Fiberglass is actually very flammable.
No. Once fiberglass is set, it cannot be altered.
I think it is arounf 9w/m2k
Sears Gamefisher 14' Tri Hull Fiberglass Boat
On a South Bay pontoon boat, the hull number, or Hull Identification Number (HIN), is typically located on the transom, which is the rear part of the boat. It can also be found on the starboard side, usually stamped into the fiberglass or on a metal plate. For precise location, it's best to consult the boat's owner manual or check with the manufacturer.
Fiberglass does not adhere well to PVC, which is commonly used in inflatable boats, as the two materials have different properties and chemical compositions. While you could technically layer fiberglass onto the bottom of an inflatable boat, the bond may not be strong enough to create a rigid hull, and it could lead to delamination or separation over time. Additionally, the added weight may affect the boat's performance and buoyancy. It's generally not recommended to modify inflatable boats in this way.
A sailboat whether it's single hull (one hull) or a multi-hull (more than one hull) can be made of different material. The majority of today's sailboats however are made from fiberglass. This is mainly because fiberglass is strong, can absorb shock (to a certain extent), is relatively cheap to make (compared with other materials such as wood) and is easy to make a mold out of.Some of the older sailboats are made from wood and some are also made from steel. There are both pros and cons to this as wood and steel are heavier than fiberglass and therefore take more energy (wind, fuel etc) to move the boat along.
Fiberglass.
The hull on a boat is the body of it. It is watertight so that no water leaks in and sinks the boat.
You can learn how to repair hull holes in fiberglass boats here: http://www.boatus.com/boattech/casey/17.htm
use somegoof-off or paint thinner or gasoline
On the hull