Snow Loading

[loubennett]

On Monday night my neghbor's 40+ foot boat sunk at our dock due to snow loading from last weekend's storm. I had not fully considered the problem, but now when it snows the boat is the first priority, before the driveway and cars. I did a little investigation and analyzed the problem. Snow that falls at aroung 32 degrees has a 20% water content. As a point of reference, this means that 2 feet of new fallen snow over a 100 square foot area weighs over 5,000 lbs. For an Albin 28, it's like putting 25 to 30 adults in the cockpit. The boat floats significantly lower in the water. Now the question is "How low in the water becomes a problem?" The answer is a lot less than many may think. Even on a boat in good condition with all seacocks closed there are several flooding paths. One is the engine exhaust. On most modern power boats there is no high loop in the exhaust to prevent inflow of water. Basically if the muffler goes below the waterline, water will flow in through the engine. Another is the cockpit scuppers. If the cockpit sole gets below the waterline, water will flow in and soon after find a path to the bilge. A third is the sink drains. They usually have no seacocks since they drain above the normal waterline. If the sink gets below the waterline, water will flow in through the sink drain. These are all cacsading effects. As water enters, the boat sinks lower, the lowest path will start the process with additional paths contributing as the boat sinks lower. Most of our bilge pumps are insufficient to keep up with inflow and the boat ends up on the bottom in a short period of time.

The moral of the story is that even a well maintained boat that has been properly winterized can be sunk by the snow storms we have had this winter. If you store your boat in the water, put it high on the list of snow removal chores. Delaying snow removal from your driveway and cars will not result in a large insurance claim. Delaying snow removal from your boat can lead to a major incident.

[loubennett]

I went back and checked my calculations. The weight of 2 feet of wet snow over a 100 square foot area is approximately 2,500 lbs (half that in the above post). The 5,000 lbs was an approximate number for 2 feet of snow on an Albin 28 including cockpit, swim platform, pilot house roof, and foredech area. The conclusion is the same - snow loading can sink a boat well before most of us would think.

[loubennett]

Across the creek from my dock is an Albin 28 named Esperanza at a private pier. The location is at the head of Back Creek in Annapolis. The boat is heavily laden with snow and floating quite low in the water. The swim platform is nearly touching the water. If anyone knows the owner, please give him a call, he appears to be dangerously close to a major problem. The weather forecast is for another 4 to 5 inches of snow on Monday and that could be enough to cause a sinking.

[Carl]

Lou, I dont know the owner, but you can see the results of snow load on a flat roof covered slip marina. All of E dock came down on some very pricey boats, and all slips were full. I hope everyone had good insurance. Thirty-eight boats are sunk. There will be an environmental disaster with leaking fuel. The boats are really crushed and I doubt salvageable. Another problem is that the adjacent dock, the structure is leaning and may also go...they cannot get the boats out from under the leaning roof because of the ice in the river and the fact that they are all winterized. It's a real mess like I've never seen before. There's not much they can do right now. This all happened at the Bohemia Marina.
http://s45.photobucket.com/albums/f68/w ... 12%202010/

[loubennett]

Carl, thanks. I hadn't thought about the covered slip issue. Most of the covered docks I've seen are little more than sun shades. Either not designed to take the snow load or not maintained to that level. That's a real mess and inevitably there will be disputes between the boat's insurance company and the marina's insurance company about who is liable. That will only delay getting the owners back in operation.

[jcollins]

That is awful. Reminds me of Hurricane Isabel. It only happens once every few years but when it happens to you it's catastrophic.

[jcollins]

Across the creek from my dock is an Albin 28 named Esperanza at a private pier. The location is at the head of Back Creek in Annapolis. The boat is heavily laden with snow and floating quite low in the water. The swim platform is nearly touching the water. If anyone knows the owner, please give him a call, he appears to be dangerously close to a major problem. The weather forecast is for another 4 to 5 inches of snow on Monday and that could be enough to cause a sinking.

Vessel documentation name query of Albin in Annapolis :

GENE E GODLEY
<address removed>

I just called him. He was out of town but cleaned it off yesterday. Thanks Lou!

[Denis]

I am a very limited user of the internet, but it never ceases to amaze me what can be done on the internet if you know what you are doing. It is also a little scary to know that so much information is available also. It's great you guys were able to help out that boat owner and possibly save his boat. Nice job.

[RobS]

Those photos on photobucket are horrible. However, can't help but to think that in this economy there's gotta be a few owners of the totaled boats that aren't too sad.....

[VA3MRJ]

Here is another thought, do not park the boat close to a roof of a building. I had snow slide off a metal roof and collapse the sundeck on a 40 foot Hershine (Canadian Albin). The marina had parked the stern up against the workshed and I assume the velocity and weight caused the suppports to buckle.We weighed the sundeck at 2,000 lbs when it was lifted off by the crane for repairs.

[Butch]

Well I have been South the entire snow episode, and returned to the Mary B(Albin28) this past weekend. She is in the pond for the winter and I am happy to say that I will be atttending the Albin Owners meeting in Solomons. the Mary B did not sink. Lou, I was reading the Snow loading pundits and did not have a good feeling when I was watching CNN about the 2 Storms of the Century. John, I will be glad to coordinate our rendezvous in Solomons. We need to get Lou to grab some of those Albins in Annapolis and Chief to bring some of those Southern boats to the July festivities. I need to see if I can use Dick's Red Tug as the headquarters for the event. Enjoy the rest of the winter, Spring is less than 30 Days away