Join Date: Apr 2007
Location: St Thomas USVI
Thanked 38 Times in 36 Posts
Rep Power: 13
Re: Monohull to cat
I frequently go out for a day to get people comfortable with the transition from a mono to a cat. Yes you can drive them like a tracked vehicle at low speeds. As soon as you're doing about 2kts the rudder will start to have a reasonable influence, use it. A common mistake I see beginners make is to try and get the boat to steer with throttles, not the wheel, at 4-6kts. Use the rudders and save the transmissions!
Tacking in lighter wind takes a little finesse. Many mono guys want to throw the helm hard over which completely stops the forward speed and generally stalls the boat in irons. Which way the boat will fall off is anyone's guess at that point. Start a tack and think more like your are "carving" a turn like on skis or ice skates. Just like with skates or skis, an aggressive turn is how you stop. Is that what your are trying to do? Probably not. Get the boat momentum going the way you want and then steadily turn more to get the bows to come across. Do NOT let the working sheet go early, which is another bad mono sloppy sailor habit. Many charter cats need the power from the headsail all the way through the tack. Some cats even need to be backwinded to get around or start the appropriate engine to push the leeward side around. Get the boat all the way through the tack and turn to maybe 60 degrees AWA to build some speed back up while trimming. Trim and head up if you are beating to the desired course.
Reef based on the windspeed shown on your gauge and listed in manual or instructions. Do NOT carry more sail than the manual or charter company instructs you to. Some cats are actually faster when reefed "on time" because when overpowered they are burying the leeward hull and dragging it which causes more helm input to go the desired course. Reef, watch the boat get flat and fast.
Rarely does it help to have 6 people standing on the trampoline all giving instructions to the skipper. Because there is room up there, everybody thinks they need to be in the middle of the action. What they do is make an impressive wall so that the helmsperson can't see anything.
Some cats have a helm that provides better visibility to one side. If so, make that the side you put on a dock or pick up moorings from. Many times no direction needs to be given if most of the people stay in the cockpit and out of the way until tied up.
Be very aware if towing a dinghy. Putting an engine in reverse to maneuver will inevitably suck that painter right into the prop. Personally I've never understood why dinghies are towed behind cats. Most cats have very robust davits and it only takes a minute to raise and secure the tender. Actually, be aware of any line going over. Cats love to suck in lines and wrap them up. Unless you've got some serious time on a cat, you really can't understand how challenging it is to drive a cat with just one engine at low speeds in a crowded area. It seems like prop wraps always happen in crowded areas too!!!
People seem fascinated with swimming/snorkeling under cats. I've had too many occasions when I've done my prestart lap around the boat and found some knuckle head under the bridge deck looking at a barracuda. LOOK before you start up.
Above is the free version of what I go over with most people. I usually cover MOB, anchoring and a few other things that are far easier to demonstrate rather than try to describe.
Enjoy your trip.