Hull Construction

The drawings of Bounty *s hull in this book are based on two sets of contemporary draughts; the first was prepared to illustrate Bethia for the Admiralty, and the second, based on the firsts to show proposed changes. The first draught is dated 25 June 1787 and shows Bethia as she was purchased; the second* dated 19 November 1787, embodies the modifications required by the Admiralty, and was used by Deptford Yard. Both sets of drawings show an outboard profile, half breadth plan and body plan on the first sheet and plans of the upper deck, lower deck and hold on the second sheet. As no major structural changes were made> the half breadth plans and body plans are identical on both sets. The drawings were prepared at a scale of lA inch to the foot (}A% scale) and as paper is prone to shrinking and expanding it is fortunate that the draughtsman provided a linear scale to both outboard profiles.

Both draughts have an outline specification giving dimensions and tonnage, and here there is a contradiction. The specification dated 25 June reads:

Length of the Range of the Deck 85ft IVim

Do. of the Keel for Tonnage 69ft ll3>6in

Breadth Extreme 24ft 4in

Burthen in Tons 220 26 M

The Specification dated 19 November reads:

Length of the Range of the Deck 84ft 6in

Do. Keel for Tonnage 69ft 9in

Breadth extreme 24ft lOin

Depth in Hold lift 4in

Burthen in Tons 228 64/94

The difference between specifications is easily explained: just prior to acquiring Bethia the Deptford yard officers surveyed her and produced the early figures; they produced the second set after docking her and examining her more closely* It is therefore a safe assumption that the specification of 19 November is the more accurate, and indeed Bounty's lower deck length (fore perpendicular to aft perpendicular) scales 84ft 6in. Her tonnage was calculated by the formula:

length of keel x breadth x Vz breadth

Bounty's draught shows a total of eleven station lines expressed as frame lines on the body plan. These are the Dead Flat, A to D forward and 1 to 6 aft. These lines were probably determined by the Deptford Yard surveyor, by taking internal measurements (to the outside of frames) and while they give enough information for a draughtsman to describe the ship's hull shape on paper, there are not enough of them for a shipwright to build a vessel. I arrived at Bounty's framing plan by laying out the given station lines, from the draught, and assigning further lines at 4-foot intervals; these are the Dead Flat, (A) to O forward, and (3) to 24 aft, (The bracketed frame numbers occur amidships where all frames are identical to the frame at the Dead Flat), This system works perfectly if one allows that the surveyor took some measurements on the fore face of the frames and some measurements on the aft face, and that it was not essential that the frames he chose coincided with the original builder's lines. Based on 4-foot frame line intervals a room and space dimension of 12 inches is produced, the frames being 10 inches thick and spaced 2 inches apart, I have shown the original builder's lines circled on the half breadth plan and the framing plan.

As stated above, Bounty's principal dimensions were given to the Navy Board on 23 May; these dimensions are very straightforward and the draught reflects them almost precisely. The sizes of the upper deck beams and hold platform beams can also be determined from the draughts, as well as details of stem, keel and stern post and the size of the mast steps. From here on assumptions must be made based on ship-building practices of the day (see Table 1).


Gunwale External plank Wale

Strake above wale Limber strake Keel

Sole plate



Boating Secrets Uncovered

Boating Secrets Uncovered

If you're wanting to learn about boating. Then this may be the most important letter you'll ever read! You Are Going To Get An In-Depth Look At One Of The Most Remarkable Boating Guides There Is Available On The Market Today. It doesn't matter if you are just for the first time looking into going boating, this boating guide will get you on the right track to a fun filled experience.

Get My Free Ebook

Post a comment