The original 9000 USD Catalina came with the original 6 HP Johnson engine... Well, it cost me about 100 USD and one day to fire it up with the help of a local mechanic. Then I made a trial run in a rubber dingy. That was real fun! The pump was apparently broken, so I had to pump manually every 15 – 20 seconds, otherwise the motor stalled. The dingy managed to get to the stellar speed of 3 knots, and once, when it was really ready to take off, even 4 knots for a brief second. Then, after about one hour and a half suddenly the gear shifted into neutral. I reengaged it, but after 5 minutes, the same happened. Then after 3, then after 1, and then, well, it never engaged anymore. I was in permanent neutral, on a small river in a small boat about 3 kilometers away from my car and had to row back (yes, at least it was with the current, I was not so dumb as to try out the engine going downstream…). At home I disassembled the gearbox, found many many small details which should not be in the state they were in and understood that the only way to go was to buy a new engine.

In my past, I was a purist sailor and considered those who run on engine as deficient people. I sailed J24s without engine and never felt the need for one. So at first I was hesitant whether it was necessary to buy a motor.

My outlook changed completely after an experience I had on a small lake here in Chile with my Catalina, on Lago Vichuquen. When I just purchased the sailboat, I was doing some testing on lakes, and on that particular occasion I was sailing around an 8 km. long lake. I did not have the motor (it was broken already). There was some wind, and I was doing fine, and I was at one end of the lake. At 19:00 I decided to sail up to the other end and sleep there... After 15 minutes the wind died almost completely. And then I started to make excruciatingly slow progress: 0.5 knots! I even tried to row with an oar, and was able to get up to 1 knot, but it was very heavy exercise.

At 11:00 I was half-way through the lake...

At 24:30 a motorboat approached me to see what I was doing. They said something like, wow, you are cool, man!

But I think what they meant was: we have never seen such a complete jerk!

Finally, at 1:30 I dropped anchor where I planned to stay for the night, cold, miserable, and very decided to buy a new engine. I was not a purist anymore!

I set my eyes on a two-stroke 5 HP Tohatsu. Initially I wanted a 4 stroke engine, but they were more expensive (two-stroke 5 HP Tohatsu costs 1500 USD versus 2000 USD for four-stroke 6 HP Tohatsu, and especially the alternator was like 400 USD extra for the four stroke version, compared to only 150 USD for the two-stroke version). Since I absolutely needed an alternator to charge the batteries, and although not a purist anymore, I did not know that I would motor so much. Therefore, I decided to go with the two-stroke version.

I also selected a propeller with very low pitch, 6 inches (standard ones go from 7 to 9), and never regretted that selection. I need low speed, but a lot of torque when going against waves.

So far, I have been running the engine for more than 400 hours and did not experience any problems. On absolutely windless and waveless fresh water it propels standard (before I did the keel modification) Catalina with 1 person onboard and little extra weight (70 kg) at 5.75 knots. Against waves of about 3 to 4 meters and 20 knot wind it can push it around 3 knots.

In the hindsight, I should have bought the 4 cycle version of the motor. To my shame, I have to admit that I almost always run on engine. I usually do not bother to use sails when there is light wind (less than 6-8 knots). I always hoist sails for medium wind (8 to 20 knots), and unless I am going straight against the wind, I still run on both the engine and sails to go faster. And only when the wind gets too strong (over 20 knots), I switch the engine off and go on just sails.

The big disadvantage of two cycle version is that it consumes about 30 % gas than the 4 cycle engine.

If you navigate a lot, it is a considerable amount of volume to carry around and extra expenses, plus, you have to buy the oil.

If I were buying an engine now, I definitively would go with the 4 cycle version.

There is only one downside to the 4 cycle engine: it is much heavier, around 28 kilograms versus 21 kilograms.

It may not sound important, but it is very difficult to carry a 28 kilogram engine. The 21 kilograms for me is about the maximum I can handle without breaking my back and arms.

And there is the issue of the engine mount which I believe for Catalina is limited to about 20 kilograms.

Higher power is absolutely useless. With 5 HP I am running at about hull speed, so that if I changed to let us say 10 HP, the gain in speed would be minimal. And as for going against the wind and waves, there is also not much to be gained with a bigger engine, because the limiting factor is not the power, but the stresses on hull and rig when motoring against the waves.

Running on Engine.