Fibreglass Boats and Damage Control

[Owly055]

http://www.caribbeancompass.com/damagecont.htm

The following is the first paragraph in a good article by a marine surveyor.   One of my concerns about blue water sailing is the fact that modern boats have virtually no measures to contain flooding....... The boat sinks, you paddle away in your life raft and pray for rescue.  All your supplies are on board the boat at the bottom of the ocean.   It doesn't have to be this way.  It is possible to create enough boyancy to keep a damaged boat afloat, and here are a few ideas.  Water tight bulkheads could in my opinion be incorporated into a small (30') sailboat, dividing it into 3 major compartments, and other measures such as water tight lockers and other storage areas can provide boyancy.  Liners have created a situation where it can be impossible to reach a damaged area.... I'm not a fan of liners anyway.  A boat with a small aft cabin like the Nor'Sea 27, that incorporates what would be quarter berths into the  aft cabin, could in theory be designed to have 3 major divisions.  The aft cabin, the main saloon, and the area forward of the main saloon. Access between the saloon and the aft cabin are not necessary, as both open into the cockpit.  That leaves the forward bulkhead as being the only one that needs a true watertight door / hatch.   This article addresses a concern of mine that applies really to all boats used on long passages.   Contrary to what was written here, there are resins that can be successfully used in underwater fiberglass repair.   I've read an account of Splash Zone being used under water successfully to repair a damaged hull.... it was at the dock, but it WAS underwater.   http://www.pettitpaint.com/product_category.asp?id=21

                                            H.W.

"Fibreglass Boats and Damage Control

        by Hugo du Plessis

Are fibreglass boats safe to go to sea? Such a question, daring to cast a doubt about fibreglass boats, will I am sure bring heaps of abuse on my head and indignant denials from every builder, as well as endless reports from owners of fibreglass boats who have crossed oceans, as I have myself, and sailed round the world. So I add hastily, before being burnt at the stake as a heretic (not for the first time! I was the first to dare to suggest that fibreglass boats needed maintenance), that it does not apply to fibreglass boats in general, or indeed to fibreglass as a material. The principle problem is the way most fibreglass cruising boats are designed and built, in particular regarding the difficulty, even the impossibility, of damage control - a very important factor when far from land and help. "

[CharlieJ]

"I've read an account of Splash Zone being used under water successfully to repair a damaged hull.... it was at the dock, but it WAS underwater.   http://www.pettitpaint.com/product_category.asp?id=21"

I've done that- we were anchored in 6 1/2 feet when a thunderstorm blew through- boat draws 3 1/2 feet. We slammed bottom in a trough.  Started taking on water. Dove, felt around and found crack. Mixed Underwater epoxy ( here it's called "black and yellow") and shoved it into crack. Several days later, hauled out and repaired completely But it slowed the leak almost totally. At least  we only had to pump a gallon or so every day.

I always carry the stuff.

[CapnK]

Food for thought/speculation: I've thought a lot about this topic over the years, and will likely continue to do so my entire life, as I intend to live on a boat until they throw me off of it to feed the crabs. :) I had a brain flash while thinking on it again this AM. Current boat, the Islander 36, in its current OEM state, is a typical example of the type of fiberglass boat which could be deadly to get holed while at sea, because cabinetry built into the liner makes the hull inaccessible in an easy-ish manner over probably 50% of the boat.

Yet for the sake of pure survival, I don't believe that you need to be able to immediately fix a holing, or that that in fact is even your top priority!
What is, is this: you must control the amount and location of a catastrophic flooding, prior to being able to stop it.
In this, compartments are the key - if you can mostly keep the water confined to 1/3 or 1/4 or less of the interior area in the boat, then your problems are going to be MUCH easier to deal with.

In order to see this in the real world, I suggest this as an "experiencement", so you'll have an idea of what you might be dealing with:
Get a dinghy which has positive flotation, take it out on a good choppy day and fill it up with water, and climb in (if you can! You might better fill it with you already in). What you'll find is that when you have a large volume of water able to roam at will within the confines of a hull, even one as small as a dinghy, it becomes extremely tippy and uncontrollable, and even with positive flotation, will roll such that bailing out to a point of getting everything dry again will have to wait until the sea state is such that it is basically calm.
Otherwise, that water in the boat constantly rolls the gunnel or stern or even bow under water, shipping more than you've been able to bail since the last time it scooped up a load. Scale that up to a 25'+ footer with positive flotation, decks nearly awash but still able to float, and you literally have *tons* of water rushing about inside your boat with every movement of the ocean outside, even if you have managed to stop the sinking.
Seriously - try this in a dinghy - you'll get a whole new appreciation for what it would probably be like to have a boat mostly filled with water out on a heaving sea. Trust me, I know (by doing the above in a sort of "accidental experiment"... ;D ).

So - compartments. Places where you can contain and thus control the water taken in. If you have a watertight anchor locker, and your cockpit lockers/lazarette are likewise sealed from the rest of the boat, that might be 15-25% of your boat sink-proofed already, leaving only the cabin space to deal with.
For this, the Navy uses bulkheads and watertight hatches, and while that works fine for ships and subs, it will take up a lot of space in a sailFar boat, as well as being heavy and expensive.

Much easier to implement would be 'slat board coffer dams' that could be inserted into a framework at your current bulkhead openings. If the bulkhead is well-sealed to the hull, then these boards would be able to keep the water confined to the holed area of the boat, whether that is the fore, middle, or aft. Put some gasket material on their top and bottom edges so they can seal against themselves, lash them down, and you are probably one-third or halfway done towards fixing your emergency.
In fact, if you were set up this way, it might even be smart while at sea to leave all your bulkhead openings halfway 'dammed', say up to a step-over height. It would make it a little inconvenient when moving fore and aft through the boat, but you could mitigate this by putting a step on both sides of the lower boards to help you up and over when needed. And it would take a lot longer for any water which ingressed prior to your noticing it, to start having really bad effects.

So with the above in mind as 'pre-thought', what came to me this AM was an idea that could be used on a boat like mine which has a very large, unbulkheaded main cabin area. What is needed is some sort of removable, yet fairly easily mountable (perhaps - or probably - in the dark, while sloshing about in a storm), bulkhead.

Put this in the "would probably work, but I may never have the time to try/implement the idea" file. At this point in time it is a thought experiment only. :)

How about creating an easy-up/down "bulkhead" from that heavy duty, vinyl-impregnated canvas material, like is used on billboards, heavy waterproof bags, or even dinghy fabric?
Use an extra large, heavy duty maybe even waterproof zipper, one half of it capable of being mounted to the interior of the boat, the other to a shape of this fabric that will create a temporary "bulkhead" across the boat?
Even if the zipper wasn't waterproof, it could have flaps which should slow the water flow to a point where it is much easier handled. It needn't be sealed to the overhead, even - just having it there chest-high, even if water could spill over it to a degree, it would still serve as a baffle to help slow/stop sloshing. You could mount one-way valves into the fabric, of a size to accept a hose from your bilge pump, or a dedicated secondary/temporary pump, for draining just this 'compartment'...
You could locate it at strategic points, the narrow passage between the headboards of salon and settee, for instance. If you have two of them, set a third 'wall' between the two which runs for and aft to baffle side-to-side water movement.
Set up and only halfway zipped would allow you easy movement about the interior, yet also allow you to create a 'flood compartment' in seconds.
You might be able to get rid of the coffer dam boards, and just use this fabric in a bulkhead opening, as it would be as easily 'mounted' yet stow in a smaller space...

I dunno, but there might be some 'good' in this idea. Not yet ready for SharkTank, though... ;D

[Owly055]

I don't believe a fabric system of any kind will realistically withstand the pressure involved in trying to keep water confined to one area of the boat, the pressure is going to be considerable, and the problem of attaching fabric securely and water tight is a big one.   Liners for all intents and purposes doom a holed boat, by providing a conduit for water between the hull and liner no matter what you do to try to stop it.  The chances of saving a boat with a liner that has a hole below waterline are almost zip if you are at sea...... It's going to sink and there isn't much you can do about it.   There are some logical places to separate off from the rest of the boat due to greater vulnerability.   Everything in the bow area that can be sealed from the rest of the boat should be.    The chain locker, and the space beneath the V berth would be a good start.   The bilge is a natural pathway in one of the more vulnerable areas, and could be divided into sections, each with a water tight lid.  They may not provide flotation, but they can provide isolation.   The head, hanging and hanging locker that are typically opposite and toward the bow could be made sealable, as could the opening from the saloon to them, but again liners make this nearly impossible.   Likewise the storage areas beneath the berths in the main cabin / saloon and other storage areas could be designed to be sealed.  If you get a hole punched in the hull, it is liable to be in the fore quarter of the boat close to the bow, so this area needs to be a priority.  If for example something punches a hole through the hull in the head area, you have a confined area which could contain the water, and as you previously said, a "step over" door sill could contain water long enough to allow you to seal things up.   The most logical divisions are forward and aft of the saloon.   A water retaining partition here could isolate a large part of the boat.  Engine compartment, lazarette and cockpit lockers are all logical divisions.   The cockpit lockers lie in the waterline area where if dismasted, your mast might pound a hole in the hull, the only interior space that can be easily isolated that does.  A quarter berth of course is in this area also if there is one.   
      In a boat without liners, there are many options.......... in a boat with liners, virtually none.   

                                             H.W.

Food for thought/speculation: I've thought a lot about this topic over the years, and will likely continue to do so my entire life, as I intend to live on a boat until they throw me off of it to feed the crabs. :) I had a brain flash while thinking on it again this AM. Current boat, the Islander 36, in its current OEM state, is a typical example of the type of fiberglass boat which could be deadly to get holed while at sea, because cabinetry built into the liner makes the hull inaccessible in an easy-ish manner over probably 50% of the boat.

Yet for the sake of pure survival, I don't believe that you need to be able to immediately fix a holing, or that that in fact is even your top priority!
What is, is this: you must control the amount and location of a catastrophic flooding, prior to being able to stop it.
In this, compartments are the key - if you can mostly keep the water confined to 1/3 or 1/4 or less of the interior area in the boat, then your problems are going to be MUCH easier to deal with.

In order to see this in the real world, I suggest this as an "experiencement", so you'll have an idea of what you might be dealing with:
Get a dinghy which has positive flotation, take it out on a good choppy day and fill it up with water, and climb in (if you can! You might better fill it with you already in). What you'll find is that when you have a large volume of water able to roam at will within the confines of a hull, even one as small as a dinghy, it becomes extremely tippy and uncontrollable, and even with positive flotation, will roll such that bailing out to a point of getting everything dry again will have to wait until the sea state is such that it is basically calm.
Otherwise, that water in the boat constantly rolls the gunnel or stern or even bow under water, shipping more than you've been able to bail since the last time it scooped up a load. Scale that up to a 25'+ footer with positive flotation, decks nearly awash but still able to float, and you literally have *tons* of water rushing about inside your boat with every movement of the ocean outside, even if you have managed to stop the sinking.
Seriously - try this in a dinghy - you'll get a whole new appreciation for what it would probably be like to have a boat mostly filled with water out on a heaving sea. Trust me, I know (by doing the above in a sort of "accidental experiment"... ;D ).

So - compartments. Places where you can contain and thus control the water taken in. If you have a watertight anchor locker, and your cockpit lockers/lazarette are likewise sealed from the rest of the boat, that might be 15-25% of your boat sink-proofed already, leaving only the cabin space to deal with.
For this, the Navy uses bulkheads and watertight hatches, and while that works fine for ships and subs, it will take up a lot of space in a sailFar boat, as well as being heavy and expensive.

Much easier to implement would be 'slat board coffer dams' that could be inserted into a framework at your current bulkhead openings. If the bulkhead is well-sealed to the hull, then these boards would be able to keep the water confined to the holed area of the boat, whether that is the fore, middle, or aft. Put some gasket material on their top and bottom edges so they can seal against themselves, lash them down, and you are probably one-third or halfway done towards fixing your emergency.
In fact, if you were set up this way, it might even be smart while at sea to leave all your bulkhead openings halfway 'dammed', say up to a step-over height. It would make it a little inconvenient when moving fore and aft through the boat, but you could mitigate this by putting a step on both sides of the lower boards to help you up and over when needed. And it would take a lot longer for any water which ingressed prior to your noticing it, to start having really bad effects.

So with the above in mind as 'pre-thought', what came to me this AM was an idea that could be used on a boat like mine which has a very large, unbulkheaded main cabin area. What is needed is some sort of removable, yet fairly easily mountable (perhaps - or probably - in the dark, while sloshing about in a storm), bulkhead.

Put this in the "would probably work, but I may never have the time to try/implement the idea" file. At this point in time it is a thought experiment only. :)

How about creating an easy-up/down "bulkhead" from that heavy duty, vinyl-impregnated canvas material, like is used on billboards, heavy waterproof bags, or even dinghy fabric?
Use an extra large, heavy duty maybe even waterproof zipper, one half of it capable of being mounted to the interior of the boat, the other to a shape of this fabric that will create a temporary "bulkhead" across the boat?
Even if the zipper wasn't waterproof, it could have flaps which should slow the water flow to a point where it is much easier handled. It needn't be sealed to the overhead, even - just having it there chest-high, even if water could spill over it to a degree, it would still serve as a baffle to help slow/stop sloshing. You could mount one-way valves into the fabric, of a size to accept a hose from your bilge pump, or a dedicated secondary/temporary pump, for draining just this 'compartment'...
You could locate it at strategic points, the narrow passage between the headboards of salon and settee, for instance. If you have two of them, set a third 'wall' between the two which runs for and aft to baffle side-to-side water movement.
Set up and only halfway zipped would allow you easy movement about the interior, yet also allow you to create a 'flood compartment' in seconds.
You might be able to get rid of the coffer dam boards, and just use this fabric in a bulkhead opening, as it would be as easily 'mounted' yet stow in a smaller space...

I dunno, but there might be some 'good' in this idea. Not yet ready for SharkTank, though... ;D

[CapnK]

This is what I remember as a kid hearing on the motivational tapes Dad played being called "Possibility Thinking". :)

It goes without saying that one would need to bond liner to hull at the areas which are being 'compartmented'. Small walls could be added as well, in order to bridge gaps 'twixt liner and hull with the ultimate goal of making leaks stay in small spaces...?

WRT the ability of a fabric being able to withstand the forces of water, or not - I would bet that if a parachute, being made of the extremely flimsy cloth of which they are made, can yank a tank out of the back of an airplane at ~100 kts or so and then support it until it lands, then a fabric 'wall' could be engineered to withstand the force of even a few tons of water sloshing a few feet. :) That brings to mind a sea anchor, the 'chute kind - they get placed under such stress.
A heavy canvas-based material, reinforced with sewn-on strapping, would probably do the trick inside theboat. The cover flap over the zipper could be reinforced with snaps or Lift-A-Dot fasteners helping to relieve strains there. I was thinking of a erimeter zipper before, but one vertical in the middle would probably be easier to reinforce.

Mounting it to the hull/liner/cabinetry would probably be the weakest point. I would probably put a beaded welt on the fabric, and then use awning rail screwed and glued to mount that to. On my boat, putting that in the opening to the v-berth, and then on the after side of the head compartment would give me a 3' or so reservoir between the two. Another, placed between the forward end of the galley, and the same at the nav station, would section my salon area almost in half.

Also possible is to remove the entire liner from the v-berth area (I don't like that setup anyway), and before building back in, mount fabric like above so that a loose, sectioned 'bag' covers the hull interior, deck to keel. A puncture in the hull might not breach the bag material, and so it would contain the few gallons it could hold. If the fabric was compromised it would probably be a much smaller hole than what is in the hull, and so make flooding slower, and be possibly easier to get an emergency repair into place. Pull the slack off to one side so that the holes are no longer aligned, and screw the fabric right into the hull maybe...

Stretchy fabric over a few inches of EPS?