When I arrived at the pier in the jungle the top on the back of the Hydroflot is not there. I went and got the jerrycan and map, I refueled and took off, without the top on the back. When a buffalo hits me I'm suppose to hit Grapnel Mode. Nothing shows up, no hand or arrow, so I can't hit on anything. Has anyone else had this problem? Is there a patch I don't know about. Any help will be appreciated.

This is what the official strategy guide from Dreamcatcher says:

WARNING - SPOILER!!!
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You said you had refueled, so I'll start from there.

Further along, your way is blocked by 2 water buffalos. Try to go forward using the forward arrow through your windscreen. One of the water buffalos will attack the hydrafloat (ie, boat) and damage the engine. (I placed the forward arrow on the window [what the manual calls the windscreen] in front of me, just above the boat's console.)

Turn to the left of the windscreen and click to turn the craft. You now have access to the console again. At the display, select grapnel. It will go into active mode. Your cursor icon will turn into a grappling hook.