What temp is really "freezing" on the water?

[chasmains]

Let’s refresh folks on the freezing temperatures of fresh water and seawater.
1. Freezing point of fresh water: 32.0 deg. Fahrenheit, 0.0 Deg. Celsius.
2. Freezing point of world average seawater: 28.4 deg. Fahrenheit, -2.0 deg. Celsius.

Average seawater contains approximately 35g salt per liter of water. But an important aspect is that river water running into seawater lowers the total salt per liter, which raises the freezing point toward 32 deg F. Mid Chesapeake Bay is likely close to average seawater at high tide. So prepare for freezing seawater and you won’t freeze in or near freshwater.

[Pillroller]

I would be more concerned about the rain rather than the cold on the sails. They may grow things like Verdigris or moulds, if cold and damp.
Take them down and take them home if possible, but in the cabin would be netter than nothing.
Take your sheets home and give them a bath in fresh (Warm?) water to get rid of salt. The crystals can be quite hard and in drier weather can cause wear in the running
rigging when you use them in anger next year.
I'd love your temps here inNorfolf U.K. Robin.

[Cadence]

Originally Posted by guyrj33

If your boat has shore power available there are some safe low power heaters 80-100W that can be placed in the engine compartment and left running.

That or a waterline tape with a thermostat since an incandescent bulb is a thing of the past. You will be fine tonight. One of those tapes are cheap and can be had in different lengths and wattages at any hardware store. the thermostats are fixed at about 32 degrees.

[garyfdl]

One night at 31 F isn't going to hurt anything, especially as you should be in brackish water. If you are faced with a prolonged period (3+ days) of below freezing temps, you should probably consider winterizing the engine and water systems.

As to sails? Were it me, I'd get the sales off, and store them at home. Wet sails, left up and not properly dried can mildew. The boat is likely to be damp as well and the sails might even mildew if kept onboard. Take 'em down and take them home.

[boat driver]

east beach= For the east coast the discussion -winterizing- is considered essential north of norfolk- and south is more of simply exterior prepping for freezing.
The water temp does play a hand in keeping a vessel warmer, but a couple days below 32F will freeze all the interior fresh water plumbing. Therefore,
if you are planning to use the boat over the winter months- minimize fresh water in the plumbing and head, same in the engine, and close the hatches. Hardwired to the vessel system and mounted heat can be helpful, but be sure your insurance and marina permit the heater.
Otherwise, run pink antifreeze through the fresh water system and just do day sails.
If you are unsure, ask the marina service department their opinion.

[Onthehard]

I have a small electric heater plugged into one of these thermostatically controlled outlets with door open to engine compartment. Turns heater on at 35F in the cabin and off at 45F.

https://www.amazon.com/Farm-Innovato...0006U2HD2?th=1

[boat driver]

Originally Posted by Onthehard

I have a small electric heater plugged into one of these thermostatically controlled outlets with door open to engine compartment. Turns heater on at 35F in the cabin and off at 45F.

https://www.amazon.com/Farm-Innovato...0006U2HD2?th=1

ON the hard- check your insurance policy and the yard policy about that switch and heater. You might discover it voids your insurance.

[Onthehard]

Originally Posted by boat driver

ON the hard- check your insurance policy and the yard policy about that switch and heater. You might discover it voids your insurance.

Thanks for the heads up. I will check.

[MJH]

Originally Posted by mhinnc

Q. Is there a general rule of having a little lee-way, temperature wise, in winterizing a boat?

This summer we acquired a C&C 30. It is docked at East Beach/Norfolk.
The boat has a raw water Atomic 4 engine. It's our first boat with an inboard.

The forecast is for the air temp to drop to 31 deg F tonight. Specifically, the current forecast is: "Clear to partly cloudy. Low 31F. Winds WNW at 5 to 10 mph." The forecast is for the air temp to be a high of 47 deg F today.

This is the first sub 32 deg for this season. Original plans were to go up today anyway. (I'm 5 hours inland), but some things popped up that makes it a little difficult to get there today, but not impossible to get there by late this evening.

Does the inside boat temp (sunshine), help hold a little heat through the evening; does the water temp under the boat help provide any relevant warming? Should I drop everything and make a bee line for the boat to winterize it?

Thanks for any advice/insight.

Welcome to the world of boat ownership.

Another thought is, How much can you afford to replace the engine or water tanks that freeze?

I live in the Pacific NW and the weather rarely gets below freezing for long and I doubt many winterize their boats here. However, on an early visit to the local museum there was a photo of someone ice skating on the local bay back in 1952. That's all I need to winterize my boat every winter because I can't afford to replace the diesel or the two 100 gallon s.s. fresh water tanks under the salon flooring which would have to be torn up.

I don't want to wait for a weather warning to get my butt out to the boat to do what should have been done as a preventative measure weeks or months ealier. My boat is moored to a buoy 24/7/365 and an impending freeze means that what could have been done in preferred weather is now going to be done in something much worst.

~ ~ _/) ~ ~ MJH

[waterman46]

Originally Posted by chasmains

Let’s refresh folks on the freezing temperatures of fresh water and seawater.
1. Freezing point of fresh water: 32.0 deg. Fahrenheit, 0.0 Deg. Celsius.
2. Freezing point of world average seawater: 28.4 deg. Fahrenheit, -2.0 deg. Celsius.

Average seawater contains approximately 35g salt per liter of water. But an important aspect is that river water running into seawater lowers the total salt per liter, which raises the freezing point toward 32 deg F. Mid Chesapeake Bay is likely close to average seawater at high tide. So prepare for freezing seawater and you won’t freeze in or near freshwater.

Backwards? Prepare for freshwater and you don't have to worry about salt water, right?

[Free2Sail]

Originally Posted by mhinnc

Q. Is there a general rule of having a little lee-way, temperature wise, in winterizing a boat?

Does the inside boat temp (sunshine), help hold a little heat through the evening; does the water temp under the boat help provide any relevant warming? Should I drop everything and make a bee line for the boat to winterize it?

Thanks for any advice/insight.

I had a similar worry a couple of nights ago. The temps were forecast to drop to mid-20s F for a few days. The boat is in seawater. When I went down to check and winterize the engine, the raw water intake and the engine block were at about 48F while the ambient air temp was in the low 30s and dropping. So, it would've been fine for now, but having winterized it I don't have to worry.

[mhinnc]

The C&C 30 came with a porta-potty, the PO having removed the head, tank and lines. The onboard fresh water ran out last time there, so now there's residual water only in the lines and pump. The previous owner equipped the icebox with a pump pulling water from it and pushing it to the sink drain. This will need antifreeze as well as the bilge, running the bilge pump until antifreeze exits. Pink, I suppose. Seacocks will be closed, except for scuppers.



Because the marina supplies power, I looked into the idea of a low power AC heater in lieu of winterizing, but was advised by an experienced local old salt that in the conditions when it's most needed, there's the possibility of power failures. So, I'm inclined to go the route of draining the block and provide adequate antifreeze through the engine & exhaust, which doesn't have a water muffler yet.


The sails will be returning with me next time up.


I believe I'm getting some understanding in this area. Thanks much for the ideas.

[AKA-None]

Originally Posted by Rohan

I agree as far as the engine goes, since the boat is in saltwater.



However, I don't know what systems the C&C 30 has, although I assume it's pretty basic. But if the OP has a water tank, and/or a head that uses fresh water, then those systems need to be winterized.

Don’t forget the holding tank

[Peeew]

I’m based at the same area but I’m not usually there in cold weather. I did ask the rental fleet guys what they do to winterize their sailboats for the winter. They said they turn off the fresh water pump and open all the taps. If you have a deck fresh water shower I would remove that since it is so exposed. A safe space heater is a good idea when it gets real cold.

[Helmling]

See this site for weather buoy information: https://buoybay.noaa.gov