Cruisers Forum
 


Join CruisersForum Today

Reply
 
Thread Tools Rate Thread Display Modes
Old 05-01-2010, 15:10   #1
Registered User

Join Date: Sep 2008
Location: Clyde,scotland.
Boat: seadog 30
Posts: 33
Through-Hulls In Polar Regions

iv' thought about this one for some time,google cant answer it,the question is this,boats that sail in the polar regions,do they ever suffer from frozen thru-hulls,if not why not,if they could the consequences could be disastrous,i hope someone can answer this.thanks.Ronnie.
__________________

__________________
bigman1 is offline   Reply With Quote
Old 05-01-2010, 15:59   #2
Registered User
 
cburger's Avatar

Join Date: May 2006
Location: Nyack, NY
Boat: Westsail 32
Posts: 1,547
Images: 1
By through hulls I am assuming you mean seacocks discharging below the water line, (Do to the word disastrous in your post). The answer is that usually the water is acting as an insulative barrier to the through hull if it is discharging far enough below the water line of the boat. If the water is so cold that it is freezing a foot or two below the water line there are other issues more pressing than freezing through hulls. Most skippers that are operating in frigid conditions for any lenght of time know the general areas of their boats that need some extra attention, I.E. insulation, heated spaces etc.
__________________

__________________
cburger is offline   Reply With Quote
Old 05-01-2010, 16:05   #3
Senior Cruiser

Cruisers Forum Supporter

Join Date: Aug 2009
Location: between the devil and the deep blue sea
Boat: a sailing boat
Posts: 17,314
I believe if the water outside is not freezing, the water in the thru-hulls, generally, is not freezing either.

For more extreme cases the intake and discharge may be arranged via wells and such wells can be either warmed artificial circulation may be enforced to avoid ice build-up.

b.
__________________
barnakiel is offline   Reply With Quote
Old 06-01-2010, 00:51   #4
CF Adviser

Cruisers Forum Supporter

Join Date: Aug 2009
Boat: Custom Van De Stadt 47 Samoa
Posts: 3,744
Quote:
Originally Posted by bigman1 View Post
iv' thought about this one for some time,google cant answer it,the question is this,boats that sail in the polar regions,do they ever suffer from frozen thru-hulls,if not why not,if they could the consequences could be disastrous,i hope someone can answer this.thanks.Ronnie.
For summer navigation in the polar regions this is not a problem because the ice is melting, and not freezing.

However, it is a more interesting situation for those few who choose to winter over in the ice. In the NW passage, for instance it can get to -50C and the freezing point of the water is about -2C, so the water surface freezes an average of 1.8m deep (about 6') over the winter. What happens then depends on how much and well the boat is heated and how often a thru hull is used.

For polar designed boats with a lot of power (full time gensets) there is no problem just heating everything and keeping water circulating to stop it freezing solid. But on a more normal cruising boat the situation is more 'interesting'.

In a poorly heated compartment, with a rarely used thru hull, the conventional technique is to pour some sort of antifreeze solution down the pipe into the thru hull and then quickly close the thru hull. If you close the thru hull with the straight salt water in it, the water might freeze and expand and crack the thru hull.

Of the three cruisers we know well who have wintered over, two were able to use their head thru-hulls all winter (I presume because they heated their boat well and pumped the head several times a day) and one has his freeze (he ran very short of heating fuel and let the boat get very cold) and had to go to a bucket. But that frozen pipe caused no damage.

All three boats had a different problem with the thick ice. It froze around their props early in the winter. Then more snow fell and the ice thickened and the sterns of the boats were dragged down (while the bows stayed floating on top of the ice). All three came to such an angle that there was serious danger and all three had to cut the ice around the transoms to let the sterns pop up. Fortunately a chain saw turns out to cut ice pretty easily.
__________________
estarzinger is offline   Reply With Quote
Reply

Thread Tools
Display Modes Rate This Thread
Rate This Thread:

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Thru-Hulls in Cored Hulls ggray Construction, Maintenance & Refit 7 22-12-2009 09:07
Polar for the Sun Odyssey 36i johnbenq Monohull Sailboats 1 06-06-2008 03:53
Same old, same old in the polar regions knottybuoyz Polar Regions 4 07-03-2008 18:44
Search for Bene361 Polar George P Monohull Sailboats 5 12-01-2008 15:37
Lk. Superior - Not Exactly Polar... GordMay Polar Regions 0 05-11-2003 04:50



Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -7. The time now is 18:45.


Google+
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.
Social Knowledge Networks
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.

ShowCase vBulletin Plugins by Drive Thru Online, Inc.