Thanks for your help.
Marshall
"gregg" wrote in message
...
MarshallE wrote:

Hi,

I own a old Wheeler 83 footer

83 feet? Interesting. how old is the boat?

that has had marine grade plywood fastened
to
the the planking and then fiberglassed to around an 1/8" thick. The
work
was done in the mid 1980's and appears to be in good shape below the
water
line. On the inside a few of the frames/ribs are rotten but the
planking
appears to be in excellent condition.

Question- What is the best way to fasten new frames/ribs from the
inside
without penetrating the fiberglass skin? I am guessing that most would
agree to not create places for water to penetrate.....but I am new to
wood
boat repairs. My goal is to restore my old boat to like new condition.

there's no good way to fasten the ribs to the planks from the inside.
Since
you describe the boat as having planks and ribs, it sounds like it's a
"traditionally" built boat. If so the engineering design of the structure
and fasteneings require tha tthe screws be driven in from the outside.

First off the ribs are usually oak or some other hardwood which provides
great holding power for the screw threads - the screw head clamps the
plank
to the rib - there's just a hole through the plank with very little
threading in the plank if any. When you drive screws from the inside out
the threads engage weaker wood from the standpoint of thread holding
power.

Secondly, when the boat works in a seaway, and the boat twists, the
planks
tend to slide for and aft. The beveled underside of the screw heads tends
to force the plank more tightly to the rib when the planks work. You lose
this if you drive the screws from the inside going out.

I doubt you'll get sufficient holding power if you drive the screws from
the
inside out.

Lastly, how do you intend to remove the old screws that are already there,
if you don't pull them from the outside? If you imagined you would just
saw
them flush then you are adding more holes to the plank when you drive in
new screws in a different position.

I would think you could replace the fiberglass over the planks, in the
area
of the ribs to be replaced, if you remove some to get at the screws.

Also if the ribs are rotted, as you say, then I'd inspect the surfaces
where
the ribs are attached to the "floors" - often trapezoidal wooden stretures
that are bolted to the keel at right angles and allow you to connect the
ribs, structurally, to the keel.

Best of luck.


--
Saville

Replicas of 15th-19th century nautical navigational instruments:

http://home.comcast.net/~saville/backstaffhome.html

Restoration of my 82 year old Herreshoff S-Boat sailboat:

http://home.comcast.net/~saville/SBOATrestore.htm

Steambending FAQ with photos:

http://home.comcast.net/~saville/Steambend.htm