Shortcomings of Orienteering (land) compass - SailNet Community

   Search Sailnet:

 forums  store  


Quick Menu
Forums           
Articles          
Galleries        
Boat Reviews  
Classifieds     
Search SailNet 
Boat Search (new)

Shop the
SailNet Store
Anchor Locker
Boatbuilding & Repair
Charts
Clothing
Electrical
Electronics
Engine
Hatches and Portlights
Interior And Galley
Maintenance
Marine Electronics
Navigation
Other Items
Plumbing and Pumps
Rigging
Safety
Sailing Hardware
Trailer & Watersports
Clearance Items

Advertise Here






Go Back   SailNet Community > On Board > Gear & Maintenance
 Not a Member? 
  #1  
Old 10-15-2010
Junior Member
 
Join Date: Jul 2008
Posts: 7
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 0
Hewie is on a distinguished road
Shortcomings of Orienteering (land) compass

How is a marine hand bearing compass (ie Iris 50) superior to a bearing compasses for land navigation (ie Silva Type 20)? I have a couple of the latter, but am wondering how the marine compasses may be superior.

Thanks,
Dave
Reply With Quote Share with Facebook
  #2  
Old 10-15-2010
sailingdog's Avatar
Telstar 28
 
Join Date: Mar 2006
Location: New England
Posts: 43,291
Thanks: 0
Thanked 9 Times in 9 Posts
Rep Power: 13
sailingdog is just really nice sailingdog is just really nice sailingdog is just really nice sailingdog is just really nice sailingdog is just really nice
Well, first the marine ones usually are designed to float... second, they're designed to be read at eye level while sighting on the target. Third, they're probably better stabilized/damped than the terrestrial ones.
__________________
Sailingdog

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.

Telstar 28
New England

You know what the first rule of sailing is? ...Love. You can learn all the math in the 'verse, but you take
a boat to the sea you don't love, she'll shake you off just as sure as the turning of the worlds. Love keeps
her going when she oughta fall down, tells you she's hurting 'fore she keens. Makes her a home.

—Cpt. Mal Reynolds, Serenity (edited)

If you're new to the Sailnet Forums... please read this
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
.

Still—DON'T READ THAT POST AGAIN.
Reply With Quote Share with Facebook
  #3  
Old 10-15-2010
RichH's Avatar
Senior Member
 
Join Date: Jul 2000
Location: Pennsylvania
Posts: 2,799
Thanks: 9
Thanked 69 Times in 62 Posts
Rep Power: 15
RichH will become famous soon enough
The Iris 50 (and the military types of hand bearing compasses) have a prism/lens which simultaneously splits the view: one view is the compass scale (degrees), the other view is the object to which you are looking at.

The Silva type of compasses do not have such a prism (or lens / 'gun-sight' as with the military type compass) with which to 'split' the view, so your eyeball has to alternately 'focus' between the 2 views.

You typically use the Silva type by holding such at some distance from your eyeball (to view the 'pointer'), the prism types are held next-to-the-eyeball and therefore are vastly more 'sensitive' and more accurate.
Reply With Quote Share with Facebook
  #4  
Old 10-15-2010
sailingdog's Avatar
Telstar 28
 
Join Date: Mar 2006
Location: New England
Posts: 43,291
Thanks: 0
Thanked 9 Times in 9 Posts
Rep Power: 13
sailingdog is just really nice sailingdog is just really nice sailingdog is just really nice sailingdog is just really nice sailingdog is just really nice
While the IRIS 50 does have a prism, it doesn't split the view. It merely allows you to read the compass without having to look down at the compass card.



If you look at the compass, you can clearly see that you can not view through the prism...the outboard end is covered by rubber.

Quote:
Originally Posted by RichH View Post
The Iris 50 (and the military types of hand bearing compasses) have a prism/lens which simultaneously splits the view: one view is the compass scale (degrees), the other view is the object to which you are looking at.

The Silva type of compasses do not have such a prism (or lens / 'gun-sight' as with the military type compass) with which to 'split' the view, so your eyeball has to alternately 'focus' between the 2 views.

You typically use the Silva type by holding such at some distance from your eyeball (to view the 'pointer'), the prism types are held next-to-the-eyeball and therefore are vastly more 'sensitive' and more accurate.
__________________
Sailingdog

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.

Telstar 28
New England

You know what the first rule of sailing is? ...Love. You can learn all the math in the 'verse, but you take
a boat to the sea you don't love, she'll shake you off just as sure as the turning of the worlds. Love keeps
her going when she oughta fall down, tells you she's hurting 'fore she keens. Makes her a home.

—Cpt. Mal Reynolds, Serenity (edited)

If you're new to the Sailnet Forums... please read this
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
.

Still—DON'T READ THAT POST AGAIN.
Reply With Quote Share with Facebook
  #5  
Old 10-15-2010
jackdale's Avatar
Senior Member
 
Join Date: Dec 2008
Location: Calgary, AB, Canada
Posts: 8,831
Thanks: 26
Thanked 36 Times in 33 Posts
Rep Power: 6
jackdale will become famous soon enough
SD - correct on all counts, as usual
__________________
__________________
ISPA Yachtmaster Offshore Instructor Evaluator
Sail Canada Advanced Cruising Instructor
IYT Yachtmaster Coastal Instructor
ASA 201, 203, 204, 205, 206, 214
As I sail, I praise God, and care not. (Luke Foxe)
Reply With Quote Share with Facebook
  #6  
Old 10-15-2010
Junior Member
 
Join Date: Jul 2008
Posts: 7
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 0
Hewie is on a distinguished road
Looks like another item to add to my wish list. Now to decide between the Iris, Vion, and W&P.
Dave
Reply With Quote Share with Facebook
  #7  
Old 10-15-2010
blt2ski's Avatar
Senior Member
 
Join Date: May 2005
Posts: 6,678
Thanks: 0
Thanked 20 Times in 19 Posts
Rep Power: 10
blt2ski will become famous soon enough
In the end tho, will the Silva work? the simple answer is probably yes it will. But it may not be as accurate due to less dampening vs the Iris model(s). or other equal. BUT, I personally feel, if that is all you have, ie a Silva. use it!

marty
__________________
She drives me boat,
I drives me dinghy!
Reply With Quote Share with Facebook
  #8  
Old 10-15-2010
sailingdog's Avatar
Telstar 28
 
Join Date: Mar 2006
Location: New England
Posts: 43,291
Thanks: 0
Thanked 9 Times in 9 Posts
Rep Power: 13
sailingdog is just really nice sailingdog is just really nice sailingdog is just really nice sailingdog is just really nice sailingdog is just really nice
Quote:
Originally Posted by Hewie View Post
Looks like another item to add to my wish list. Now to decide between the Iris, Vion, and W&P.
Dave
They're basically the same in terms of function. The Iris 50 is the least expensive at about $75 or so. Get it in the Yellow, not the Blue, since if you drop it into the water, the yellow is a lot easier to spot.
__________________
Sailingdog

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.

Telstar 28
New England

You know what the first rule of sailing is? ...Love. You can learn all the math in the 'verse, but you take
a boat to the sea you don't love, she'll shake you off just as sure as the turning of the worlds. Love keeps
her going when she oughta fall down, tells you she's hurting 'fore she keens. Makes her a home.

—Cpt. Mal Reynolds, Serenity (edited)

If you're new to the Sailnet Forums... please read this
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
.

Still—DON'T READ THAT POST AGAIN.
Reply With Quote Share with Facebook
  #9  
Old 10-15-2010
jackdale's Avatar
Senior Member
 
Join Date: Dec 2008
Location: Calgary, AB, Canada
Posts: 8,831
Thanks: 26
Thanked 36 Times in 33 Posts
Rep Power: 6
jackdale will become famous soon enough
Quote:
Originally Posted by Hewie View Post
Looks like another item to add to my wish list. Now to decide between the Iris, Vion, and W&P.
Dave
I currently use a Plastimo Iris 50 and a Morin, but it is not usable at night any more; it is more stable that the Plastimo. The Morin gets more day time use.
__________________
__________________
ISPA Yachtmaster Offshore Instructor Evaluator
Sail Canada Advanced Cruising Instructor
IYT Yachtmaster Coastal Instructor
ASA 201, 203, 204, 205, 206, 214
As I sail, I praise God, and care not. (Luke Foxe)
Reply With Quote Share with Facebook
  #10  
Old 10-15-2010
jackdale's Avatar
Senior Member
 
Join Date: Dec 2008
Location: Calgary, AB, Canada
Posts: 8,831
Thanks: 26
Thanked 36 Times in 33 Posts
Rep Power: 6
jackdale will become famous soon enough
Quote:
Originally Posted by sailingdog View Post
T Get it in the Yellow, not the Blue, since if you drop it into the water, the yellow is a lot easier to spot.
Damn - I bought the blue one.

I always use the neck strap.
__________________
__________________
ISPA Yachtmaster Offshore Instructor Evaluator
Sail Canada Advanced Cruising Instructor
IYT Yachtmaster Coastal Instructor
ASA 201, 203, 204, 205, 206, 214
As I sail, I praise God, and care not. (Luke Foxe)
Reply With Quote Share with Facebook
Reply


Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools

 
Posting Rules
You may post new threads
You may post replies
You may post attachments
You may edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On


Similar Threads
Thread Thread Starter Forum Replies Last Post
No Mans Land eherlihy Destinations 2 03-13-2013 09:34 AM
Land sickness Classic30 General Discussion (sailing related) 13 09-29-2010 09:10 PM
Transporting Over Land ... wind_magic Boat Review and Purchase Forum 20 12-25-2008 04:17 AM
Hello from Okie land Soonerschooner Introduce Yourself 5 08-05-2008 09:24 AM
From a dry land sailor zakynthos Learning to Sail 22 09-07-2007 12:34 PM


All times are GMT -4. The time now is 01:26 PM.

Add to My Yahoo!         
Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2014, vBulletin Solutions, Inc.
SEO by vBSEO 3.6.1
(c) Marine.com LLC 2000-2012

The SailNet.com store is owned and operated by a company independent of the SailNet.com forum. You are now leaving the SailNet forum. Click OK to continue or Cancel to return to the SailNet forum.