Gyani Jarnail ji

There are some puzzling things in Sidh Gosht. These lines raise some questions for me.

dunIAw swgru duqru khIAY ikau kir pweIAY pwro ]
dunee-aa saagar dutar kahee-ai ki-o kar paa-ee-ai paaro.

Reference:: Sikh Philosophy Network http://www.sikhphilosophy.net/sidh-gosht/5309-sidh-gosht-gurumukhi-script-english-transliteration.html
"The world-ocean is treacherous and impassable; how can one cross over?

crptu bolY AauDU nwnk dyhu scw bIcwro ]
charpat bolai a-oDhoo naanak dayh sachaa beechaaro.

Charpat the Yogi says, O Nanak, think it over, and give us your true reply."

Awpy AwKY Awpy smJY iqsu ikAw auqru dIjY ]
aapay aakhai aapay samjhai tis ki-aa utar deejai.

What answer can I give to someone, who claims to understand himself?

swcu khhu qum pwrgrwmI quJu ikAw bYsxu dIjY ]4]
saach kahhu tum paargaraamee tujh ki-aa baisan deejai. ||4||

I speak the Truth; if you have already crossed over, how can I argue with you? ||4||
Reference:: Sikh Philosophy Network http://www.sikhphilosophy.net/showthread.php?t=5309

It sounds as if Naanak is saying to the yogi -- if you have already crossed over, how can I argue with you? Charpat the yogi has asked how does one cross over the world ocean, he says that it is treacherous. Who is it that Naanak will not argue with? I am thinking that Naanak himself has crossed over the world ocean and does not want to be drawn into a guessing game. It is almost as if he is saying: If you Charpat had crossed over the world ocean, you wouldn't be asking me these questions. Naanak has a different message, a diferent point of view.

But I am missing something. What is your understanding?

Thanks in advance. And this is a great topic for the forum. I have other questions, but can wait.