overy, in the Danish Royal Archives at Copenhagen, of
plans of this vessel, it is now possible to prepare a reconstruction and
to build a model._

_This article summarizes the history of the vessel, describes the plans
and the reconstruction, and also evaluates its design with particular
attention to the double-hull construction._

THE AUTHOR: _Howard I. Chapelle is curator of transportation in the
Smithsonian Institution's Museum of History and Technology._

The identity of the first steam man-of-war has been known for many
years, and a great deal has been written and published on the history of
this American vessel. Until recently, the only available drawing of the
ship has been a patent drawing made for Robert Fulton. This does not
comply with contemporary descriptions of the steamer and the drawing or
plan is out of proportion with the known dimensions. The lack of plans
has heretofore made it impossible to illustrate the vessel with any
degree of precision, or to build a scale model.

The discovery in 1960 of some of the plans of this historic ship in the
Danish Royal Archives at Copenhagen now makes possible a reasonably
accurate reconstruction of the vessel and also clarifies some of the
incomplete and often confusing descriptions by contemporary writers.

Of the numerous published accounts of the ship that are available, the
most complete is David B. Tyler's "Fulton's Steam Frigate."[1] A
contemporary description of the vessel by the British Minister to
Washington, 1820-23, Stratford Canning, was published by Arthur J.
May.[2] In _Naval and Mail Steamers of the United States_, by Charles B.
Stuart,[3] and _The Steam Navy of the United States_, by Frank M.
Bennett,[4] the history of the ship and some descriptive facts are
given. Stuart, in an appendix, gives in full the report of the
Supervisory Committee (set up to administer the building contract).
Tyler and Stuart, and the Committee Report are the principal sources
from which the following summary of the ship's history is drawn.

[Text of Illustration: Plate N^o. 1.

"DEMOLOGOS"

Figure 1^st. _Transverse section A her Boiler. B the steam Engine. C the
water wheel. E E her wooden walls 5 feet thick, diminishing to below the
waterline as at F.F draught of water 9 feet D D her gun deck_

_Scale 1/12 inch=1 foot_

Waterline

_Scale 1/24 inch=1 foot_

Figure II^d. _This shews her gun deck, 140 feet long 24 feet wide,
mounting 20 guns. A the Water w