Cruisers Forum
 


Join CruisersForum Today

Reply
 
Thread Tools Rate Thread Display Modes
Old 15-02-2015, 17:33   #121
Registered User

Join Date: Oct 2007
Location: Winters cruising; summers Chesapeake Bay
Boat: Catana 471
Posts: 1,239
Re: Saba 50 vs Antares

Quote:
Originally Posted by smj View Post
I wonder which would flood quicker, losing a shaft in a shaft drive or losing both seals in a sailsdrive boat.
Well, let's explore that.

Which sail drive seals are you talking about?

"Both seals" to me means the two seals on the prop shaft, which if both happened to completely fail - however remote that may be - would result only in the sail drive fluid getting contaminated with sea water and losing sail drive oil to the sea. Nothing, however, gets into the vessel. If the boot seal or "bellows" fails, the engine room would be flooded up to the water line. The rest of the boat - assuming a separated engine room - may not even know it happened.

Dave
__________________

__________________
2Hulls is offline   Reply With Quote
Old 15-02-2015, 17:37   #122
smj
Registered User

Join Date: Nov 2007
Boat: Searunner 38 catamaran
Posts: 3,654
Re: Saba 50 vs Antares

Quote:
Originally Posted by 2Hulls View Post
Well, let's explore that.



Which sail drive seals are you talking about?



"Both seals" to me means the two seals on the prop shaft, which if both happened to completely fail - however remote that may be - would result only in the sail drive fluid getting contaminated with sea water and losing sail drive oil to the sea. Nothing, however, gets into the vessel. If the boot seal or "bellows" fails, the engine room would be flooded up to the water line. The rest of the boat - assuming a separated engine room - may not even know it happened.



Dave

I was talking seal and bellows but wouldn't count on the assuming part
__________________

__________________
smj is offline   Reply With Quote
Old 15-02-2015, 17:43   #123
Registered User

Join Date: Sep 2009
Location: Mackay,QLD, Australia
Boat: planning a approx 45ft cat
Posts: 3,651
Images: 3
Re: Saba 50 vs Antares

There have actually been cases of ropes around saildrive props sinking vessels.
__________________
downunder is offline   Reply With Quote
Old 15-02-2015, 18:03   #124
Registered User

Join Date: Oct 2007
Location: Winters cruising; summers Chesapeake Bay
Boat: Catana 471
Posts: 1,239
Re: Saba 50 vs Antares

Quote:
Originally Posted by smj View Post
I was talking seal and bellows but wouldn't count on the assuming part
OK, on most sail drive boats the sail drive and bellows is in an isolated engine room. That's the case on my boat. If the bellows fails, the engine room gets flooded up to the water line + a little more. On my boat that wouldn't even disable the engine, much less swamp the boat.

For a failed shaft, the flooded volume would have to be similarly contained. This may be easily achievable, but how often is it?

Dave
__________________
2Hulls is offline   Reply With Quote
Old 15-02-2015, 18:48   #125
smj
Registered User

Join Date: Nov 2007
Boat: Searunner 38 catamaran
Posts: 3,654
Re: Saba 50 vs Antares

You have more faith than I.
__________________
smj is offline   Reply With Quote
Old 15-02-2015, 18:58   #126
Registered User

Join Date: Oct 2007
Location: Winters cruising; summers Chesapeake Bay
Boat: Catana 471
Posts: 1,239
Re: Saba 50 vs Antares

Quote:
Originally Posted by smj View Post
You have more faith than I.
In what way - hoping shaft failures would be contained? If I was designing a shaft drive boat that's the way I would do it.

Dave
__________________
2Hulls is offline   Reply With Quote
Old 15-02-2015, 19:01   #127
smj
Registered User

Join Date: Nov 2007
Boat: Searunner 38 catamaran
Posts: 3,654
Re: Saba 50 vs Antares

Faith in your engine not taking on water. Maybe in calm water.... But I would doubt it.
__________________
smj is offline   Reply With Quote
Old 15-02-2015, 19:19   #128
Registered User

Join Date: Jan 2014
Location: Sydney, NSW
Posts: 680
Re: Saba 50 vs Antares

Quote:
Originally Posted by downunder View Post
There have actually been cases of ropes around saildrive props sinking vessels.
Witness the case of the Lagoon in Thailand that sunk because the engine compartment was not waterproof and flooded the hull. Then long legal battle ensued.

Anyone with saildrives would do well to make sure their engine compartment is water tight and that the manufacturer guarantees, in writing, that it is.
__________________
BigBeakie is offline   Reply With Quote
Old 15-02-2015, 19:36   #129
Registered User

Join Date: Oct 2007
Location: Winters cruising; summers Chesapeake Bay
Boat: Catana 471
Posts: 1,239
Re: Saba 50 vs Antares

Quote:
Originally Posted by smj View Post
Faith in your engine not taking on water. Maybe in calm water.... But I would doubt it.
Well, come visit and see for yourself. The starter might get wet........

Dave
__________________
2Hulls is offline   Reply With Quote
Old 15-02-2015, 20:16   #130
Registered User

Join Date: Jun 2007
Location: SW Florida
Boat: FP Belize, 43' - Dot Dun
Posts: 3,427
Re: Saba 50 vs Antares

Quote:
Originally Posted by smj View Post
I wonder which would flood quicker, losing a shaft in a shaft drive or losing both seals in a sailsdrive boat.
You need to worry about the extent of flooding the entire hull vs. an engine room with solid bulkheads fore/aft of the engine. I lose both seals on my saildrive and take on maybe 40-50 gallons of water (to the top of the engine oil pan). The Antares loses a shaft and has a completely flooded hull (covering the engine, living space, etc.).
__________________
DotDun is offline   Reply With Quote
Old 15-02-2015, 22:22   #131
Registered User

Join Date: Jan 2014
Location: Sydney, NSW
Posts: 680
Re: Saba 50 vs Antares

Quote:
Originally Posted by DotDun View Post
You need to worry about the extent of flooding the entire hull vs. an engine room with solid bulkheads fore/aft of the engine. I lose both seals on my saildrive and take on maybe 40-50 gallons of water (to the top of the engine oil pan). The Antares loses a shaft and has a completely flooded hull (covering the engine, living space, etc.).
Just curious, what would cause the loss of a shaft? What circumstances would that occur under?

Tearing the boot of a saildrive I get, but what would tear the shaft out of a boat? Assuming it's correctly engineered in the firstplace, naturally.
__________________
BigBeakie is offline   Reply With Quote
Old 16-02-2015, 05:31   #132
smj
Registered User

Join Date: Nov 2007
Boat: Searunner 38 catamaran
Posts: 3,654
Re: Saba 50 vs Antares

Quote:
Originally Posted by DotDun View Post
You need to worry about the extent of flooding the entire hull vs. an engine room with solid bulkheads fore/aft of the engine. I lose both seals on my saildrive and take on maybe 40-50 gallons of water (to the top of the engine oil pan). The Antares loses a shaft and has a completely flooded hull (covering the engine, living space, etc.).

I'm sure it wouldn't be a problem to drive a wooden plug into the empty tube of a shaft drive. Saildrive, maybe a bit more of a problem. We've owned a Saildrive driven catamaran as well as shaft drive, stern drive and outboard. We never had any catastrophic problems with the Saildrive but it would be my last choice. Something about a large chunk of aluminum sitting in the water 24 hours a day exiting through a large hole in the boat doesn't sit well with me. But don't get me wrong, if that's the only way my dream boat came I would accept it.
__________________
smj is offline   Reply With Quote
Old 16-02-2015, 05:53   #133
Registered User

Join Date: Jun 2007
Location: SW Florida
Boat: FP Belize, 43' - Dot Dun
Posts: 3,427
Re: Saba 50 vs Antares

Quote:
Originally Posted by smj View Post
I'm sure it wouldn't be a problem to drive a wooden plug into the empty tube of a shaft drive. Saildrive, maybe a bit more of a problem. We've owned a Saildrive driven catamaran as well as shaft drive, stern drive and outboard. We never had any catastrophic problems with the Saildrive but it would be my last choice. Something about a large chunk of aluminum sitting in the water 24 hours a day exiting through a large hole in the boat doesn't sit well with me. But don't get me wrong, if that's the only way my dream boat came I would accept it.
As with everything, saildrives present trade-offs. Aluminum housing full of shafts, bearings, gears, and oil hanging in the water enables engines to be placed outside the living space in a dedicated engine room. No diesel or oil smell, no heat, and less noise in the living space. And yes, easier and cheaper installation.

Driving a wooden plug into an empty shaft tube might be possible (wearing goggles and snorkel ), but a properly designed engine/saildrive space flooding due to a failure of multiple seals/boots is simply not a catastrophe, i.e., not requiring immediate action to save the boat from sinking.

Yes, slightly more maintenance than shafts, saildrives require proper care. But, 30+ years have proven they are very reliable and trustworthy.
__________________
DotDun is offline   Reply With Quote
Old 16-02-2015, 06:08   #134
smj
Registered User

Join Date: Nov 2007
Boat: Searunner 38 catamaran
Posts: 3,654
Re: Saba 50 vs Antares

Quote:
Originally Posted by DotDun View Post
As with everything, saildrives present trade-offs. Aluminum housing full of shafts, bearings, gears, and oil hanging in the water enables engines to be placed outside the living space in a dedicated engine room. No diesel or oil smell, no heat, and less noise in the living space. And yes, easier and cheaper installation.

Driving a wooden plug into an empty shaft tube might be possible (wearing goggles and snorkel ), but a properly designed engine/saildrive space flooding due to a failure of multiple seals/boots is simply not a catastrophe, i.e., not requiring immediate action to save the boat from sinking.

Yes, slightly more maintenance than shafts, saildrives require proper care. But, 30+ years have proven they are very reliable and trustworthy.
You hit it on the head when you said easier and cheaper installation. In my opinion that's why the manufacturers use them.
I'm not sure about the reliable and trustworthy statement. I've seen my fair share of saildrives that have corroded completely through and having to replace cone clutches every few hundred hours on some of them? They have found their place in the market but I personally don't care for them.
__________________
smj is offline   Reply With Quote
Old 16-02-2015, 06:34   #135
Registered User

Join Date: Jun 2007
Location: SW Florida
Boat: FP Belize, 43' - Dot Dun
Posts: 3,427
Re: Saba 50 vs Antares

Quote:
Originally Posted by smj View Post
You hit it on the head when you said easier and cheaper installation. In my opinion that's why the manufacturers use them.
I'm not sure about the reliable and trustworthy statement. I've seen my fair share of saildrives that have corroded completely through and having to replace cone clutches every few hundred hours on some of them? They have found their place in the market but I personally don't care for them.
That's why they still make transmissions and shafts.

FWIW, improperly maintained transmissions/shafts are not trouble free.
__________________

__________________
DotDun is offline   Reply With Quote
Reply

Tags
Antares, Saba

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
Saba - any good anchorages or mooring balls? kenton.sparks Atlantic & the Caribbean 8 02-01-2012 06:49
Saba Island in North Swells - Lunacy or Contentment Dreaming Yachtsman Atlantic & the Caribbean 9 27-02-2011 12:38
SCUBA at Saba karenmccraw Atlantic & the Caribbean 4 13-04-2010 20:49
Antigua - Nevis - Saba - St. Martin - Anchor in North Swells west coaster Atlantic & the Caribbean 12 01-03-2009 21:22
Dive Company Recmmendations for St Martin/Saba/Anquila/St Barts??? Lightfin Fishing, Recreation & Fun 1 13-12-2005 09:40



Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -7. The time now is 14:03.


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.