[Public-List] Bulkheads

[Hernán Scarnichia via Public-List]

Michael,
I thought about adding bushings. There is an article on wooden boat #206
from 2009 that describes using G10 tubes and plates to reinforce bulkheads
this way. https://goo.gl/photos/vCozrEUgKh3GdGNH8

On my boat the knees for the forward lower shrouds were too rotten and the
tabbing was de-laminating from the hull so I rebuilt them using 3/4" G10
and made them longer (below the shelf) and better tabbed to the hull. No
bushings needed here as G10 is hard enough.
I will probably replace the plywood on the aft lower knees with G10 too.
For the upper shrouds the bulkhead is not rotten but the bolt heads have
pulled a little bit because of the small washers used. I'm planning on
using a 6"x12"x1/2" G10 backing plate on each side of the bulkhead and
adding some extra bolts to better distribute the load on the wood and
through bolt it to the hull tabbing too. Increasing the bolt size to 1/2
should take care of the slightly deformed holes on the bulkhead.

What size of chain plate will you use? What do most Albergers use when
replacing chain plates?

>From my calculations my current chain plates (3/16x1-1/4) will start
deforming at 4200 lbs. I've read it is recommended to have chain plates 30%
- 50% stronger than the wire so that would be 3/8 x 1-1/2 with 4 1/2" bolts
each.


On Tue, Feb 2, 2016 at 5:44 PM, Michael Connolly via Public-List <
public-list at lists.alberg30.org> wrote:

> Thanks to all who responded to my request.  There is one question still
> unanswered. Has anyone used bushings around the chain plate bolts to
> increase the bearing surface area of the bolts as they pass through the
> plywood bulkhead? Thoughts about making an even larger hole in the plywood.
> Michael #133
> .
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