Invincible, a Texas Navy schooner

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Building the Invincible, a Baltimore clipper, Part 1
This is a build history rather than a build log since the model was completed in 2019. It will not be a detailed step-by- step account, but instead I have just outlined some of the methods that have served me well in scratch building plank on bulkhead models. This is my first attempt at posting to this Forum, so I will take it a bit slowly and do it in parts.
Invincible History
In October, 1835 colonists in Texas started a rebellion against Mexico to form their own state. Shortly afterward, the Provisional Government, recognizing the importance of protecting the coast, authorized the formation of a Navy which was born in January 1836. The fleet consisted of all of four vessels, three purchased schooners and and a former U.S. Revenue Cutter ( More information on Texas Navy history can be found on the web site of the Texas Navy Association. ). One of the vessels, the schooner Invincible, was of particular interest as a model for display at the Houston Maritime Museum since a search is currently underway off Galveston for her wreckage, and I agreed to build the model.
Hull Design
Although no plans exist for this ship, original purchase documents indicate that she was built in Baltimore, probably as a slaver, at the yard of John A. Robb, and had the dimensions 66'3” length on keel, 83'8” length on deck, 21' beam, 8' depth and 126 tons. Invincible was most certainly a Baltimore clipper design. The total cost in 1836 was $20,000: $12,613 to the Robb shipyard and about $7,400 for fitting out.

Robb was a prolific shipbuilder with a long career and the subject of a detailed biography by G.M. Footner in the Nautical Research Journal (Vol. 50, No. 3, page 130, 2005 ). In this article Footner provides the plans of another Robb designed Baltimore clipper, smaller than Invincible at 75' length and 19' beam. In Howard Chapelle's book, “The Search for Speed Under Sail “ (Bonanza Books) , he presents (page 294 ) a plan for the the Isabella, which has very similar dimensions to the Invincible, the only significant difference being a 19' breadth as compared to a 21' breadth. A comparison of the plan for the Isabella with Footner's plan of a Robb schooner indicates very similar lines so it was decided to base the Invincible model on the Isabella since the dimensions are so similar. Only the deck arrangements were altered to match what was known about the Invincible.

The armament on the Invincible at commissioning is known from the original documents and consisted of 4 cannon on each broadside ranging from 4 to 6 pounders and an 18 pounder central pivot gun.
Masting and Rigging
Mast and spar dimensions were based on data for the Robb designed schooner Allicope (C. Cozewith, Nautical Research Journal, Vol.63, No.2, page107, 2018) which was similar in size to Invincible. The schooner rigging plan in Petersson's “Rigging Period Fore and Aft Craft” (Naval Institute Press, 2007) was the primary source for this model. Determining rigging sizes is usually a challenge for a scratch builder. I utilized the tables in Biddlecombe 's “The Art of Rigging” (Dover Publications, 1996) for some of the lines and the rest were estimated from the rules of thumb in Lee's “The Masting and Rigging of English ships of War, 1625-1860” (Naval Institute Press, 1979) which allows calculation of line sizes if the mast dimensions are known.
Construction
Invincible was built by the plank on bulkhead method at a scale of 1/50. The Chapelle plans were enlarged on a copying machine to give the desired model dimensions.
Figure 1 Keel Piece and Bulkheads
The lines of the sheer plan were altered as follows to make a template for the keel piece:
1)The line for the underside of the deck was lowered by 1/32” to account for a sub-deck on the model.
2) Slots were indicated for the masts
3)Temporary extensions were drawn at the stern to help shape the curve of the transom and at the bow to support the ends of the bulkhead planks.

A bulkhead template was made for each station on the body plan. These templates were lined up with the shear plan to establish the location of the deck at the centerline, and a cambered deck line was then drawn on each bulkhead template. The templates were glued to 3/16” aircraft plywood for keel piece and bulkhead construction.
Figure 2 Frame Assembly
Before inserting the bulkheads into the keel piece, holes were drilled in the bottom for later attachment of the pedestals and slats were glued on each side of the masts slots to insure proper mast placement when they were inserted. Note in Figure 2 some wood has been removed at the stem rabbet line so the plank ends will lie flush with the keel piece.
Alignment was checked by making sure the waterlines on the bulkhead templates lined up with the waterlines on the keel piece during dry fitting. After alignment adjustment, the bulkheads were glued in place then faired. Next, filler pieces were made and glued in forward of the first bulkhead and aft of the last bulkhead to support the ends of the hull planking.

The next step was to cut out a sub-deck from 1/32” aircraft plywood. Prior to installing it, the location of the deck edge was marked on the outer edge each bulkhead and a notch was cut into the bulkhead for a 1/16” x 3/32” stringer. The stringer was test fitted to give smooth curvature of the deck from bow to stern and then glued in place. Finally, the sub-deck was glued to the top of each bulkhead and the stringer. This will insure the proper shape for the deck.

The model received double planking of 1/16” basswood followed by 1/32” cherry. Plank maximum width was 3/16”. A decision for the modeler is where to start planking. I usually choose to put the first plank either at the wale or right below the gun ports where it can serve as a reference for later measurements on the hull. For the Invincible, the first plank was at the wale.

Figure 3 Planking Scheme
There are many different well documented approaches to planking. I'm sure that my procedure is similar to many others. I first measure the perimeter of the dead flat (widest) bulkhead below the wale and divide by the plank width, in this case 3/16”, to get the number of planks needed to cover the hull from the wale to the keel. Marks are then placed on the dead flat bulkhead corresponding to bands of 4 or 5 planks (3/4” or 15/16”) and battens are tacked on just below these marks. The battens are then adjusted by eye to give fair plank runs with the requirement that the width of a band at the stem be no less than ½ the width at the dead flat bulkhead. When satisfied, the battens are then tacked to each bulkhead and their position marked before they are removed. Starting with the uppermost band, the perimeter along all of the bulkheads is measured from the wale to the first batten marks and divided by the number of planks in the band. This quotient is multiplied by the plank width to get the width needed at that bulkhead. The planks are then tapered accordingly and glued to the bulkheads and to the edge of the plank above. The same measurement and tapering method is used from band to band.

Figure 4 Lower Planking and Bulkheads

For the final band, I put the garboard on first and planked upward to complete the lower planking. No stealers were needed for this particular hull which had very gently curved lines. Lastly the bulkhead area is planked up from the wale to the sheer. This region of planking requires little tapering and usually presents no problem.

1bulkheads.jpg2first planks.jpg3planking battens.jpg4planking process.jpg
 
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Building the Invincible, Part 2
Figures 5, 6 and 7 Cherry Planking
The above procedure was repeated for the second layer of cherry planking.
Figures 8 and 9 Transom and Stern Planking
Filler blocks were placed on deck at the stern to provide support for shaping the transom which was made from 1/32” plywood. The large nails shown sticking up are in oversize holes and hold the blocks in place temporarily. The transom was then added and planking completed at the stern, after which the fillers were removed.
Figure 10 and 11 Completed Planking
The stubs of the bulkheads were sawn off above deck and a layer of cherry planking added to the inside of the bulwarks and transom. Aircraft plywood, 1/32” thick, was sawn into 1/8” wide strips for planking the deck. A waterway was installed on the deck followed by deck planking. Finally a cap rail was added, The fore part of the rail was sawn from a sheet of cherry as the curvature was too great for a bent plank. In the photo it appears prior to fairing. A decorative molding was added to the transom.
Figure 12 Completion of the Hull
Addition of molding, staining with Minwax natural finish, and then painting with satin polyurethane varnish completed work on the hull. After the varnish dried, a matte finish was obtained by rubbing the hull and deck with double zero steel wool.
The rudder was the next item added to the hull. I did not take any photos of this area, but the only technique worth mentioning was making gudgeons and pintles. I bent a brass strip into a U-shape, drilled holes in the legs (usually with a #74 drill bit) for nails, and then soldered a piece of 1/16” diameter brass tubing to the bottom of the U for the rudder pins. After cleaning up excess solder, the pieces are painted black with pearl noir (see below) to simulate iron.

5start of cherry.jpg6second planking.jpg7 completed planking .jpg8stern transom support.jpg9stern planking.jpg10completed planking.jpg11stern.jpg12deck and moldings on.jpg
 
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Building the Invincible, Part 3
Figure 13 Pivot Gun
Next in the building process was to install the deck furniture. The first feature completed was the broadside guns since there was plenty of working space to add the numerous eyes and blocks to the bulwarks. Gun carriages were scratch built, but all of the cannons were purchased form the Lumberyard for Model Shipwrights which has a wide selection of very well made cannon barrels. The barrels come blackened, but it is not durable and easily rubbed off. I removed the blackening with steel wool and painted the cannon with pearl noir acrylic hobby paint available in stores like Michaels. When an iron appearance is needed for a fitting, this gives a metallic look as compared to ordinary black paint.
The major feature on deck was the 18 pounder pivot gun. Just as I was puzzling over how they were built and rigged an article By Colin Ratliff appeared in the Nautical Research Journal (Vol. 62, No. 1, Page 17, 2018 ) on this subject. I used the photos in the article as a guide for building the carriage and track for my pivot gun. The track was made from a section of 2” PVC pipe.
Figures 14, 15, 16 Deck Furniture
The remaining deck furniture (hatches, bitts, winches, etc.) were next added to the deck.
Figure 17 Ship's Boat Construction
I made the boat for the Invincible by the plank on bulkhead method with the following modification. Three holes were drilled along the length of the keel piece to accept pins. After the slots were cut for the bulkheads, the keel piece was very carefully sawn into two pieces starting in front of the foremost bulkhead, continuing just above the rabbet line of the keel, and then up the stem to the shear. Pins were then inserted to rejoin the two pieces and the bulkheads were glued in place to the inner section of the keel piece. The transom was added as well as a filler block at the bow to the outer section. The boat was single planked. Planks, 1/32” thick cherry, were wetted and bent to shape with heat so they would lie flat against their respective bulkheads. Starting at the garboard, which was glued at the keel, bow and stern, the boat was planked upwards with each plank glued only at the ends and along the edge to the plank beneath it. If needed, a nail was inserted to hold a plank tight to a bulkhead while the glue dried.
When planking was complete, the pins were pulled out and the upper part of the keel piece with attached bulkheads could be removed. The boat was then fitted out with ribs, thwarts, etc. and hung from the davits at the stern.

13pivot gun.jpg14deck funiture.jpg15bow view.jpg16aft view.jpg17ships boat.jpg
 

zoly99sask

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Interesting project, I will follow your progress.

Here is a little help how to post full images, I fix the first to post

14F50C1A-2AD4-403C-B2E5-3103D574FFD9.png
 
Joined
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Messages
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Building the Invincible, Part 4 (The End)
Figure 18, 19, 20 Rigging Progression
Shown in the final three photos are the standing rigging on the lower masts, partially finished running rigging, and the completed model.

18Lower stanfding rigging.jpg19 RiggingI.jpg20completed model.jpg
 
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