heads, & locking someone in might cause problems.

 

[Tranona]

Can anyone tell me how many lives have been lost due to yachts actually sinking - as distinct to being run down, capsizing etc?

For our normal cruising grounds, Channel, North Sea, Irish Sea etc, I suggest it is vanishingly small.

A lot of solutions in search of an imaginary problem!

Yes - very small numbers. less than 2 a year on average, but many years there are none, and of course one sinking can lead to more than one death. Liferafts are surprisingly ineffective - or rather there are very few documented examples of them working as expected for yachts in our coastal waters, although of course more if you take a world wide view including ocean sailing.

Get onto the MAIB website (and the Irish equivalent) and read the reports. Most, but not all founderings and fatal accidents result in a report and you can learn a lot by reading them.

 

[William_H]

On a typical small sailing boat I would not want foam floatation because as said water gets in and you don't know it and or can't deal with it. However on a typical layout you have an ideal location for sealed compartments in what we might describe as the under bunk (seat) areas near the chine. This might extend from the bow right back to the transom extending in the width of a bunk and to a suitable height. It might fully cover the floor at the bow area to make a big vee berth.
Now this area is traditionally used for storage. If spring loaded hinged and sealed covers were used it could still be used as storage. The volume can be huge. Access inside quite easy. But most important the buoyancy is in the right place to provide righting type buoyancy for the hull. Or look at it another way the water that gets in will be nearer centre line and can not slosh to the sides when heeled. olewill

 

[Daydream believer]

Just how thick is the foam filled hull on a sadler or Etap? I ask because I watched a new mini transat being fitted out & the amount of foam being placed inside must have left very little room for anything else. The hull on a sadler has to displace a great deal of water to keep it afloat

 

[vyv_cox]

Just how thick is the foam filled hull on a sadler or Etap? I ask because I watched a new mini transat being fitted out & the amount of foam being placed inside must have left very little room for anything else. The hull on a sadler has to displace a great deal of water to keep it afloat

Surprisingly little in a 34. The topsides have 1-2 inches, more lower than at the top. There are a couple of fairly large volumes in the aft cabin and forecabin. Stringers beneath the floor are foam filled and structure around the lockers on the port side. We lose a little stowage due to the foam but not enough to prevent us from living comfortably aboard for half the year.