King Pinklao became the country's first admiral after his investiture and remained in that capacity until he died. He was considered to be the man who laid the foundations of the Navy, raising it to international standards.
Admiral of the Fleet Attacking Bantaimat
In the beginning of the year 1851, he began to show his competence in naval affairs. Thailand had been at war with the Vietnamese for several years. King Nungklao appointed him Admiral in charge of the fleet to attack Bantaimat (Ha Tien ) while he was Prince Isares Rangsan. This was a tactic to divert Vietnamese attention so that the army could fill up the canal, cutting supply and communication lines to prevent them from setting in Cambodia. In the battle, the Thais had to retreat as the Vietnamese fought fiercly.
The Wang Na Navy
Having established the Wang Na Navy after his investiture, King Pinklao continued to develop and maintain it. Buildings were constructed on the banks of the Chao Phraya river, the present site of Thammasart University. In addition, the Prince transformed two merchant ships into men-of war, naming them Asawadirot and Yongyot Ayochiya.
Phikat Khasuk Fort
In 1838 King Nangklao entrusted his younger half brother, Prince Isares Rangsan with the construction of Phikat Khasuk Fort to guard the mouth of the Mae Klong River at Samut Songkhram province. This was the Prince's first official duty recorded in the Royal Chronicle.
Vietnamese Volunteer Division
During the reign of King Rama III, the Vietnamese migrated into the country three times. During the second migration in 1838, many who came, were Christians. The King separated them from the Buddhists and had them settled in Samsen area. He had Prince Isares Rangsan train them for the artillery.
During the third migration in 1850, the migrants were Buddhists. The King had them settled on Bang Pho as the Vietnamese Volunteer Division under the command of his brother, Prince Isares Rangsan to man the artillery at the fort.
Commander of Artillery Men and Foreign Forces
The Prince was commander of the artillery men and foreign forces and devised millitary drills in the western style. He adapted and organized artillery science along the European pattern in terms of strategy and tactics. The cannons used were locally cast iron; the uniforms were like that of the Sepoy.
An Artillery Manual
In his capacity as superintendent of the artillery drill and the commander of the artillery, The Prince needed a text for drilling so he wrote a manual in 1851. He translated English books on the western use of artillery, modern tecniques for gun casting, and firing. He also added Thai folklore and beliefs he had collected, such as a directory of cannon names, secret tactics and magic. The text was originally used in training the Vietnamese artillery and was used by the artillery until the manuscripts written in color ink by royal scribes appeared during the fourth Reign.
The Layout of Chareonkrung Road
A story circulated that the Prince, an artillery expert, raised an objection to the original plan of Chareonkrung Road which would go straight from Sam yak to the city making the city gate vulnerable. It would be an easy target if an enemy brought cannons on the road, therefore the road was built curving towards Damrongsatit Bridge, making a sharp angle with it.