Was the ark protected by dolphin leather? That depends on which ark we're talking about! Genesis 6:15 [NLT] says Noah's was 450' long, 75' wide, and 45' high. It was made from cypress [NIV] or gopher wood [KJV] and sealed with tar inside and out [Click here for some pics of Noah's built to half scale by some Dutch guy in Holland]. The Ark of the Covenant [a sacred chest not a boat] 3¾' long and 2¼' wide and 2¼' high was much smaller—though anything compared to Noah's would be!!! Exodus 25:10-22 says it was made from acacia wood [NIV] or shittim wood [KJV—insert joke here] and covered with gold.
But what startled me recently was that Exodus 26:14 says the big tent covering that ark was made of sea cows [NIV]. Which according to Rabbi Dr. Louis Jacobs (1920-2006), a leading writer and thinker within Conservative Judaism before he died, is a word of uncertain meaning often translated "dolphins."
Why would God encourage people already on a quest to undertake another quest to find, capture, kill, skin and eventually tan some dolphins while they're in the middle of the desert? Whether you think they actually did this or not, isn't it a good thing to remember that a mission from God always lead to motion? What quest do you hear God sending you to pursue? If apart from Christ we can do nothing [John 15:5], who should get the credit in any of "our" exploits?