Construction Of Superstructure

[dincerd]

HI EVERYONE,

LET ME ASK A QUESTION.
SHE IS A 44 METERS WOODEN LAMINATED BOAT AND THE PROBLEM IS HOW TO JOIN HALF-BEAM TO SUPERSTRUCTURE-BEAM. WITH AN ADDITIONAL VERTICAL WOOD SIZE 120x80, OR JUST WITH 3 LAYERS OF PLYWOOD? WHAT TYPE OF SUPERSTRUCTURE DO YOU PREFER / APPLY? YOU CAN SEE ON ATTACHED PICTURE.

LOOKING FORWARD TO HEARING FROM YOUR THOUGHTS.

HAVE A NICE WEEKEND!

DINCER

[rwatson]

Did I get this right - the plan is showing two alternative methods suggested from the original designer - is that correct?
I am a bit puzzled by the part of the plans that show the vertical beams just sitting on top of the strangely shaped girder. I would expect them to run down beside, for the whole depth of the girder and securely fastened against it for maximum strength. It looks more like they are gussetted with plywood on the plans, but wrongly named as a girder.
Also, assuming both both methods use the same size and thickness of plywood, my thoughts are -
I think that you would probably need to have some vertical supports to lay and fasten the first sheets of plywood to at the start, and to make sure they lie fair and true you would need some sort of framework. This would be especially true if you have curved sides ( following the hull lines). So it wouldnt save all that much work to leave the vertical supports out.
On a boat of this size, and without seeing the rest of the plans, I am wondering if leaving the vertical supports in might be a much better structural method, to provide more lateral support to the superstructure as the boat flexes and bends during use. Comparing 40mm of fairly soft plywood instead of 120mm of vertical beam - a lot more rigid.
I would be inclined to dress and paint the vertical beams before the plywood is applied, as it would be easier to take sharp edges off, and apply a nice shape with powertools before the plywood is in place.

[dincerd]

Yes, this plan consists of two alternative building method of superstructure ( or called doghouse). Here it is built wooden boats up to 50meters and all traditional building methods have been applied. However, increasing the hull size, some structural strength problems appeared, for example in 2-3 years,beams are sliding and broke teak deck or wooden construction. in my opinion, that is the reason of applying non-strength construction methods. I m trying to find a solution of "more-strength" for joining the the hull, from portside to starboard.
In addition, there is mast construction ( nearly 41 meters of main mast) that forced to beams while heeling.
I have worked in steel yacht building as well, and in steel construction, we maek a CLOSED frame in all superstructure, beam + vertical beam + half beam + frame, as neraly shown in alternative "A". I think that may be applied in wooden construction as well??

[rwatson]

Without seeing the full plans, I have attached a sketch of additional details that would seem more robust than the plans you attached.
I still cant figure out what that weird shaped beam in example A is supposed to be.

[PAR]

I have no issue with the way the deck beams are arranged on these two different sketches.

The "girder" is a deck opening carlin.

The side deck half beam is in a tight cantilever, which is typical.

Joining the carlin is a reasonably simple process, if you've use station molds. If the side deck beams are just hanging in space, then they could prove difficult to bend a carlin into.

Pick up you heights for the inboard end of the deck beams and fix them in this location with a brace. Then bend in your cabin carlins.

Many builders will build the house on the shop floor, then place it on the boat.

Dincerd, metal boats have different structural strategies, then wooden. Most metal boats are built with a longitudinal framing system, which typically have continuous ring frames, athwartship. There isn't enough information to know for sure about the boat you are working on, but it appears to be conventional framed, inside of strip planking.

If you really want to make it stronger, then decrease frame spacing a tad, increase planking thickness or consider tie rods in key locations.

Without knowing more about the yacht's scantlings, anything more is pure gues work.