The older the houseboat, the more likely it is to have a steel hull. Because of maintenance issues involved with steel, most newer houseboats have either aluminum or fiberglass hulls. However, the single most important advantage of having a steel houseboat hull is the protection it offers against impact. The strength of steel inhibits damage, and it is easily repaired. It is best to take your time and to research the pros and cons of each option.
Steel hulled houseboats require more maintenance than those with fiberglass or aluminum hulls. Annual inspections and maintenance are necessary when dealing with steel. This can prevent problems that interfere with use of the boat or can even cause it to be a total loss. A full pull-out inspection is not necessary every time, but this should be done at least every few years. Getting a dive inspection is sufficient in most cases, and it will also tell you if the boat needs to be dry-docked for repairs.
Topping the list of steel hull issues is rust. The two most common areas where rust starts are the bilge and the interior. If rust occurs, you will probably need to sandblast the area to remove the rust and reseal it with epoxy. Another option after removing the rust is to coat the steel with fiberglass. Dents can also be a problem, as they can make sailing less efficient. Fortunately, it is easy to pull dents out of steel hull boats without causing lasting weakness.
The total replacement of a steel hull is so expensive that most owners would consider the boat a complete loss. The value of the whole houseboat is often less than the expense of a hull replacement. Many owners of steel hull boats attempt a patch fix before considering a full replacement. This can work if it is done professionally. The only case in which a full replacement makes sense is if you are a boat welding professional who is capable and has the equipment to do it yourself.
It is becoming more and more difficult and expensive to insure steel hull houseboats. Some insurers will still do it, but they require extensive maintenance records and current inspections even to consider it. This is because rust problems can go undiagnosed and cause the boat to sink or otherwise be a total loss if it is damaged. If you do find a carrier who will insure your boat, make sure you read the policy carefully and have the insurer answer any questions you might have. You are more likely to get coverage if you carry other policies with the same company.