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Structure
StructureDeck Supporting Structure
This section covers the stringers, bulkheads, king plank, hardware supports, compression strut tower and block supports for the sheet lines. Meaning all before the decking.
Preparations
Using the beam marking points from the Hull page, five struts were used to shape the hull. The hull was then taped to meet the beam measurements presented in the plans. Well, within a 1/16" anyway.
Station 6
There are some out there that are permanently mounting eye bolts into a puddle of resin on the forward keel tape area. This builder chooses not to and so formed a bulkhead at station 6. A large eye bolts was installed 1-3/4" down from the flange. This was installed and heavily glued. This bulkhead will then be part of the integrity of the bow during a collision. A Pekabe block was attached.
The Ribs
The ribs are 1/4 x 1-1/2 basswood and sanded to form around the flange and to receive the 1/4 x 1 basswood king plank down the centerline. A taunt string was used to identify the centerline to the ribs for the king plank notch. More importantly, it was used to mark the height of the rib. The notches for the flange were cut as deep as needed for the string to touch the crest of the rib. Then the deck side of the rib was rounded so the covering sheet will flow to the shear line. Masters were made during the process so this will not need to be repeated.
It is also suggested that you document each rib as many do not fit the same. This is a big and thick hull and things can be different; hull to hull or location to location. It was found that once fitted they must go back in the same orientation. That is what Boeing would do.
Note: 1-1/2" wide basswood was not found nor was Lone Star Balsa (may not be a source now) queried to make it. It was cut here from a larger sheet. So don't bust your bottom looking for it. Some 1-1/4" was used on the smaller ribs because it was in stock.
If you have not been through the game like the monkey and the football, here is a hint. Take the ribs one at a time and add a dab of filling CA glue on a contact point and insert the rib in its proper place. Use an accelerator and wait 15 minutes then add on the thickened resin glue. Keep the hull taped to shape and let stand at least 24 hours. Be safe or you will have a mess.
There is no need for a stringer at station 87 for hull stability. It is there to receive the king plank and still provide room for the backstay bolt threading.
Note Esthetics: It is suggested that you do not notch ribs 45, 57, 70 and 76 for the king plank. It would be a touch of class to end the king plank on the other side of the two hatches. To support it, glue a piece of 1/4" stock for the king plank to rest on while gluing. It was not thought of here till after the forward king was glued in. A piece of 1/8" basswood sheet was used to correct the omission.
Rib 76
This rib is left out till the rudder is installed. It was one of those things learned on the first boat, which needs to have the rudder removed in order to remove the tiller and linkage.
Rib 76 is positioned after whatever design is used in the rudder compartment for the servo and linkage. This design and the cutting of the rudder sleeve and shaft are married so the tiller arm can be removed upward off the shaft. This rib is for deck and aft king plank support and can be less than 1-1/2" deep.
Compression Strut Tower
The building and fitting of the strut is coordinated with the electronics section and in the end gluing in the primary ballast then the strut. The sheet lines are considered so the rub rod location can be determined and installed. All of these things move along easier while the strut is removable. (If you use the System Board design mentioned in the Electronics section, think this part out here. No big deal.)
A supporting mast base of wood laminate was fitted between stations 37 and 41 and flush with the king plank slot. Two struts were glued and pinned to the support and trimmed at the base so the support is flush in the king plank slot. A cross brace at the base was glued in for stability.
The base of the strut was marked on the ballast and the radio rack fitted for installing the guide screws in the strut. The rack was aligned for marking the rear adjustment and securing screw.
If you would like to moisture protect the strut tower, a good time to do it is while the ballast is curing in the hull. The Delrin sheet rub rod was installed after the painting of the resin. The final is to glue the strut in place keeping the king plank slot clear.
Forward King Plank
The 1/4 x 1" plank is fitted from station 9 to 45. Another stick was placed under the jib rack location for added screw support. Fuss with this and check the elevations across the stringers. A roller coaster would not look nice for a deck. Use shims as needed and glue it all in.
Hatch Liner
Stock from the ribs was used to define the hatch to 6" wide and between stations 45 and 57. Glue was placed outside the liner for esthetics. Likewise, some 1/32 or 1/16" basswood sheet can be inlaid across 45 and 57 to hide the king plank before the deck sheet goes on. Then finish the liner interior to taste.
Aft King Plank and Rudder Hatch Liner
When the rudder linkage was installed, Station 76 was then lined for the access hatch. 2-1/2" from center was used as the minimum access here to provide overall esthetics.
The aft parts of the king plank were installed.
This completes the sub-deck work and the structure is ready for covering when all other interior work is done.