A sailing cat without a mast - Blesphemy?

[Captain Bill]

I have an Endeavour 44 sailing cat with 2 Yanmar 40 HP sail drives. The power cat version has two 240 HP Yanmar shaft drives. One thing to remember is that sail drives are designed as auxiliary propulsion and will not last as long as shaft drives if used exclusively for propulsion. My sail cat has 110 gallons of diesel and will cruise at 6 knots on about 3/4 of a gallon per hour on 1 engine or 7 knots and 1.5 GPH on two, or about 8.75 knots at full throttle. The power version will do 16 knots at full throttle or cruise at 8 knots at 3 GPH on two engines. I don't know what it burns on 1 engine, but since it does not have feathering/folding props it might not save a lot of fuel dragging the fixed prop. My feathering props cause me to loose about 1/2 knot if not feathered. The power cat hold 500 gallons of diesel so has a slightly longer theoretical range at a slightly higher speed. I think that The durability of the direct drive is something to consider if you are not going to sail. If one reads the service manual of sail drives you will see that the service life of the needle bearings is only 1500 hours. While many go longer than that, that basically tells you they are not designed as primary propulsion devices. I think that is why so many full time cruisers, myself included have so much trouble with sail drives. I think they are designed to get you in and out of the harbor, not to motor you 1000 miles.

While cats are pretty stable most have an issue in a beam sea at certain wave lengths, mostly when one hull is on a crest and one on a trough. When the sails are up the sails buffer the motion, but with no sails the motion can get quite uncomfortable. Without sails up the mast acts as a big pendulum which makes it worse and raises the CG. I think this might not be so bad with the mast off. The power version places large heavy engines and fuel tanks very low in the hulls which lowers the CG and reduces the motion problems in a beam sea. Each brand of cat has a different critical beam sea wave length depending on the beam.

I thought these items might be a couple that had not been previously mentioned that you might want to consider.

[Goosebumps]

I own a Catalac10m so a 34 footer with loa of 28 feet. A powercat owner admired the hulls on it and claimed ideal to transform my Catala to powercat. He suggested to put two 4cyl diesel marine engines in it. My question to ghose more knowledgable, how fast can it go without planing with those 4cyl 50 hp? Would the sD20 saildrives be able to cope with the increased power?

[dpddj]

When we chartered a sailing cat in the Abacos, the charter operator said many people never put the sails up and just putter around. A friend of mine says he charters sailing cats, never uses the sails, because they are cheaper to charter than power cats and does what he wants it to do - provide space and comfort.

It's a boat, after all, and that's the most important thing. You may find out that you really are a sailor.

[valhalla360]

To the original question: Assuming you can find a sail cat in good condition at a good price, it's a great idea.

Yes, you will lose the high top end speed of a dedicated power cat but otherwise you win with just about everything else.

Our plan (at least before the euro fell and we are looking at possibly buying over there instead) was to pull the mast off our Gemini. We would put the mast in my brother-in-laws pole barn and ship the Gemini to Europe for a few years. No worries with bridge clearance and she is about perfect for the canal systems. We've had the mast down for longer distances on past trips (erie canal - 300miles and central river systems - 1300miles) and she motors fine. We have around a 350mile range under power (with a couple of supplemental 5gal jugs) as long as we don't push too hard, so no worries there.

About the only modification we would need is a stub mast to support the anchor light and vhf antenna.

I don't buy the sail drives wear out to quick (not that they don't need maintenance). As someone else mentioned, if you find your way down to the ICW, you will find better than 90% of the sailboats that go by do so under power not sail.

I would strongly suggest keeping the mast in storage as you will take a major hit on resale if the mast is missing.

[Scout 30]

Originally Posted by valhalla360

To the original question: Assuming you can find a sail cat in good condition at a good price, it's a great idea.

Yes, you will lose the high top end speed of a dedicated power cat but otherwise you win with just about everything else.

Our plan (at least before the euro fell and we are looking at possibly buying over there instead) was to pull the mast off our Gemini. We would put the mast in my brother-in-laws pole barn and ship the Gemini to Europe for a few years. No worries with bridge clearance and she is about perfect for the canal systems. We've had the mast down for longer distances on past trips (erie canal - 300miles and central river systems - 1300miles) and she motors fine. We have around a 350mile range under power (with a couple of supplemental 5gal jugs) as long as we don't push too hard, so no worries there.

About the only modification we would need is a stub mast to support the anchor light and vhf antenna.

I don't buy the sail drives wear out to quick (not that they don't need maintenance). As someone else mentioned, if you find your way down to the ICW, you will find better than 90% of the sailboats that go by do so under power not sail.

I would strongly suggest keeping the mast in storage as you will take a major hit on resale if the mast is missing.

The best post yet. People have been turning monohull sailboats into trawlers for years because they can be a lot cheaper to buy. It was only a matter of time before people started doing it with cats.

[Cadence]

Originally Posted by Scout 30

A cat crewed charter would be interesting indeed. Just don't bring your dog along!

So, I dropped the comma. You're quick on the uptake.

[Cheechako]

Another thing to think about... aren't the rudders smaller on a power cat? I guess maybe they wouldn't have to be though....

[valhalla360]

Originally Posted by Scout 30

The best post yet. People have been turning monohull sailboats into trawlers for years because they can be a lot cheaper to buy. It was only a matter of time before people started doing it with cats.

I know of a few older genimi's that have done this.

Actually a cat is a far better option than a mono for conversion. Initial stability is the issue. The cat has tremendous initial stability from it's hull form. The mono relies on the mast's roll motion of inertia to develop initial stability. Take away the mast and it's like a weeble wobble. It won't fall down but it will wobble all over the place.

The reason I don't think you see more is simple numbers. There are still drastically more old mono's lying around than cats. Likewise, there are very few older power cats to be had on the cheap compared to sail cats. In 10-20yrs it may be different.

[Cadence]

I made friends with a couple that had a 36' Endeavour Cat Trawler. It was impressive.
It seems Endeavour no longer makes it. They added 2' and doubled the HP. The 36 had twin 125s I believe and V drives. Worth a look if you can find one used. I have no cat in the fight so you can bring your dogs.

[valhalla360]

Originally Posted by Cheechako

Another thing to think about... aren't the rudders smaller on a power cat? I guess maybe they wouldn't have to be though....

Yes but if you are traveling at the same speeds (ie: sailboat/trawler speeds), the slightly larger size isn't a major drawback.

[Scout 30]

Originally Posted by Cadence

So, I dropped the comma. You're quick on the uptake.

Just a feeble attempt at humor.

[Cadence]

Originally Posted by Scout 30

Just a feeble attempt at humor.

I thought it was humorous.

[Scout 30]

I know a guy in Tarpon Springs with a professional marine business. He built a huge sailing cat that he planned to charter in the Caribbean. His plans changed before he got the sails made which was going to be a major expense. He decided to sell the rig & turn it into a power cat. At the time Passage Maker had an article by cat designer from Australia or New Zealand who was adding a flat planing surface aft of the rudders so I gave this guy the mag. Not sure if he ever added them but he did swap out the motors with bigger Yanmars.

[k9medic]

Originally Posted by Scout 30

I know a guy in Tarpon Springs with a professional marine business. He built a huge sailing cat that he planned to charter in the Caribbean. His plans changed before he got the sails made which was going to be a major expense. He decided to sell the rig & turn it into a power cat. At the time Passage Maker had an article by cat designer from Australia or New Zealand who was adding a flat planing surface aft of the rudders so I gave this guy the mag. Not sure if he ever added them but he did swap out the motors with bigger Yanmars.

I think I know this boat. I have seen it several times on visits there and if it's the same one, seeing this boat is what got me thinking about making a conversion. I recently had a bottom job done at Pitman's Marine and the boat was next door.

[Scout 30]

I think the difference between cats designed for sailing & those designed for motoring is dealing with center of effort. Power cats are pushed from the stern & will have more of a tendency to squat. The center of effort on sailboats is farther forward plus the leverage from the mast tends to pull the stern upward. Because cats are not true displacement hulls they can exceed hull speed but under power they will still tend to squat which would limit speed if not compensated for. Therefore, while it may be tempting to throw more horsepower at them, without modifying the hull there may not be much point.


I do think that there would be a benefit to removing the mast if you don't plan to sail & don't plan to increase horse power because the amount of windage created by the rig can be significant which could affect speed when heading into a strong headwind.