HMS Warrior 1781

March 29, 2007

Vol. 1, Keel Discrepancies

Filed under: — admin @ 9:00 am

After studying and comparing the plans over a lightbox, I have several discrepancies between Hahn and supplementary Romero plans. My Hahn plans and their enlargements are correct to scale. This can be verified by making 1″ horizontal and vertical marks on each page of the Hahn plans prior to copying to 3/16″ scale (150%). After enlarging, these 1″ marks should measure 1.5″

Keel Discrepancies

Looking at Romero’s keel plan there is a problem, the keel in the top view measures 29-3/16″, in the side view it measures 29-1/4″, when measure on the Hahn plans the keel measures 29-1/8 inches. The importance of this is debatable as any extra keel length can be trimmed, where it may be problematic is in accurately tapering the last keel piece over the correct length to 3/16″

Hog Discrepancies

Romero’s hog piece is 1/4″ longer than Hahn’s and I suspect his supplementary keel plan is incorrect in this respect, I do not know if this is due to a problem with his drafting or his reproduction of the plans – he does not provide scale markings on it to measure. It may just be my copy, but the 1/4′ discrepancy over the full length of the hog would throw the frame alignment off enough to be noticeable I believe. The hog/boxing alignment pages from the practicum (p. 195-8) are much closer in correctness to the Hahn plans and are only about 1/16″ longer. When laying these over the Hahn hog you can see where the discrepancy is located. Beginning at frame 8 on the Hahn plans the “notch” is not 3/16 as it should be but a little bit narrower, we see the problem again at frames 9, 10, F, 11, G, H, 15, and 31. At most the notches are too narrow by somewhere between 1/32″ and 1/64″. I’m not sure this would be noticeable over the length of the ship if one was to use this layout. The Hahn plans appear to be hand drawn and as such these errors can appear. Romero’s layout from the practicum features consistent and regular spacing of the notches and hog pieces and in essence is more correct. However, the Hahn hog matches up to the framing jig better. In order for everything to be absolutely true to the framing jig, you must use the Hahn hog and at certain points make the boxing pieces narrower to accommodate the frames correctly with a perhaps slightly closer interval between those frames or use the templates from the practicum and accept that a few of the frames my fall slightly off of 90 degrees. Either way, I’m not sure either would be noticeable. I do believe though if I were to use Romero’s supplementary keel plan for the hog then the discrepancies would definitely be noticeable – again that my just be an error in the reproduction of my plan.

Romero responds

Whenever the Practicum differs from the Harold Hahn plans, choose the Practicum. There were a few minor changes made since the spacing of the center line frames on Hahn’s plans are not even, and these are translated over to the enlargements. Also do not be concerned with the length of the keel on the composite drawing. The pattern is not exact as regards the length. When you fit the last frame on the keel, and then add the stern deadwood and stern post, that’s the time you remove any excess keel length. Actually, the Warrior is a hair larger than the Alfred, but when you place the frames on the keel, again, simply insert them in the master jig plan of Hahn’s construction board. It will not be noticeable if the frames are slightly out of vertical, as a large portion (especially in the waist area of the ship) of the frame tops will eventually be cut off, after the hull is planked above the wales, and in this case, you will not notice the spacing between the frames. Keep in mind that the weight of the paper used in the Practicum books is 70 pounds, and the paper used in the blueprinting firm is much less. I know the blueprinting enlargement is accurate, but I would still trust the heavier weight of the book paper. You might wonder why I made the keel not the exact length on the composite drawing? The answer is to allow for some minor adjustments as regards the thicknesss of the frame wood stock. There might me some variations in the stock of one billet from another, but the important thing is to maintain as much as possible the spacing between the frames. I hope this helps you. Bill

What to do

I believe the practicum hog boxing alignment from page 195-8 is the most accurate for laying out the boxing pieces and is preferable to the Hahn plan.

The supplementary keel plan should not be used as a template for the hog.

The supplementary keel plan is absolutely fine as a template for laying out the apron/stem/knee, the stern deadwood, sternpost and building the keel. The final keel section (#6) should be tapered over the pattern length to 3/16″, once the hog, deadwood, and stern post are installed, it can be trimmed and the tapering adjusted.

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