1) Millions and millions of Vanara Sena:
The vanara sena and bear sena are Millions and millions in number as per Valmiki Ramayana.
The number of ships required is in millions and thus not practicable!!
Valmiki Ramayana, Book IV : Kishkindha Kanda, Chapter [Sarga] 39:
Millions and millions of monkeys arrive with their troop-leaders to the control of Sugreeva. Rama's intent to wage war with Ravana is informed to Sugreeva. And Sugreeva who is interested for requital of the help rendered by Rama informs that all the monkeys on earth are ushered to remain in the service of Rama. While Sugreeva is informing about the arrival of monkeys, in a split-second that place is further crammed up with troops and troops of monkey-warriors.
Shatabali = ten thousand crores vanaras
Sushena = many thousands of crores of vanaras
Taara = thousand crores of vanaras
Gavaaksha = thousand crore vanaras
Dhuumra = two thousand crores of bears
Panasa = three crore vanaras
Niila = ten crores vanaras
Gavaya = five crores of vanaras
Dariimukha = thousand crore vanaras
Mainda and Dvivida = each with a thousand crore vanaras
Gaja = three crores of vanaras
Jambavanta = ten crore bears
Rumana = hundred crore vanaras
Gandhamaadana = ten thousand crores plus hundred thousand crores
Angada, the crown prince of Kishkindha = a thousand padma legions and a hundred shanku legions of vanaras
(Shanka = 10 to the power of 12,
Padma = 10 to the power of 32
(Valmiki Ramayana, Yuddha Kanda, Chapter 28, Verses 33 to 38)
2) Power of ten:
Dharmaakuutam commendary on Kishkindha Kanda, Chapter 39:
The count of the monkeys who followed their leaders cannot be rendered into million, billion counts, precisely. But when all of them are put together they result into the numerals as contained in Yajur Veda taittariiya as said in Dharmaakuutam.
‘eka dasha shata sahasra aayuta laksha prayuta kotyah kramashah |
arbudam abdam kharva nikharvam mahaapadmam shankhavah tasmaat ||
nidhih ca antam madhyam paraardham iti dasha guna uttaram samjnaah |
samkhyaayaah sthaanaanaam vyavahaara artham kritaah puurvaih iti ||’
3) The powers of 10 upto the power 17 have technical words in Sanskrit:
'Eka dasha shata sahsra ayuta laksha prayuta koti arbuda
Abja kharva nikharva mahapadma shankha jaladhi antya madhya parardha'
Eka = 10 to the power of 0
Dasha = 10 to the power of 1
Shata = 10 to the power of 2
and so on ................
Madhya = 10 to the power of 16
Parardha = 10 to the power of 17
(From Bhaskaracarya's 'Lilavat'
Dag aparardham = 10 to the power of 18)
4) Samudra Raja's suggestion & Nala's skil:
(i) Yuddha Kanda, Chapter 21 & 22:
The careless ocean did not appear in his personal form to Rama, even when it was requested to do so. Rama becomes angry at the ocean and looses fierce arrows, which cause a terror among the creatures inhabiting the sea.
When Rama is about to release a missile presided over by Brahma from his bow, the sea-god appears in person before him with joined palms and advises him to get a bridge constructed by Nala across the ocean.
(ii) Valmiki Ramayana, Yuddha Kanda, Chapter 22, Verses 43 to 47:
"........ Ocean the lord of rivers spoke these words to Rama who knew all scientific treatises."
"O, excellent man! This one, named Nala, a glorious person, is the son of Vishvakarma; who was given a boon by his father and is equal to Visvakarma."
"Let this greatly energetic monkey build a bridge across me. I can hold that bridge. He is just the same as his father."
Thus speaking, the god of Ocean disappeared from that place.
Then Nala said to Lord Rama,
"The great Ocean disclosed a truth. I will construct a bridge across this large Ocean, taking recourse to the skill and ability of my father."
(i) The water was not shallow in Ramayana times.
Valmiki Ramayana, Yuddha Kanda, Chapter 22, Verse 26:
Sea-God said to Lord Rama,
"Therefore, I am fathomless and my nature is that it is impossible of being swum across. It becomes unnatural if I am shallow. I am telling you the following device to cross me."
(ii) Poetic exaggeration assumption:
Poetic exaggeration is sometimes allowed in poems and even the number of army is in lakhs, the road march is the most effective way for attack.
The bridge was constructed in just five days according to Valmiki Ramayana (Valmiki Ramayana, Yuddha Kanda, Chapter 22, Verses 66 to 70).
The celestials and Gandharvas, the heavenly musicians saw Nala's bridge, having a width of ten yojanas and a length of hundred yojanas and which was very difficult to be built (Valmiki Ramayana, Yuddha Kanda, Chapter 22, Verse 74).
This shows the dedication of Vanara Sena and Rama Nama Mahima!
1 yojana = 13 km to 16 km