Snow!!!

[Quickstep192]

The forcast here is once again calling for large amounts of snow. I've always shoveled the snow off the boat in these circumstances, but I'm gettign old and shovelling the snow off of the boat is getting old too. That led me to wonder, just how much snow can a boat have on it before there's risk of sinking? In my case, the cockpit scuppers are about a foot above the water line. Seems like the weight of the snow ends up pretty well distributed, so I'd guess that it would take a lot to lower the boat any significant amount, but I wondered if anyone here had any practical (hopefully not tragic) experience.....

[chef2sail]

Cover you boat with canvas...or at least the cockpit area. Its relatively easy to do even without buying or making as we did a custom canvas cover in two pieces. Buy the cheap blue pvc covers with gromets and stretch them over your boom then down to the toe rail and tie with bungees or line. This will [protect a lot of the area and prevent the cockpit from filling up with snow.

Dave

[BubbleheadMd]

You can also weight the tarp down with milk jugs full of water if you have no good attachment points. Tie them to the tarp grommets with line.

As far as what can go wrong? What I've heard of happening this winter, is that boats that get pushed down, due to increased water pressure, are having water backup through inboard engine water intakes, blowing the hoses off of seacocks and flooding down.

If your intakes are dry and shut, and your seacocks are shut, hoses double-clamped, you should be ok.

Also, if you make a tent over the boom, and the cockpit remains empty, the snow will pile onto the forward deck, maybe it'll raise the stern and keep most of your seacocks from being pushed deeper underwater.

[SVPrairieRose]

In Nanaimo a few years back during a particularly bad winter the crew at a marina came to the realization that salt melts snow, that salt water has salt in it and that shoveling tin shed roofs was a PITA. So, armed with gas pumps and fire hoses they went to work. They got a fast lesson in the water holding characteristics of snow. Many, many sheds collapsed with very expensive boats inside.

[AdamLein]

That's a scary story, though it reminds me that a bucket of seawater is a good way to temporarily de-ice the docks.

As to the OP's question, packed snow is about 30% as dense as water. So if I want to displace an inch more water I need roughly three inches of packed snow on the deck (my hull is not a cylinder but whatever). Fortunately the snow that falls isn't all packed, so in practice it's probably quite a bit more snow required to raise the waterline by an inch.

If I set up a boom tent and get negligible snow buildup around it, I might get 40% (10' boom on a 27' deck, bow is not very wide) less snow buildup overall so I'd need seven or eight inches of snow to get the same average rise in waterline, and as Bubblehead points out, it would be lifting many of the through-hulls out of the water (though hard to tell how much because you're fighting against the fore-and-aft righting moment of the keel).

[SVAuspicious]

I've had up to 8" snow on deck. Generally when it is really heavy I just keep the scuppers clear and the bit of deck I need to get on and off the boat.

[AdamLein]

I've never had quite that much and while I thought she was sitting a bit low I wasn't sure if it was just my imagination or not. Did you happen to notice where your waterline was?

[jaschrumpf]

A few weeks ago we had an ~12" snowfall here in the Baltimore area. I didn't cover up my boat (1975 Newport 28) at all, and when I went to check on her a couple of days after the storm she was riding high, waterline not appreciably down and only the cockpit had snow in it. There was also a bit of snow inside the cabin where the wind pushed in through the gap between the washboards and the roof.

I'd say I'm therefore not worried about the storm we're about to get (~24"), but that would be tempting fate, so I won't. I'll check on her ASAP after the storm, and she'll be in my thoughts all day long.

[BubbleheadMd]

Yeah, I'm not taking anything for granted. I'll be checking on mine all weekend.

[SVAuspicious]

Just finished clearing snow for the fourth time. Back to sleep with a two hour timer to get up and do it again. *sigh* I'd rather be standing watches somewhere.