I'm making a boat out of an old aspen tree trunk. Any tips or something. For example I'm not really sure if or how to waterproof it. I already tried it in water and it kinda worked, but the water line was too high (I will fix it by doing more hollowing). I'm set for sail in four days and I need it to work only for a week

I'm making a boat out of an old aspen tree trunk, any tips or something. For example I'm not really sure about water proofing. Is it really that important if i want to only use the boat for one week. I already tried it in water and it kinda worked, but the water line was too high