Ok, something I know a little about. Dry wood will
NEVER ROT, NEVER!!!!!!!! Just in case you didn't see it
DRY WOOD WILL NEVER ROTT!
Like mentioned above, rot in wood is cause by a fungis, you have brown and white fungi. But the root cause to rot is the moisture to begin the process!! Without moisture to begin the process, you will never have rot. There is also no such thing as dry rot. People refer to alot of rot as dry rot because once they find it, it is dry. If it was rotten, it was wet at some point. Rot is caused by moisture,plain and simple.
Rot in boats is absolutely no different than wood rott in homes, trees, musical instruments etc.
How many times have you seen a nice pretty tree that is about to fall down because the base or core of the tree is rotten? Its because the base of a tree sits in moisture all the time. The rest of the tree will be just fine because it has air flow that does not allow the tree to be infested with fungi. Fungi needs over 20 percent moisture to sustain growth.
Here is another example, poles driven into the river for dock building will last 50 or 60 years in some cases. The only rot you will see in them is from where the water was allowed to protrude down into the tops of the poles making them useless in short time if not sealed properly. Other poles get damaged below the water line by debris and current contantly wearing them down.
If your confused about what seems like to contradictory statements above, fungi, atleast the rotting type that "eats" wood can not live under water. Fungi only wants moisture, it doesn't like to be submerged.
Different woods will defend against fungi, like bamboo, red wood, cedar ipa, teak etc etc. These woods are succeptable to- rot though, if kept wet for long periods of time just like any other wood.
Most boat manufactures just don't care about longevity, they care about sales and quotas and what material is cheap most times bought in bulk. This is also why you see poor conditions under decks in your boat when opened up, like drain lines that were never sealed off with epoxy to keep water intrusion out. Thats why you see alot of older boats rotten.
I believe the internet has caused manufacturers of today to be more diligent about there building practices, because people in general today are more informed about the poor practices that were done years ago. But some manufacturers will still built them cheap and sell new ones to those that really have no knowledge of the problem or just don't care because the cost of the boat is right and they want to go boating. The fact is, most people don't keep a boat for more than a few years, then its someone elses problem.
High end boats of todays era are expensive for many reasons, and the material they use is part of that equation, just like expensive or high quality homes will be more expensive than cheaper made ones, its economics, plain and simple.
Now back to the rot. Again, rot is caused by wood staying wet or atleast staying wet long enough that it becomes an attractive source of food for fungi. Fungi can not live without a water source. It will die without water. That being said, there are some that say that there are certain fungi that can create there own source of water/moisture, it has yet to be proven.
If you want to keep a boat from rotting, keep it dry! Saltwater or freshwater makes no difference. If water is allowed to soak into wood and stay wet, fungi will follow. Some fungi even feed off of salt!
Keeping a boat dry starts in the manufacturing stage. All wood has to be kept incapsulated as well as possible to not allow moisture to reach it. When boat manufactures have poor quality control and unprofessional laborers that don't seal every nook and cranny in the boat like drain holes ect, you are asking for rot to happen. I believe epoxy is better than polyester because its not as porous.
Everyone says that maintenance is key, This is true, but it is a simple fact that if you have an older boat that wasn't manufactured right, maintenance may prolong the inevitable, but exposed wood will eventually rott if water is allowed to continually get to it.
Other things to consider is, very few boats are made with any air flow. Remember, 20 percent and up moisture content will substain or attract fungi growth which rots/eats wood. Without air flow, a damp area is going to stay damp. Humidity is another thing to think about and different materials stay at different degrees which causes condensation. Without enough air flow, condensation alone can cause big problems.
The best solution I see is to use all composite materials for boat building in the future. And I mean trus composites, alot of composite, especially in the builing trades are a certain percentage of grinded up wood, trex for example. lots of law suits over that one.
To cap what I have said off, my 1990 boat I am sure probably has rot in it, air has water in it, boat has water around it and in it, not enough air flow below decks, had poorly sealed hatches, condinsation etc etc etc. I will use it until it is non-usable or the motor falls out.
Ohh, and I have seen just as many salt water boats rot as I have seen fresh water boats rot. Only difference is the self bailing decks save some from rotting as fast with less absorbing materials onboard to make them fancy like carpet. Offshore boats are in general made to higher specs mainly for sea conditions. But you can go to classic mako or any of the other well known brand classic sites and see that almost all of them have rot issues if they have wood in them.
Hope that helps.
