There has been a fair bit of discussion about the sinking of the Sonoma 30 Cowabunga off Hawaii, and below is the story from Mike Hanson who was one of the crew during this harrowing incident. There are many lessons to be learned here...
It was a half hour past midnight when we noticed the boat was filling up. We had heard water sloshing around in the cabin, and when we shined our flashlights below, it was already about eighteen inches deep. We fumbled for a few minutes trying to manually remove the water with the hand-operated bilge pump, but we soon realized this was no ordinary leak. It was blowing 18 knots with five foot seas in the middle of the Kauai channel, and our ship was sinking.
funny thing about the hose clamps: i have removed hoses from thru hulls and can assure you that it is not an easy task. sometimes the hose must be cut just to get it off the bronze fitting. more often it must be muscled off with great strength. the odds of one of those hoses coming off by itself? remote to impossible
__________________
some of the best times of my life were spent on a boat. it just took a long time to realize it.
Unfortunately Gord's results appear to include your average water skier.... probably way off for sailing cruisers ...
The BoatUS statistics (not Gord's), are the results ofall their insurance claims, which will almost certainly represent a preponderance of small power boats.
Nonetheless, they are (or should be) very instructive to our cruising membership.
__________________
Gord May "If you didn't have the time or money to do it right in the first place, when will you get the time/$ to fix it?"
When I was sailing on the 88 foot schooner Ocean Star a number of years ago there were always two of us on watch during the night. One of those people had to do a "boat check" every hour. They would walk through all the compartments
including the engine room with a flashlight checking for something amiss. Including checking the bilge. Seems like a good practice on any boat.
funny thing about the hose clamps: i have removed hoses from thru hulls and can assure you that it is not an easy task. sometimes the hose must be cut just to get it off the bronze fitting. more often it must be muscled off with great strength. the odds of one of those hoses coming off by itself? remote to impossible
Yeah but it seems those are the really old dried out hoses that are about to crack and fail. New ones go on and off easy - Maybe we shouldn't replace old hoses? - LOL
Case A) water gets in thru somewhere where you have no access and overwhelms the pump(s)' capacity.
You would be shell shocked how low pump capacity is on some very posh, very desired, EU made, boats.
The same applies to access on the mentioned design.
The same applies to many owners having NO clue where things in their boats are located (e.g. seacocks, pumps) nor how to use them.
Case B) you hit something and you can see how fast water is getting in.
No way pumps can manage. Start the engine, start the pumps, try to stop the leak, activate EPIRB, get the liferaft, water supplies, dry bag with handheld VHF and flares ready ... try to stop the leak, make sure EPIRB is transmitting ...
Case C) the boat starts taking water at the dock and nobody notices, say at night.
I believe case C) is the most common (witnessed two in last 10 years).
I have worked on HUNDREDS of boats for 43 years, and other than my own, which I built, never seen such a "safe" boat. ALL production boats, even high end ones like Caliber & Pacific Seacraft, use cheap hose clamps, rather than all 316SS AWABs. It baffles me. What are they thinking?
They regularly put mediocre hoses where you can't even get close enough to the end to see them directly, much less a close inspection. You can't tell much in looking for micro cracks, from 3' away, with a swivel mirror.
Production boats are built down to a price, and NO regard is given to the guy like me, who later works on them.
PS boats, for example, mount the head to the pan before mounting the pan into the boat. You can't replace the head, because the nuts underneath are not captive. You have to drill a large inspection plate sized hole, just to hold the mounting nuts from spinning!!!
It just goes on and on. Every single piece in most production boats is put in there in a way that saves the buildermoney, and simplifies construction. To hell with ownership later.
FAR less than 1% of all boats built, ever go out of sight of land, so they assume that to be the case.
High end boats go out of business first, more often than not. People want quality, but won't pay for it. It is usually the "pretty good, but for a REALLY good price" boat companies, that survive for decades.
If I ever switch from my self built (litterally unsinkable) trimaran, to a production monohull, I would re-wire and re-plumb it from stem to stern. Then I would rely on just ONE good seacock and a manifold to supply the other needs.
Then I would watch everything like a hawk!
I find leaks & "sinkings about to happen", all of the time...
I so agree on your comment regarding a manifold, just never seen the point in cutting many holes in the hull when one would suffice.
When we bought our 440 i went through it with a fine tooth comb, a really disturbing situation involves the forward lockers port and starboard of the main one (AT MAST BASE) , they are all interconnected with limber holes to simplify draineage.
Most 440's use either the port or stb ones for fuelstorage for their dinghy as the previous owner did as well, now in the central locker there is the freshwater pump, watermaker, anchorwinch and chilled water air con all happily operating with relays, switches and circuits sparking in an explosive atmosphere.
How many boats have just this same scenario waiting to go BANG??
It is the aftermarket installers who are the greatest worry.....
__________________
"Political correctness is a creeping sickness that knows no boundaries"
And there is just plain old stupidity or bravado - A bareboat charterer in the Virgin Islands thought it would be cute to "put the rail in the water" close hauled to show his buddies "how to really sail." Unfortunately, all the portholes and hatches were open at the time that the boat caught a gust and laid a spreader in the water (knock-down). Boat filled with water quickly and sank. It was recovered as it was only 40 ft deep in that area and they found the hatches and portholes open. I don't think the guy got his "security deposit" back.
Boat: Jon Sayer 1-off 46 ft fract rig sloop strip plank in W Red Cedar
Posts: 21,156
Re: sinking??????
Quote:
Originally Posted by micah719
I read a story once about a GRP boat sinking because someone left a bottle of nail-varnish remover (acetone) open in the heads compartment: it tipped over, leaked into the bildge, ate a hole in the hull and sank it. I'm fairly sure it was in a book by Peter Kemp.
This one smacks of pure urban legend status. Acetone will not dissolve cured polyester resin, epoxy or fibreglass.
OTOH, an acquaintance of mine had a boat sink at the dock (San Leandro CA marina) from an acetone spill. He had unwisely used Tygon (Clear, unreinforced PVC) hose for his cockpit drains. He failed to notice that while he had cleaned up the acetone that he saw on the cockpit sole, quite a lot must have gone into the drain where it sat and eventually destroyed the hose.
So, from all the stories above, it is clear that not only is a boat is a hole in the water into which you throw all your money, that hole wants to fill itself with water as well. Beware!
Cheers,
Jim
__________________
Jim and Ann s/v Insatiable II, lying Port Cygnet Tasmania once again.
Recently in the Malacca Straits, catamaran starts making water through stern tube, overwhelms pumps, floods engine room, shorts just about everything. New owner uses iPhone to get help from friends with powerboat who go to the rescue and connects massive AC submersible pump to keep afloat and tow 40NM to Singapore. That was a near miss, very near.
Small power boat goes out with 4 or 5 on board, takes water from a wave and becomes unstable. Whole thing under in nothing flat.
Only anecdotal, but seems within the parameters shown above.
__________________
Capn Morgan
'If you can fill the unforgiving minute with sixty seconds' worth of distance run...'
Recently in the Malacca Straits, catamaran starts making water through stern tube, overwhelms pumps, floods engine room, shorts just about everything. New owner uses iPhone to get help from friends with powerboat who go to the rescue and connects massive AC submersible pump to keep afloat and tow 40NM to Singapore. That was a near miss, very near.
Small power boat goes out with 4 or 5 on board, takes water from a wave and becomes unstable. Whole thing under in nothing flat.
Only anecdotal, but seems within the parameters shown above.
Interesting. I was thinking since I already have a Honda 2000 generator on board if it might be worth it to buy a 120 volt house sump pump as an emergency backup to the 12 volt bilge pump and manual gusher hand pump to buy some time in case of a BIG leak.
Speaking of big leaks here's some tips on what to do if it does happen while underway: THE BIANKA LOG BLOG: FIXING A HOLE
The volume of water that enters a boat is proportional to the square root of the depth of the hole and proportional to the square of the hole’s radius. That is, a hole twice as deep allows in 1.4 times more water, and a hole twice as large lets in four times more water.
Incoming gallons per minute = D x square root of H x 20
where
D = the diameter of the hole in inches
H = depth of the hole below outside water level*
Hence: A 3 inch diameter hole, 4 feet below the waterline will let in 120 gallons a minute, or 7,200 gallons an hour. (Mr. B's 3" hole would have to more than 4 ft. down)
Most boats don’t (cannot) have a bilge pump system which is large enough to keep up with a leak caused by hull damage. Bilge pumps are designed for small quantities of water, and are not damage control pumps.
* However, the flooding rate of a boat will slow down considerably when the water level rises above the leak. In this case, the “h” in the flooding formula becomes the difference in level between the water inside the hull and the water outside it. Additionally, any air in the cabin will provide back-pressure to further slow the flow.
__________________
Gord May "If you didn't have the time or money to do it right in the first place, when will you get the time/$ to fix it?"
I almost sunk my boat right after of got it. We had just taken possession and were making it ready for the trip down. We had no idea what was what on the boat and no one to tell us. While inspecting the hole where the bilge pump resides someone hit the cheap toggle switch from the auto position to man, so the pump came on and ran and ran until the cb for it popped. no one saw that either. (poor design all around I know) we didn't realize that there was also a hole some where in the line for the fresh water fill to the 500 gallon water tanks. so we were merrily filing the tanks and waiting for the water to come bubbling out the fill hole...and sort of forgot about it... about an hour later I happened to be looking in the engine room for stuff and noticed the water almost to the bottom of the oil pan! Not very far away from drowning the batteries! First thing I did right was go turn the water off! second was to get my buddy on the manual pump while I figured out just how I had almost ended my sailing adventure on the first night. Very soon I'll be direct wiring a back up pump to the battery. probably one that stays dry and will remove all the water from the bilge. The one I have now lets about 2 inches sit in there all the time.