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Old 06-02-2011, 19:40   #1
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What's Your Heading ?

Please check my work. Iíve been reading here on the forum about Autopilots. You guys have shared excellent information for sure. I hope to discuss a couple of couple of technology concepts regarding autopilots since I have never owned one before. I hope to please center the conversation around:35 foot monohull Sailboats weighing approximately 18,000 lbs with Payload.

Hydraulic vs. Mechanical Drive:
I read some that hydraulic is mandatory when it comes to autopilots and others say that it is not. My boat has mechanical cable steering. Iíve also read that hydraulic is only preferred if hydraulic steering already exists. Hydraulic is also less energy efficient and consumes more power?

Over sizing the steering mechanism,
How much excess capacity do you need in a drive unit to increase reliability and longevity?

Rudder sensors, auto-learning computers with gyroscopes
I have a Catalina 350 that is 35.5 LOA and 13 foot beam. The stern is anything but canoe shaped. I liken it to more of a Snow Plow. Motoring to weather in a 25+ breeze is tiring. Motoring downwind in the same quartering sea is brutal. The wheel is a continuous fight. Do these technologies really work, or is it more marketing hype and great for a brochure? It would be worth it if a computer can sail the boat better in heavier weather.

Wind Vane Steering
How do you normally use your autopilot? For the most part, I like sailing my own boat. There have been long trips or heavy weather (like above) where I think an autopilot would be very useful. Letís say you are close hauled with a +/- 10 deg shifting stiff breeze. Can it really keep up?

Chartpilot/GPS navigation:
Unless I am missing something, this seems to me to be more of an afterthought. It seems like any GPS can steer an autopilot as long as it can communicate NMEA 0183 or 2000. I saw a demonstration of a Garmin that would avoid all obstacles, shoals, wrecks, etc on a course layout. Thatís cool.

Communication Protocol
There is NMEA 0183, 2000 and then manufacture specific protocols. This is a weak area for me since networking has not been a requirement. I can see this changing. I currently have the ST60 Depth, Wind and Speed cluster. I never use the speed indicator since if fouls too easy. I was considering the Raymarine ST70 with the X-10 Corepack. I was thinking I could replace the speed indicator with the ST 60, but the Raymarine site says it needs to be ST60+. So, I guess the ST70 will not fit??? Also, I got a sense that the Wind indicator will only work with SeatalkNG protocol. If that were true, then I would have to replace the Wind Instrument to get that feature. Does this sound right to you?

I donít think going with the Raymarine would be a bad decision. Itís just that if I cannot migrate my existing pieces forward, then I think it opens the field to other players like Simrad, etc. I also heard that Garmin has something cooking in the pipeline for Autopilot that is not yet announced. Although I'm a fan of oepn technologies, all this makes me wonder if latching on to a single vendor to take advantage of their specific technology is the right decision???
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Old 06-02-2011, 19:57   #2
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I'm on a 13 ton 41' sailboat with a benmar hydraulic pump married to a Nexus control head. Yes, I take a good amp draw to power my autohelm,- the old 1/4 hp drive pump, but it 's been working well for me for 26 years. 'not a system for using long term under sail.
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Old 06-02-2011, 20:20   #3
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IMHO:

* A Catalina 350 shouldn't be a big chore to drive. The recommended A/P for 18,000 pounds should be fine. Or the next larger.
* Nothing special about Raymarine.
* You don't need a GPS connection to the A/P.
* Sometimes an A/P can drive in adverse conditions, sometimes not. One either drives by hand or changes course.
* Mentioning windvanes here will cause a long discussion. For my boat and style a vane is not useful.
* Any A/P can take some fiddling with parameters to get it steering properly.
* Wind mode can sometimes work. I wouldn't rely on truly close-hauled sailing in any shifty conditions. I have considerable trouble on reaches as the apparent wind shifts far forward on puffs. Causing the A/P to bear away, and then back, and eventually into an accidental tack.
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Old 06-02-2011, 20:42   #4
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i found autohelm is crap in heavy weather. i have hydraqulic on the quadrant-- my quadrant is a cable drive. they work fine together--mine is simrad hyd2000. one cannot turn wheel with this when engaged,l not possible. tried it. can with autohelm. in heavy weather is not possible to use autohelm. we had to hand steer thru all heavy weather when i was sailing in gulf last yr. every other boat i sailed with autohelm was miserable in seas and winds. would not work. PO told me this works in seas. he loved it and used it everywhere even in tight places--i have yet to use it.
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Old 07-02-2011, 07:00   #5
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My 38' boat has a very light helm. I can usually steer with just one finger and and I suspect you can too. My mechanical drive autopilot steers easily. But I know of a 42' boat that takes much more force and needed a hydraulic autopilot. It's not just size, but the kind of rudder, its location and the efficiency of the steering.

I doubt you need hydraulic steering and you should avoid it if you can because it is much less energy efficient and you won't be sailing and steering on battery power as long without recharging.

An autopilot that can couple to a chart plotter is entertaining to watch, but not essential at all. I prefer just heading hold. It forces you have situational awareness and keeps you in the navigation loop. And because a lot of boats couple to chartplotters nowadays and follow a course within 100', you will find that you are frequently on conflicting paths with other boats doing the same thing. In the world of aviation, the practice of offsetting course right of centerline (like on a highway) has become official recommended practice in some situations because it reduces the probably of a mid-air collision.
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Old 10-02-2011, 18:14   #6
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Thanks so very much for your feedback. I had a chance to talk to the Simrad technical support and he recommended either the HLD350 (hydraulic) or the DD15 (Mechanical) steering mechanisms for my boat. He did not seem to indicate a preference for one or the other. He stated that the hydraulic versions have been since the 80’s and is a proven technology. The DD15 has an advantage for space considerations. He said they have had it for about 3 years with no reliability issues. I downloaded and read the manual on the DD15 and its pretty neat. It produces a enough torque for my boat with overhead to spare. It has an electro-mechanical clutch that completely disengages the planetary gearbox so there will be no resistance when off. It also will not break free until you manually overcome the holding pressure. This allows you to keep control of the boat when disengaging. We talked about the autopilots ability to steer the boat on heavy quartering seas. I think he gave me an honest answer in that any autopilot will struggle since there are too many boat specific parameters that have to be dealt with by the computer. He did state (unsolicited) that the autopilot would still do a better job than a person in this condition. That’s what I was hoping to hear. (Why shouldn’t it if the device can put hundreds of equivalent force on the rudder?) He did say that I would really need a rudder reference. The non-feedback computer controlled units are good for smaller sailboats or nimble powerboats. The Raymarine package that the website picked did not have a rudder reference. They seem to tout that they do not need it. Hmm. I haven’t talked to Raymarine because they want me to set up a user name and password. How many user names and passwords do we really need? I really do not want to do it. My take on this, I think that Simrad has more too offer from an engineered solutions standpoint. Not to knock their competition, but how can they quote hard over times when they do not know the moment of inertia of my boat? Very interesting . . . I'll leep you posted as I go along.
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Old 10-02-2011, 19:27   #7
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Quote:
Originally Posted by Windseeker View Post
I have a Catalina 350 that is 35.5 LOA and 13 foot beam. The stern is anything but canoe shaped. I liken it to more of a Snow Plow. Motoring to weather in a 25+ breeze is tiring. Motoring downwind in the same quartering sea is brutal. The wheel is a continuous fight. Do these technologies really work, or is it more marketing hype and great for a brochure? It would be worth it if a computer can sail the boat better in heavier weather.
You've asked a bunch of questions here; please forgive me for only focusing on the one quoted above.

I'm not IN ANY WAY anti-Catalina. The make some great yachts. But I've always felt that the cable steering systems they use make steering twice as hard as it needs to be. The systems also tend to be far more vulnerable than rack-and-pinon systems.

That said, given that you own a Catalina, it's probably better to invest in an autopilot one step up from the one you'd normally need on a boat that size. It's going to be working twice as hard, just as you are now working twice as hard as you should be.

Regarding the question of whether the technologies such as gyro systems really work, the answer is a resounding "yes!"
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Old 10-02-2011, 21:05   #8
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Ditto what Bash said. Go bigger if you can swing the power draw. I prefer hydraulic and have a Marol system and am getting a Comnav AP. I also use a KVH AC103 fluxgate compass. I do not intend to integrate the GPS because steering to a set course over, say, 10 NM and then seeing how close I get to where I think I should be tells me useful things about current and lee-making and things I can correct with sail trim and helm offset.

Because I also have a wind vane, I generally restrict the use of AP to motoring, so the draw isn't typically a problem. I have seen on passage the value of both, and how either (or both) can be disabled in heavy conditions.

How you sail and where and for how long will determine what you need, but most people I know avoid hand-steering like the plague once out of the harbour and a few miles off. So count on getting a lot of use on it, because under sail, switching on the AP and seeing how it reacts will give you plenty of sail tweaking work. It becomes a game to see how few times the AP corrects, because if it does almost nothing but correct for the swell, your boat is set up nicely and the power draw is less onerous.
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Old 11-02-2011, 08:43   #9
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Not my first choice

The Catalina wasn't on my initial list. I started looking at Sabre, C&C, Tartan and some other nice sailing boats. I would have bought a Tartan 3700 if I could afford it. With our lifestyle, we ended up in the Production Boat Category; namely, Hunter, Catalina, Bennetau - ones we could afford. The tradeoff with the Catalina is Creature Comforts. It's very roomy below. It really is a floating condo. We consider it to be a "working mans boat" - No exterior teak! It's accomodating for friends, weekends and week long trips. I consider it to be an ideal boat for the Chesapeake.

The more I think about how I might use the AP, the more I agree with you guys. Most likely, I will set a course on the AP, then adjust sails along the way. Cruising off a chartplotter and wind vane seems risky and best left to impress guests in a controlled environment.

This cable steering can be difficult at times. In heavy weather, the wheel is "jerky" and hard to control. I am constantly oversteering. The below deck AP drive would be connected directly to the rudder post which would isolate the steering linkage. So, I'm trying to decide if upgrading the steering to a Rack and Pinion would be worth it if the AP had the helm?

I can't imagine a Rack and Pinion conversion to be too expensive??? I can see alot of benefits to it. Taking the slop out of the cable system would be great. Would it be worth it? I'm sure this has been discussed on the forum somewhere.
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Old 11-02-2011, 10:38   #10
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In the Chesapeake, it's a different story (I've only spent a day there so please excuse my presumption, but I was looking around and peering at soundings all day long...)

I can't comment on the cost or benefit of the rack and pinion conversion, but I noticed the same thing steering a Catalina 470 on a race last summer...it's like there's a sort of series of marbles on the groove of the quadrant, or one of the little sheaves was slightly elliptical...

Anyway, it won't get better and might get very annoying year after year. So irrespective of what AP solution you decide, I would be focused on remedying or swapping out the existing wobble in the helm.

God, that would drive me nuts.
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Old 11-02-2011, 10:51   #11
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[QUOTE=Windseeker;616718]
This cable steering can be difficult at times. In heavy weather, the wheel is "jerky" and hard to control. I am constantly oversteering. The below deck AP drive would be connected directly to the rudder post which would isolate the steering linkage. So, I'm trying to decide if upgrading the steering to a Rack and Pinion would be worth it if the AP had the helm?

If you're cruising and not racing you may find the AP sufficient, granted that you have one that attaches to a rudder quadrant. Most cruisers run on AP most of the time. Yours will have to work a little harder than most to deal with the cable slop.

It's a different story if you race, where use of an AP will lead to a DSQ. A few years back I crewed on a Catalina 42 in the Double-handed Farralons race on a blustery day. On the downwind leg, we had to relieve each other at the helm every 30 minutes because the steering system would exhaust us. (Not that running a spinnaker downwind in steep seas in 35 knots true wouldn't tire anyone on any boat that size, but on the Catalina it was especially punishing.)

Great boats, however, once you get past the cable steering.
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Old 11-02-2011, 16:59   #12
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Awesome. I think that settles it. Since it is 100% pleasure cruising, I'll get the AP, connected to a tiller arm on the rudder post. If I find that I have to disengage the AP and find the steering too difficult, I'll upgrade the steering machanism then. I'm really glad we talked this through. It's less confusing and I can see my way to the end result. Great to bounce this off someone. Thanks! Marbles! LOL! I know what you mean.

Bash, the only thing that I can't wrap my head around is how the AP would work harder if its attached to the rudder post. I could see a wheel pilot having the same struggle as me, but wouldn't I bypass the entire steering mechanism by attaching to the rudder? There is something I am missing. What am I missing?
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Old 11-02-2011, 17:15   #13
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G'Day all,

Just a comment: The blanket condemnation of cable steering is misleading. It is certainly possible to have a cable steering setup that is smooth, low friction and has little free play. I don't know what it is about the Catalina system that is causing these folks such grief, but surely some attention to better turning blocks and their mountings, perhaps better wire in the cables, careful alignment and so on would be far more cost effective than replacement.

And for Windseeker: A direct drive to the rudder post may remove the problem, but you are still driving the whole steering system. Thus, if there is a lot of friction currently, it will still likely be there with direct drive, and so on.

I guess that one source of the difficulty could be that the whole system distorts when the cables take up big loads. If this is the case, then the direct drive will indeed help out.

Good luck with the solution.

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Old 11-02-2011, 17:34   #14
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Mr. Cate: I don't think there is any condemnation of cable steering/quadrants. It is by far the most common boat choice of steering gear between 30 and 50 feet, I would gather. Even pro-tiller guys like me prefer it to tillers upward from 35 feet where the forces get a bit much for tiller.

I do sense, however, a condemnation of how Catalina rigs their cables and, likely, their alignment. There's little excuse for a company as large as this to have clunky steering "feel" and maybe the desire to jam a big aft cabin in 35 footer is making the angles a little too tight for the steering works. Just a guess.

Mr. Windseeker might want to figure out a really solid mount for his tiller pilot, plus a way to cover it from the elements and spills. I use an ancient Autohelm 1000, granddad of the current Simrad tillerpilot, on my 33 footer, and it works very well when I need to motor/motorsail any distance and prefer not to grow skin cancer at the helm.
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Old 11-02-2011, 19:10   #15
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[QUOTE=Jim Cate;617135]G'Day all,

"I guess that one source of the difficulty could be that the whole system distorts when the cables take up big loads."

This very well could be the case as the system is managable and fun in 10-15 and gusts to 20 knots. When it starts blowing 25+ the FUN stops. As much as I like to sail, I don't even go out in 20+ I like this distortion theory because so many other boats just put up their sails and go on by in heavy weather.

This forum is great because it has inspired me to download the Edson installation and maintenance manual. I never knew it needed lubrication!
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