Listing of known Monsun weaknesses

Here is a short list of concerns about a technical issues on a Monsun. They were the most commonly discussed topics on the former Monun forum.

Monsun failure or weaknessDescription of the problem
Leaking portholes After many years of exposure to sun and salt the rubber strips around the portholes may leak and need to be replaced. You can find information on how to do this on the Monsun Forum.
gunk in the diesel tankThe diesel tank does not have a manhole to facilitate cleaning. Many tanks have a thick black tarry layer in the bottom of the tank, that has gathered over the years. It is difficult, but not impossible to clean this gunk out. You can read elsewhere how this can be done.
Engine replacement needed Many Monsun owners have already replaced their old original engines to new ones. In particular engines that have not been used a lot may need replacement due to corrosion inside the cylinders and cooling channels. The kind of replacements that are common can be found in the Monsun Forum.
Worn down lower rudder hinge Since the Monsuns are of age, it is worth checking whether or not the lower bronze hinge support of the rudder is worn down too much. When the boat is on land it is easy to check this. You can feel free play in the hinge if it is too worn. To replace this is quite a job, but very important in case it is worn.
leaking rudder stem In a number of Monsuns the sealing that sits around the rudder stem has collapsed and seawater is leaking into the stern stowage compartment.
deckstruckture leakage with old teak decks In many of the Monsuns that were fitted with teak decks the deck structure has leaked due to the many screw holes through the deck sandwich laminate. In some cases the boat has suffered from severe delamination in the deck. You can hear this by walking on a creaking deck.
Backing plate brokenThe backing plates in Selden masts where the T-endpieces go into the mast have been worn down too fast and may be broken.

Here are some known failures or weaknesses that Monsun owners have reported to our list

Many times owners have asked about possible flaws that they should check on their Monsun before setting out on the seas and oceans. This list may help in preparing for the worst.