There are so many ships sank in that part of the world, do you have any pictures of the cannons and anchor. Are the cannons iron, if so put them back in the water along with the anchor or before long you will not have anything left to look at.
Is there any markings on the cannon?
Photographs please.
Here is another thing to look.
Ilha do Fogo Light, Mozambique.
This spectacular skeletal lighthouse was built in 1926 on the Ilha do Fogo, an island off Ponta Matirre northeast of Macuse on the central coast of Mozambique. At 37 meters (131 ft), it was one of the tallest African lighthouses of this type. Most likely it was prefabricated in Europe for assembly on site, but we know nothing of these details. Sadly, it probably does not survive. The modern light on the island is 34 meters tall (111 ft) and is described as a "quadrangular skeleton tower." Other lighthouses of similar description in Mozambique are constructed of prefabricated reinforced concrete beams.