A SMALL IRON CANNON RECOVERED FROM SAN DIEGO BAY
By James R. Moriarty and William L. Crocker* , *The University of California at San Diego
In January of 1947 a small cast iron cannon was recovered from the sunken remains of an ancient wooden sailing vessel. (see fig. 1) The cannon is now at the Jun�pero Serra Museum. In January of 1965 the author and his assistant were requested to research the probable origin of this small piece of ordnance and prepare a detailed report of their findings. It is hoped that this report will reach others who have information about similar discoveries.
Until the end of the 17th Century cannon were known by a number of exotic names such as bastard, shaker, falcon, serpentine, etc. Standardization in the 17th Century reduced the number of types manufactured, and cannon were classified by the weight of their projectile. By the close of the experimental period in heavy artillery (late 1500's) iron as well as bronze and brass were all being cast to make ordnance. Iron was more subject to corrosion than either bronze or brass, and, was liable to fracture dangerously. Its advantages for smaller cannon were great enough, however, to outweigh the foregoing. Iron was cheap and could withstand rough service. Small pieces could be cast heavy enough to reduce the possibility of fracturing. Small cannon, such as wall guns, were made to load at the breach until the 1550's. Breech loading, though, proved extremely impractical due to the existing knowledge of metal working at that period. By the early 1600's cannon were almost exclusively muzzle loaders with the length of the gun controlling the size of the smooth bore. (see fig. 2)
There were three basic problems in the method of manufacturing cast iron cannon. First, a new mold had to be made for each gun as the techniques of bronze founders were employed by the iron founders during the 1600's. Secondly, impure and highly carbonized iron was poured into the mold and as the metal received no further treatment the cast tended to be weak and brittle. Third, early iron cannon were cast over a prepared cylinder of clay which created a rough bore. This was then reamed out and the gun, as a consequence, was often very erratic. Each cannon's idiosyncrasies had to be known by the gunner before he could lay the gun accurately enough to hit the mark. The Dutch are credited in 1747 with beginning the general practice of boring out solid cast guns. Hollow casting was still in general use in England, France and Spain until after 1770.
There are many references relating to the use of muzzle-loading cannon during the early days of the Spanish occupation of Baja and Alta California. One of the earliest is to be found in the log of The Voyage of Francisco de Ulloa in 1539.
"Seeing that we delayed, the natives fired a few arrows at the ship ... but not satisfied with this, many of them waded waist deep into the water to fire arrows at certain sailors who were in a boat raising an anchor. . . ."
"In view of this and of the bad treatment we received from them the first time we arrived here2 . . . and also in order to protect the men in the boat, I decided to let them have some punishment. . . in consideration of their conduct, past and present. We let loose on them a few shots3 from the ship, which did some damage, and would have done more, but, thinking that the skies were falling on them, upon hearing the shots and seeing some fallen among them, they fled in a fashion worth seeing! . . . "
Cannon played an important role in the protection of the first fortified structures at San Diego. Upon the arrival of Captain Rivera y Moncada, in 1769, he began construction of a stockade at the newlyestablished camp. The cannon he utilized were small bore, muzzleloading, swivel guns which he removed from the bulwarks of the San Carlos. (see fig. 3) As we have said elsewhere, this type of cannon was not always dependable. Indeed, it was extremely dangerous both to the defender as well as to the aggressor.
Shortly after the establishment of the Mission of Our Lady of Loreto in Baja California, an Indian uprising brought into play a small cannon which exploded at the critical moment and nearly caused the destruction of the Mission. This was a small swivel gun mounted on a mesquite stump. On November the 12th, 1767, the little garrison at Loreto was attacked by four band of Indians. They were surrounded, the captain estimated, by about 500 Indians. The gunner fired in an attempt to frighten them with a few well directed shots from the swivel gun. The breech exploded, knocking him down and seriously wounding him. The Indians, observing that none of their number was hurt, grew confident and assaulted the stockade from all sides. The soldiers fired a volley with their muskets. A number of Indians were killed and wounded; the rest fled and the garrison was saved.
The small cannon recovered from San Diego Bay was a hollow cast, muzzle loading, swivel gun (bow or stern chaser). (see fig. 3) It was manufactured from a highly carbonized and very brittle cast iron. Due to its long submergence, corrosion had removed all identifying marks including muzzle or barrel roundels. Only one of the trunnions still remains in part. (see fig. 1) The ball of the cascabel is totally reduced so that only the necking remains. Investigation of the first reinforce showed the touch hole or fire aperture to be completely filled with fine oxidation. The angle of aperture appears to be approximately 15' from a vertical line projected perpendicular to the bore. Diameter of the bore is 1.75 inches. This would allow for a ball of approximately one pound.
GENERAL OVERALL DIMENSIONS
Cascabel, ball diameter 2", length 2.75"
First reinforce, length 5.25"
Second reinforce, length 10"
Chase, length 17"
Swell of muzzle, length 3"
Base of breech, diameter 7"
Fire aperture, diameter 3/8", angle approximately 15'
Chamber, and bore, diameter 1.75"
Trunnion, diameter 2", length 3"
Bore at muzzle, 1.80"
After careful examination it was determined that the Serra Museum cannon was probably manufactured sometime prior to 1770. As the life (i. e., in the sense of its use) of such a piece of ordnance was probably as much as 50-75 years, or longer, it seems reasonable that the cannon found its way to the bottom of San Diego Bay within the first fifty to seventy-five years after the establishment of the Royal Presidio of San Diego. A cannon of this size and type was probably used as bow or stern chaser on one of the supply vessels, which from time to time, arrived at San Diego during the early Spanish occupation. Such small guns were often used for line casting and saluting, as well as fighting.
They were mounted on a u-shaped stirrup which was attached to a pivoting bar (see fig. 3). The recoil of these cannons was negligible. This was due to the fact that the weight of the gun was more than enough to compensate for the explosive recoil of the powder charge. Additionally, black powder was used which is relatively slow in detonating when compared to modern cordite or smokeless powder. Taking into consideration the amount of surface metal loss due to corrosion, a good estimate of this cannon's original weight would be close to 150 pounds.
A number of points to be considered in determining the general age of this piece have to do with the environment in which it was found, its type and style, and the fact that examination disclosed that the piece was still charged with a small round shot. Information taken from the finder indicated that the cannon was recovered from the wreck of a very old vessel lying in the relatively shallow waters in what is known to have been the primary anchorage used by the early Spanish. The informant stated that the curved ribs of the hulk were still discernable. Only a careful underwater investigation can add more weight to the probability that this indeed is an early Spanish ship.
There is no question in the mind of the authors that this is an early piece of Spanish ordnance. All of the available references show that the cannon must have been made sometime in the late 1700's. Finally, there is no reference to any vessel (known to the authors) having sunk at or near this anchorage excepting for two references to a Spanish vessel which went down at a very early period. We are at present investigating these references.
In conclusion it should be noted that one other piece of evidence is also in existence. Near to the point where the cannon was recovered another informant found a small hand-wrought iron anchor. It is generally accepted that this anchor is related to the earliest period of Spanish occupation. Considering the close association of these two objects (i. e., the cannon and the anchor with the wreck) it is well within the realm of possibility that both are from the same vessel.
A careful examination of the bottom by scuba diving by the Scripps archaeological divers is being planned. We hope to be able to discover the answer to the mystery of the cannon and anchor sometime this year.
1. Henry W. Wallace, then Chief Warrant Officer, now retired was skin diving in San Diego Bay for recreation. He brought the cannon to the surface, and then took it to Texas. When he returned to San Diego he gave the cannon to George Stollard a Chula Vista fireman who in turn gave it to Larry Areingdale also a fireman of Chula Vista. Through his interest the research and study on the cannon was made possible, in turn leading to the restoration of the piece for exhibit.
2. This incident took place at Punta de la Trinidad, on the east coast of Baja where they had previously watered.
3. Spanish -- versos, a small cannon in use at that time.