If your sailboat swamped, would it sink?

[Sail123]

I had a Mac 25, and in every out of the way place, everywhere was crammed with blocks of Styrofoam. In tests, Macs float, rather than sink, because of this safety feature.

On my recently acquired Clipper Marine, when I look into holds, dark foreboding places, all I see is nothing but darkness.

I am not big on the fact that someday, in a moment of bad weather, bad luck, or whatever, and the water comes rushing in, all the air goes rushing out, and down she goes.

Lets say I started saving water bottles. All shapes and sizes. These would go into the nooks and crannies on my Clipper Marine Aft Cabin Ketch. I figure it will take hundreds.

A gallon jug will float about 8 pounds of fiberglass. Lets say my boat has a weight on the water of 4000 pounds, that means I need 500 1 gallon plastic bottles to keep her at the top of the lake, swamped. I do not have room for 500 one gallon jugs. Doubt I could hide 100 of them inside. Does that mean I can do nothing to float her swamped? Would stowing away as many empty jugs as I can, help, or do nothing?

 

[RichH]

Dont waste your time. With that size boat if it starts to sink all those empty water bottles will force the deck to separate from hull .... and you'll be charged with dumping water bottle trash into the water.

Better to do due diligence on bilge pumps, intact seacocks & double clamped hoses, good locks on all the hatches, and a stout companionway (which is closed up in 'snot' weather) ... so if the boat does get laid over flat on her beam ends, she doesn't 'down-flood' through the open companionway or through an unlocked and 'surprise opened' locker, etc. etc.

When its 'bad' out, you lock and 'dog' everything down, including the companionway ... keeping the water 'on the outside' instead of letting it go inside is the best way to stay on top of the water.

;-)

 

[centerline]

a 4000lb boat would need about 65 cubic ft of displacement to keep it afloat, depending on how much gear you had on board. water bottles would work but for the effort and space involved along with the longevity, I wouldnt trust them to keep me safe.... styrofoam is a better option
if the deck and the hull are properly fastened, you will tear the boat all to hell in other spots before it seperates at the seam...... for any reason. a single #10 stainless fastner has a tensile strength of about 18,000lbs, and the shear strength used in the manner that it would be to join the hull, liner and deck, is around 550-600 lbs. each. the fiberglass is probably a bit weaker but not by much. (although, aluminum pop rivits are way less, they are still about 6- 8 inches apart all around the joint.... more than strong enough)
but i do strongly agree that an ounce of prevention is worth 10 pounds of cure.... dont let the water in to begin with.

 

[jibes138]

I have seen in the past an inflatable bladder you can get if you are really concerned. They use these in the salvage business to refloat boats that sink. You will need a way to inflate it but perhaps a scuba tank or two would take care of that problem very quickly and without electricity for a pump.

 

[RECESS]

At 14,000 lbs, my boat would sink like a rock!

 

[Ross]

If your boat is ballasted it will sink if adequately flooded. It will however be self righting which will limit the time period available for flooding. With all of the hatches closed most keel boats will survive a complete rollover but will probably have damage to the rigging.

 

[RAD]

Just get enough insurance and go sailing.......don't worry sometimes shit happens and sometimes it don't

 

[31seahorse]

Hello Members,
Very interesting discussion. I like the ideas for avoiding the "fill up" in the first place.

Questions: (1) In the first picture are the men on the cabin top standing there to keep the hull and deck from seperating? (2) Do you remember the old ads for Boston Whalers in which the hull was cut into 3 pieces and each floated? I don't remember whether there was a crew member on each piece. (3) Would you store the empty soda bottles or the gallon jugs as each became available or would you wait until you had enough to fill all the empty space? (4) If you crammed all the empty spaces with empty bottles where would you keep the full bottles of beer?

OK, enough dumb questions. Our Celebrity daysailer has rectangular blocks of styrofoam tabbed into each side of the bow and stern compartments. Because of that I have considered adding similar blocks of foam (from packaging materials) into the open hull areas of our Precision 18. I haven't done that yet, but this discussion has given me opposing views on the project.

Thanks, Phil

 

[Ross]

A 4000 pound fiberglass boat will not require 70 cubic feet of floataton because the specific gravity of FRP has to be considered. My boat has about 3000 pounds of lead and 400 to 500 pounds of other metals and about 600 pounds of wood. The rest is a composite of glass fiber and polyester resin. Nylon rope just barely sinks so it doesn't require much help to float.

 

[Warren Milberg]

RichH has the right idea: water out/dry in. If my boat flooded and sank, I would not want to salvage it. "Hello, BoatUS, you'll never guess what happened to my boat today....."

 

[njwtech]

My boat weighs 7500 lbs and already has little enough storage. I couldn't put enough bottles on board to keep it afloat. Gary, it sounds like we have transitioned to the size of boat where we have to use skill to keep it afloat instead of luck

(I just realized - maybe the foam in the Mac was like "training wheels"...)

 

[Gary_H]

Would mine sink...like a stone. There might be enough empty Rum bottles on board to keep her afloat..I don't know.

 

[FastOlson]

Being "positive" about floating

Whoa everyone.... step away from the displacement/ballast points and relax....

Consider how much of your boat, at rest, lies beneath the waterline. Physically, not very much I would guess.

i.e. if you could cut it all off (!) right above the present waterline like a sort of lower-hull-shaped dish it would continue to float just fine. Quite a bit higher, actually, with the topside and rig weight suddenly removed.

Adding enough floatation to achieve positive bouyancy when flooded does remove some valuable storage space, but not where you will ever notice when looking around the interior. Heck, if you make a foam-core hull thicker - like a couple inches - that might do the job just as well. The Holman-designed FD-12 has this feature.
There was a European Builder, Etap, that made their whole line of sailboats unsinkable.

In the 70's and 80's, Ranger Boats in Washington build hundreds of Ranger 20's and Ranger 24's with positive floatation. I even obseved an R-20 fully flooded one windy evening on the Columbia River when the two young (and rather drunk) guys sailing it decided to test the theory by repeatedly taking knock-downs with the genny up until they flooded the interior. Since they could not pump it out due to lacking a good pump or two functioning brains, the sherrif towed them in to a dock.


So type of ballast, like the lead keels in the models I referenced, is not the point. Only thing is to have enough trapped air, equal to the immersed hull form interior volume, right up to the waterline.

LB

ps: Yes, our present boat would indeed sink if flooded all the way down.

 

[RECESS]

Yes, but the question was if it was already swamped, ie filled with water. Or another way to look at it, is your boat positively buoyant?

 

[inarathree]

Wasnt it back in August that the 100' Rampler capsized? I am sure being a racing boat, and stripped of ever last bit of weight, there wasnt any bottles, jugs or foam, and it seemed to stay afloat, even upside down. I know that the Open 40, 50, 60's all go through a test where they are rolled over for self righting. If you want your PHRF rating, you must be prepared to prove your boat will right itself if laid over.

Having said that, what do you mean by swamped? just the cockpit, or the whole cabin? i have seen quite a few boats, sail and motor, that were pretty swamped, but still had enough of a pocket of air to keep them afloat... barely. I have also seen several go right to the bottom, but those usually have big holes in them.

 

[Benny17441]

Your Clipper Marine 32 may likely be safer than the Mac 25. First of all the Mac 25 will capsize in conditions that may be adequately safe for the Clipper and second the hull of the smaller boat will fill up with water a lot faster than that of the larger boat. Having time to repair and pump water out may make all the difference. Larger boats are usually equipped with a high volume emergency gusher pump and may likely carry a dinghy. That is a nice picture of the Mac at dockside, I do wonder how it will behave in breaking waves. Don't short change the 32'.

 

[Sail123]

Thanks for the upside comments on the CM 32. I will not go out in heavy winds, and I hope to not run her into the rocks, but the idea of a floating boat, always, is not a bad thing. Currently, she only has a manual bilge pump. I plan on changing that real soon to an automatic pump.

The posts in this thread where folks point out their yachts would sink like a stone, swamped, is a wake up call in some ways. The training wheels comment was also a good one.

The bottles stuffed inside the boat was not an original idea, I saw someone post about it years ago, on another forum, and I wondered if it would even do anything. I do not think it would keep a typical sailboat afloat given the stuff we tend to put in our boats.

Blue hull is in the slip, waiting to get pulled and put up for sale and the Aft Cabin is in the diesel shop waiting on an exhaust gasket, to be splashed soon.

The spot of light blue? That may be the original color hiding under the oxidation. Gets wet sanded and polished after the diesel shop.

Back on topic, all thru hulls have been replaced with bronze and all hoses look good, and I will double hose clamp them.

Every time I go out to the marina, I half expect to see the blue hull full of water. She is doing good! When we splashed her, a hose was off, and in no time, she was holding 6" of water on the cabin floor. We found the leak, and pumped her out. I will not be so quick to take the Aft Cabin sailboat off the trailer when we back her in the water. Will look all over inside first, and pull her back out at any sign of a leak.

Your Clipper Marine 32 may likely be safer than the Mac 25. First of all the Mac 25 will capsize in conditions that may be adequately safe for the Clipper and second the hull of the smaller boat will fill up with water a lot faster than that of the larger boat. Having time to repair and pump water out may make all the difference. Larger boats are usually equipped with a high volume emergency gusher pump and may likely carry a dinghy. That is a nice picture of the Mac at dockside, I do wonder how it will behave in breaking waves. Don't short change the 32'.

 

[jibes138]

every boat inserted into water immediately sinks until it displaces an amount of water equal to its' weight. So what you need to do is make sure your boat will displace an equal amount of water to its' weight when it is leaking badly. Rather than the soda bottle idea why not just use FRP to encapsulate some of your storage areas. if you completely seal up the v-berth for instance and install a watertight door. This is what the racing boats do to make sure they don't sink when capsized in the southern ocean. Closing the companionway will slow ingress of water but no companionway is leak tight that I know of on a production boat so it will slowly fill up and sink.

 

[centerline]

A 4000 pound fiberglass boat will not require 70 cubic feet of floataton because the specific gravity of FRP has to be considered. My boat has about 3000 pounds of lead and 400 to 500 pounds of other metals and about 600 pounds of wood. The rest is a composite of glass fiber and polyester resin. Nylon rope just barely sinks so it doesn't require much help to float.

you are correct.... it can all be figured out perfectly if you know the weights and composites of all the materials that are included on and in the boat, but in general 70cf of styrofoam is a close, safe number for a 4000 lb boat. in my humble opinion I would rather have 300 pounds too much flotation than one pound too little.

 

[robertsapp]

It is important to remember that the laws of physics state that every boat continually seeks its point of maximum stability. On a catamaran, this would be floating upside down on the surface. On a keel boat, this would be sitting right side up on the sea floor. In a water balllasted boat full of floatation foam, it is decks awash. Our job as Captain is to continually frustrate the boat in its relentless desire to achieve this state.