Built in bouyancy/flotation
- Thread starter greg_m
- Start date
Many have considered it. Then rejected it because, given the weight of the boast, the amount of flotation material required would exceed the space available to put it out of site, to say nothing of eliminating all storage areas. [former C22 and C25 owner]
Not many bigger boats have it and I don't see why a C22 would "really" need it.
That assumes you use a boat in the conditions it is designed for, and are competent with it.
Looking at a discussion thread on the web, I found a calculation that you would need a 25 cubic feet of foam to have a 3500lb boat float just at the surface, with an additional 8 cubic feet if you wanted it to float high enough to have the deck out of the water.
http://forums.iboats.com/forum/boat...tions-or-what-will-it-take-to-float-your-boat
FWIW: Since you usually need a raft/rib to get to shore anyhow, I simply got one of those. I plan to tow it, inflated, if there is a risk of no quick rescue if things go wrong.
On the lake where we normally sail, a smoke flare, and our life jackets will solve issue. On a busy weekend the risk would be not getting run over by an idiot in a ski boat or jet ski, not the risk of drowning or hypothermia.
Coastal sailing is another matter.
What a lot of people don't calculate is that it is more or less the the air in the cabin that keeps the boat afloat. (An equivalent volume of air weighs less than an equal volume of water). If you fill up an area that is normally air with foam, you actually increase the weight of the boat and decrease the amount of air it can hold, which makes it less buoyant. The only time foam is good is if you can use it to displace water, or keep water out. By itself, its not inherently buoyant, its the entrained air within foam that makes it buoyant, and you already have enough air in the cabin of the boat.
Mike
LOLIf the boat is sinking, 2 options inflate the life raft in the cabin and save the boat Or inflate the life raft , climb in it and see what happens to the boat.
I'm guessing that recovery costs, even with the boat awash, may likely exceed the value of a C22, depending on where the boat is. A lot of things related to boats, seems needlessly expensive.
2010 thread:
https://forums.sailboatowners.com/index.php?threads/that-sinking-feeling.119310/
In reading one of the C-22 sinking stories, I saw this great note at the end, which seems to truly exemplify the sailing if not the entire boating community:
"Publisher’s Note: Sailing incidents bring out all sorts of village opinions. There will be lots of “they should of…”, but the best comment heard thus far came from Charlie Overcash, who simply said “That could of been me.” This writer indeed has accomplished some impressive boating mishaps over the years, fortunately beyond the sight of town. Combine a jammed sheet for a few seconds and the right instant gust, and that could be any of us."
https://forums.sailboatowners.com/index.php?threads/that-sinking-feeling.119310/
In reading one of the C-22 sinking stories, I saw this great note at the end, which seems to truly exemplify the sailing if not the entire boating community:
"Publisher’s Note: Sailing incidents bring out all sorts of village opinions. There will be lots of “they should of…”, but the best comment heard thus far came from Charlie Overcash, who simply said “That could of been me.” This writer indeed has accomplished some impressive boating mishaps over the years, fortunately beyond the sight of town. Combine a jammed sheet for a few seconds and the right instant gust, and that could be any of us."
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Most of the "away from the dock" sinking incidents I've read of with a C22, seem to be due to hatch being open, and cockpit locker covers being unsecured in a knockdown.
As that "sinking feeling" thread says, "Very few keel boats are 'unsinkable'"
You don't see people asking "how much foam should I put in my "47' Pilothouse Blah", but the C22 seems, very often, to be used as a beginners boat. I suspect that's why this question seems to come up more often.
The way you minimize the risk in anything, is to develop your skill, which means anticipating problems (both on the water, and with gear), and dealing with them before they actually become a problem.
That said, there are people out there who push the design use of their boats. Both sailing skill, and well chosen boat upgrades/gear, become much more important then.
There's a guy who sails a C22 in Patagonia for example.
@greg_m Where/how do you use your boat ?
As that "sinking feeling" thread says, "Very few keel boats are 'unsinkable'"
You don't see people asking "how much foam should I put in my "47' Pilothouse Blah", but the C22 seems, very often, to be used as a beginners boat. I suspect that's why this question seems to come up more often.
The way you minimize the risk in anything, is to develop your skill, which means anticipating problems (both on the water, and with gear), and dealing with them before they actually become a problem.
That said, there are people out there who push the design use of their boats. Both sailing skill, and well chosen boat upgrades/gear, become much more important then.
There's a guy who sails a C22 in Patagonia for example.
@greg_m Where/how do you use your boat ?
Some of the links in the thread that @Sacto Dave posted are dead.
Here's the same links via the Wayback Machine over @ archive.org:
https://web.archive.org/web/2007082...y/Rescues/1992/7_12_92_morf_lake_michigan.asp
https://web.archive.org/web/2007081...na22fleet58.org/Learning_Center/lc990302.html
Here's the same links via the Wayback Machine over @ archive.org:
https://web.archive.org/web/2007082...y/Rescues/1992/7_12_92_morf_lake_michigan.asp
https://web.archive.org/web/2007081...na22fleet58.org/Learning_Center/lc990302.html
@Leeward Rail - thank you for finding those! What a story! If I were 't falling asleep, I'd read that very detailed story of Moonraker. Tomorrow!
Night!
Night!
Hi All
Wow thanks for all responses and links. I will spend some time reading them. This is my first trailer sailer and my first attempts at offshore sailing owning my own boat. Lots of lake and inland dams experience. Oh and about 13 years on vessels of around 35000GT upwards to around 50000GT... but then we had nearly 85000HP to argue with the weather!
One of my subjects I studied to be a marine engineering was "Naval Architecture" and we spend most of that course doing stability calculations and damage/flooding scenario calculations, reserve bouyancy and so on... so the calculations is not the issue. I have worked out that my boat will need around 1,5 cubic meters of polyurethane foam to stay afloat to be a life raft.
Storage space seem to come up in terms of a "why not". After crawling through the entire hull, re-lamintaing the entire deck and relaminating the entire transom I am very familiar with all the spaces available to install floatation and then still have space for storage. My reply question to that would be: "What the hell do you store that needs such a large volume?" Taking a 10-day trip into a Namibian desert in a 4x4 vehicle has taught me that space is premium and you pack only what it needs to survive comfortable = not live like a king. There is no watering holes, no convenience stores and no fuel refilling stations along the way and the only comm's is a satellite phone! There are also massive "waves" in the desert but they are a bit sandy!
What am I going to use the boat for: I actually will be sailing out of False Bay in the south of Southern Africa, Simons Town being my home base. Day trips, with occasional over-nighter mostly to start with is the intention. I'm very aware of the limitations of the boat structure, swing keel pro's and con's etc. so not trying to turn the boat into what it's not = a blue water cruiser. However even the best weather reports go wrong and the swell/chop and wind can pick up very quickly in the bay.
Boat structure: I have strengthened the deck support structure, doubled the deck support in way of the fore and aft shrouds, taken the forestay load down into the bow, the aft stays loads down into the transom and one thing my boat was built with was the upper shrouds have metal tabs built into the bilge spaces with metal flat bar linking then tabs to the deck fittings. PO also went for stainless, 6mm rigging alround.
Local regulations: A life boat/life raft is required if you plan to go more than 15 NM offshore... unless the boat has sufficient built in bouyancy to make it float! That in itself is my motivation for exploring this option. Just crossing the bay to another club on the opposite shore takes you more than 15NM offshore. Sailing further afield up the West Coast of Southern Africa is doable but there is no real safe anchoring grounds around most of our coastline.
To me, trying to squeeze in 1 and 1/2 cubic meters of foam seems really easy with the vast space available in the boat. As to air floatation = thats only as good as the leak that lets the air out while you watch the boat sink! Foam is way more space convenient than plastic bottles.
Wow thanks for all responses and links. I will spend some time reading them. This is my first trailer sailer and my first attempts at offshore sailing owning my own boat. Lots of lake and inland dams experience. Oh and about 13 years on vessels of around 35000GT upwards to around 50000GT... but then we had nearly 85000HP to argue with the weather!
One of my subjects I studied to be a marine engineering was "Naval Architecture" and we spend most of that course doing stability calculations and damage/flooding scenario calculations, reserve bouyancy and so on... so the calculations is not the issue. I have worked out that my boat will need around 1,5 cubic meters of polyurethane foam to stay afloat to be a life raft.
Storage space seem to come up in terms of a "why not". After crawling through the entire hull, re-lamintaing the entire deck and relaminating the entire transom I am very familiar with all the spaces available to install floatation and then still have space for storage. My reply question to that would be: "What the hell do you store that needs such a large volume?" Taking a 10-day trip into a Namibian desert in a 4x4 vehicle has taught me that space is premium and you pack only what it needs to survive comfortable = not live like a king. There is no watering holes, no convenience stores and no fuel refilling stations along the way and the only comm's is a satellite phone! There are also massive "waves" in the desert but they are a bit sandy!
What am I going to use the boat for: I actually will be sailing out of False Bay in the south of Southern Africa, Simons Town being my home base. Day trips, with occasional over-nighter mostly to start with is the intention. I'm very aware of the limitations of the boat structure, swing keel pro's and con's etc. so not trying to turn the boat into what it's not = a blue water cruiser. However even the best weather reports go wrong and the swell/chop and wind can pick up very quickly in the bay.
Boat structure: I have strengthened the deck support structure, doubled the deck support in way of the fore and aft shrouds, taken the forestay load down into the bow, the aft stays loads down into the transom and one thing my boat was built with was the upper shrouds have metal tabs built into the bilge spaces with metal flat bar linking then tabs to the deck fittings. PO also went for stainless, 6mm rigging alround.
Local regulations: A life boat/life raft is required if you plan to go more than 15 NM offshore... unless the boat has sufficient built in bouyancy to make it float! That in itself is my motivation for exploring this option. Just crossing the bay to another club on the opposite shore takes you more than 15NM offshore. Sailing further afield up the West Coast of Southern Africa is doable but there is no real safe anchoring grounds around most of our coastline.
To me, trying to squeeze in 1 and 1/2 cubic meters of foam seems really easy with the vast space available in the boat. As to air floatation = thats only as good as the leak that lets the air out while you watch the boat sink! Foam is way more space convenient than plastic bottles.
Lotsa lessons there in that Moonraker story, thx for that!!
mmm... there's always one!Hmmm....I thought this was going to be a bikini thread.
Something I wondered about was the wooden bung fitted into the top of the flexible pipe secured with a pipe clamp with a hole barely big enough for the lifting keel cable to pass through... reading about air venting from the keel lifting pipe I now understand and will make sure it goes back with the new guide ball and pin!
My boat is not fitted with any sort of keel locking screw... but is it actually a practical solution?
wooden bung, never saw or heard of that one, maybe a Jaguar thing or PO mod...makes some sense though...
keel lockdown bolt....plenty debate on that here and elsewhere as to it's usefulness/pros-cons...not enough holding power there in the event of a turtle to keep the keel from dropping back into the trunk imo, supposed to help with keel wobble/thunk some though.
Cockpit lockers are absolutely #1. Moonraker is a prime example. Leave them unlocked at your peril. They are the first place a C22 will ship water when she is on her side. Forward hatch and companionway come next ... and I hope we don't need to mention not to sail under an open poptop.
I have a thick rubber cap clamped on my volcano tube, same concept as the wooden bung. God forbid we ever turtled, but a lot less air would exit the hull through the tube. It's a one-time, $5 investment that could conceivably save the vessel. New Design owners should also make a habit of keeping the sink drain stopped.
I'm not one to ever use flotation, but if anyone wants to and it gives them peace of mind ... hey, it's your boat, have at it! Likewise, I have no use for a keel lockdown bolt. I have zero faith it will ever help me and, me being me, I know I will forget to loosen it, thereby gouging the keel, bending the bolt and possibly damaging the trunk.
I never saw that pic of Bilbo's before! I'm going to repost it here, along with another one that popped up not long ago. It is gratifying to see how much a C22 can take and NOT sink, even with an open companionway!
I have a thick rubber cap clamped on my volcano tube, same concept as the wooden bung. God forbid we ever turtled, but a lot less air would exit the hull through the tube. It's a one-time, $5 investment that could conceivably save the vessel. New Design owners should also make a habit of keeping the sink drain stopped.
I'm not one to ever use flotation, but if anyone wants to and it gives them peace of mind ... hey, it's your boat, have at it! Likewise, I have no use for a keel lockdown bolt. I have zero faith it will ever help me and, me being me, I know I will forget to loosen it, thereby gouging the keel, bending the bolt and possibly damaging the trunk.
I never saw that pic of Bilbo's before! I'm going to repost it here, along with another one that popped up not long ago. It is gratifying to see how much a C22 can take and NOT sink, even with an open companionway!