I have never understood why someone would subject their life and limb and all the work thats involved in these project to building a paper mache boat. If you want the boat to last a wee bit of a time and hopefully passing it along to another family member or even give it away, don't you want not to worry about potential problems that may creep into the equation? If you are worried about the cost of fiberglass tape, then you should not be building a boat that requires it, especially given the cost of epoxy resin if that is what you plan on using to wet the drywall tape out.