Les:

I think the Inter 18 used the same snuffer system that the I-20s are using. They are made of carbon fiber and not allowed in Formula 18 class racing.

Of course if someone is going to change out a mast then the snuffer should be no big deal.

Let's say that someone wants to upgrade an Inter-18 to Formula 18 and has the average one. They will be trading out a carbon mast for aluminum. Let's call that $900. They will need a new sail to fit the aluminum mast, I doubt that the same sail would work on the Carbon Mast and the Aluminum Mast competitively. That sail will run $1500. Then if you need to replace the snuffer you are in at least $300 for that. Now you are in an Inter-18 for $2700 not including what the boat is worth. Say the boat is worth $3000. You are up to $5700 for a boat that may or may not be competitive with the boats sailing today. If you are in this position you may consider getting a used formula 18 for about $8000.

If you were to buy a used Formula 18 for a good price you could sell it later and not lose too much money.

Just thinking before an upgrade may save some money and grief.

Later,
Dan