When checking and old sailboat to make sure the balsa core is dry, not
saturated with moisture ....

I know that the surveyer will tap with a hammer... What kind of hammer?
And explain what and how the hammer tapping tells the story of the deck.

Any other deck check methods ?

Also,, if stanchions need re-bedding. First loosen up and remove the nuts
under [ right? ], Then remove the stanchion base. OK OK..

Now what ?? Can I just scrape off the old sealer, clean up and put new
sealer down and then reattach?

I have seen where some sailors recommend putting a backing plate under.
Makes sense to me. What material besides metal can one use? Cutting
stainless steel is kinda hard. Is there something else that will work?

Thomas,

Question 1:
There is a small problem with this method of evaluation.

I use a two sided soft face hammer from Sears. It is still about 10$us.
You could spring for the heavier, but is costs more is heavier to
carry and doesn't tell you any more (I have one of those and I don't
keep it in my bag.

Now is where it gets real tricky. I have though about teaching a class
on this, but I just haven't put it together.

Case 1 - Solid - chrisp thunk, the hammer comes back the with the
energy it when in (like you hit a good 2*4)= Solid layup with minimal
moisture.

Case 2 - Solid thunk (lower natural frequency than above), but lacks
chrispness and the hammer does not quite come back the way it when
in..... Well, the laminate is still solid, but has enough moisture to
increase the mass of the core.

Case 3 - Soft thunk, nothing chrisp here and the hammer feels like it
might stick (comes back with WAY less energy than it when in). Start
devaluing right now, the laminate has delaminated. There is now way to
tell the actual condition of the core, but it doesn't matter either.

Case 4 - Thunk is not solid, but is not soft - if you really listen you
hear the thunk-UNK when you hit and the rebound is just not right (but
not really wrong either) - You have just hit a very rare case of dry
delam. This is either the result of an OED (Original Equipmment Defect)
that occured becuase the crew didn't get the core stuck before the
resin tripped - OR - it can also be the result of impact or overload
damage. Examine the skin in the area very closely. It migth have been
repaired without the damage to the core repaired as well.

Question 2:
I also always carry a laminate moisture meter in the same bag. There
are many on the market and Practical Sailor didn't think much of most of
them. The unit I have had for a number of years now is a Tramex Skipper
and it probably goes for something close to 500$us by now.

Further discussion:
A hammer is a very good survey tool to tell you real fast if there is
damage. It can NOT reliably report moisture content. A high buck
moisture meter can only report the moisture content of the laminate and
can not tell you if the structure is solid. People always marvel that I
carry both a 10$ hammer and a 400+bean meter and that I get them both at
a the same time very often.
= Thought question for you. What is the chance that the high buck
meter can identify a impending problem that can be stopped before it
costs more than the friggin little box cost?

Question 3:

You basicaly have the plan, but remember to get sealer under the
fastener heads and fill the threads so intrusion can't find a way into
the laminate. Real Good Idea - If you are fastening to core structure.
Clear out the core in the fastener locations, then fill with a filled
epoxy (the Gougeon bros books tell all about this - get it) and redrill.
Then - when the bedding goes bad again, water can't get into the core
from the fastener holes.

Question 5:
Backing paltes are there to distribute the fastener load. If you are
going to count on it make the fastened item more secure, do that with
glass weight and stiffen the actually structure. As for backing plates,
Aluminum works as well as stainless. And, it will work even better if
you put a piece of marine ply between the plate and the inner skin to
prevent the plate from point loading the laminate.

Now- I hope you aren't doing the screen equivalent of a deer in the
headlights look.

I tried to give you complete answers. If I lost you and you can phase a
question that might clear things up - try again - I'm here alot. If you
didn't understand enough to actually phrase a direct question, please
say so and I will try again. I am not kinding about teaching this as a
course some day.

Matt Colie A.Sloop "Bonne Ide'e"
Lifelong Waterman, Licensed Mariner and Perpetual Sailor


Thomas Wentworth wrote:
When checking and old sailboat to make sure the balsa core is dry, not
saturated with moisture ....

I know that the surveyer will tap with a hammer... What kind of hammer?
And explain what and how the hammer tapping tells the story of the deck.

Any other deck check methods ?

Also,, if stanchions need re-bedding. First loosen up and remove the nuts
under [ right? ], Then remove the stanchion base. OK OK..

Now what ?? Can I just scrape off the old sealer, clean up and put new
sealer down and then reattach?

I have seen where some sailors recommend putting a backing plate under.
Makes sense to me. What material besides metal can one use? Cutting
stainless steel is kinda hard. Is there something else that will work?

Matt Colie writes:

I use a two sided soft face hammer from Sears.

Have you ever tried dropping a golf ball? Gives you a visually
quantitative response.

"Richard J Kinch" wrote in message
. ..
Matt Colie writes:

I use a two sided soft face hammer from Sears.

Have you ever tried dropping a golf ball? Gives you a visually
quantitative response.

Hardly non-destructive testing .......

Richard,

Strange you should bring that up.
A client had been attempting the same thing. He had lost at least an
half dozen before he saw my hammer. He had been standing on the deck
playing "drop and catch". The sound places were not a problem, but the
really soft places would cause so little rebound that he could not field
the ball and it would often escape. He was also have some accuracy
issues.

The hammer can give very readable response both visual and tactile, and
the hammer can do as well on surfaces that are far from horizontal or
significantly curved.

But - Hey - Whatever floats Your Boat - So to Speak

Matt Colie


Richard J Kinch wrote:
Matt Colie writes:


I use a two sided soft face hammer from Sears.


Have you ever tried dropping a golf ball? Gives you a visually
quantitative response.

Matt Colie writes:

A client had been attempting the same thing. He had lost at least an
half dozen before he saw my hammer. He had been standing on the deck
playing "drop and catch". The sound places were not a problem, but the
really soft places would cause so little rebound that he could not field
the ball and it would often escape. He was also have some accuracy
issues.

If we just had a technology to keep a bouncing ball from going overboard.

Like a picture-hanging eye and some elastic cord from the sewing notions.