purplerobbie
Active member
I have just been told that i could have my keel bolts X-rayed to check them rather than drawing them out?
Is there any truth in this?
Cheers Rob
Is there any truth in this?
Cheers Rob
Keel Bolt X-Ray
- Thread starter purplerobbie
- Start date
tillergirl
Well-known member
See http://www.stellasail.org.uk/survey/surveyor.htm for some info and an example
jwilson
Well-known member
Not often done nowadays as health and safety means evacuating the boatyard area....
William_H
Well-known member
X Ray (Radiography) of metal parts is a very tricky science. It is best used to look for a fault where you know exactly where the fault may be.
This is because the alignment of the plate and emitter are very critical.
So Xray is almost hopeless at looking for cracks in metal or bolts but can be usefull to detect a large amount of wastage of the bolt.
So if the picture is taken with correct alignement as the link shows it can detect wasting of the bolt shaft. The alignement will typically be from one side of the keel to the other so rays must go through the keel itself as it seeks to show a shadow of the bolt.
I would suggest that for a boat it will be too expensive and not sufficiently diagnostic of bolt condition. So you should pull a bolt for inspection or simply add more bolts to ensure integrity.
If you decide to go for Xray get an operator who is familiar with yacht keel bolt xrays. Not just a general expert.
olewill
This is because the alignment of the plate and emitter are very critical.
So Xray is almost hopeless at looking for cracks in metal or bolts but can be usefull to detect a large amount of wastage of the bolt.
So if the picture is taken with correct alignement as the link shows it can detect wasting of the bolt shaft. The alignement will typically be from one side of the keel to the other so rays must go through the keel itself as it seeks to show a shadow of the bolt.
I would suggest that for a boat it will be too expensive and not sufficiently diagnostic of bolt condition. So you should pull a bolt for inspection or simply add more bolts to ensure integrity.
If you decide to go for Xray get an operator who is familiar with yacht keel bolt xrays. Not just a general expert.
olewill
cliff
Active member
[ QUOTE ]
So Xray is almost hopeless at looking for cracks in metal or bolts but can be usefull to detect a large amount of wastage of the bolt.
[/ QUOTE ]Absolute tripe! Radiography is used (industrially) day in, day out for just such purposes (checking for cracks etc). Any ½ decent RT technician will be capable of producing satisfactory radiographs - even of keel bolts. The only real issues are alignment, sensitivity, film density and geometric unsharpness. The next issue is the person who is reading the film - that takes a lot of skill (and experience) to get it right.
Unless there are some very good reasons why a bolt cannot be pulled I would forget RT on COST reasons - NOT on technical reasons.
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"Artificial intelligence is no match for natural stupidity"
sailroom <span style="color:red">The place to auction your previously loved boatie bits</span>
So Xray is almost hopeless at looking for cracks in metal or bolts but can be usefull to detect a large amount of wastage of the bolt.
[/ QUOTE ]Absolute tripe! Radiography is used (industrially) day in, day out for just such purposes (checking for cracks etc). Any ½ decent RT technician will be capable of producing satisfactory radiographs - even of keel bolts. The only real issues are alignment, sensitivity, film density and geometric unsharpness. The next issue is the person who is reading the film - that takes a lot of skill (and experience) to get it right.
Unless there are some very good reasons why a bolt cannot be pulled I would forget RT on COST reasons - NOT on technical reasons.
--------------------
sailroom <span style="color:red">The place to auction your previously loved boatie bits</span>
tillergirl
Well-known member
Having seen the 'anti-smuggling' x ray devices at our ports, I'm with Cliff. Those devices can 'see' the level of the oil in the diff and teeth on cogs in geraboxes. It will though be a issue of cost and availability of the right stuff.
Niander
New member
There is one more thing as it says on the link ...
it cannot possibly "see" the condition of the threaded part of the bolt in the cast iron keel itself can it....
I'm actually interested in the add more bolts method[just to be sure]
Im thinking of doing this myself.
any ideas on how to do this?....sister wood drill/tap into keel?
it cannot possibly "see" the condition of the threaded part of the bolt in the cast iron keel itself can it....
I'm actually interested in the add more bolts method[just to be sure]
Im thinking of doing this myself.
any ideas on how to do this?....sister wood drill/tap into keel?
