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-   -   Let's talk self-steering systems... (http://www.sailnet.com/forums/gear-maintenance/59108-lets-talk-self-steering-systems.html)

byr0n 10-20-2009 07:43 PM

Let's talk self-steering systems...
 
I am having a hard time finding good information on self-steering systems other than patents and DIY stuff (or blog posts like "mary monitor steered us 'round the world").

It seems to me that a self-steering system would and could work on day sailors and the like, but am not clearly understanding the reasons for not having them. I know the obvious reasons like unsettled wind and active handling of the boats in coastal and short trips making a vane unnecessary, but really, given the choice between burning down my tiller-pilot piston, or hanging up a t-shirt tied to the tiller fr an hour or two, seems to me that a throw-away model of an above water system for self-steering wouldn't be all bad. In thinking about it, I thought I might just drum up a bit of conversation here, as you all know more than me.

This is a 2 part question. First, when/if you were/are looking for a self-steering option why did you consider one of the particular designs over another. Servo-pendulum, horizontal axis, direct (either above water or tiller integrated) or trim-tab? Was is referenced boat designs accommodating different systems? or transom design, mounting, or weight? maybe moving parts, or lack thereof? overall size?

Second, would you consider it useful to have a smaller, cheaper option for coastal cruising?

I am thinking of a "t-shirt tied to tiller" type throwaway-able self-steering with an adjustable correction (sensitivity) that can be hooked up for an afternoon trip on a 20-35 footer with minimal impact and installation requirements. I am thinking of this sort of tool, but am really looking for knowledge as to whether this would be useful to the day sailor.

so, yeah. Thoughts? (and yes I know that was actually like an 8 or 9 part question)

JohnRPollard 10-20-2009 08:24 PM

Quote:

Originally Posted by byr0n (Post 534087)
...I am thinking of a "t-shirt tied to tiller" type throwaway-able self-steering with an adjustable correction (sensitivity) that can be hooked up for an afternoon trip on a 20-35 footer with minimal impact and installation requirements. I am thinking of this sort of tool, but am really looking for knowledge as to whether this would be useful to the day sailor.


One of the reasons (among others) they tend not to be popular for coastal/daysailing, is that they are of necessity built quite robust in order to withstand the hydrodynamic forces that give them their power. This then requires an equally robust mounting arrangement, often including a beefed up transom or very substantial backing plates to withstand the loads.

It's difficult for me to grasp a lightweight self-steering system such as you describe. A "t-shirt tied to a tiller" ?? How would a t-shirt provide the substantial power necessary to steer a boat?

byr0n 10-20-2009 08:40 PM

Quote:

Originally Posted by JohnRPollard (Post 534102)
It's difficult for me to grasp a lightweight self-steering system such as you describe. A "t-shirt tied to a tiller" ?? How would a t-shirt provide the substantial power necessary to steer a boat?

Just using that as a visual queue. "She'll track if'n I tie a t-shirt to the mast!" the point is to ponder something simple, with parts simple and available to fix (as all things will disintegrate).

Really , a system similar to the older, fabric vanes vs. the new ply/composite/metal vanes for the wind drive, and a simple above-water direct-to-tiller style control to eliminate the need for re-enforced mounting that the hydros etc need. if you remove the balance/counterbalance of the in-water systems, you are left with the task of balancing a "mini-sail" to control the heml via block+tackle.

The forces driving a vane at 30+ knots are the same forces that keep 99% of boats in this size range off the water all together so in thinking about it, I was thinking a light weather/moderate weather system.

As for power, we are talking math here. force versus area of the vane, coupled with gearing (think about the 30:1, 50:1, 100:1 ratios that worm gears and the like provide) suitable to move a tiller or helm with 20-40lbs of resistance. Pulleys and gears combined can do this sort of thing...

a 6:1 purchase will allow one to hoist oneself up a mast. a 60:1 will allow a 20" vane to move a wheel with 50lbs of resistance. The tiller being the most direct to the water, does require a fair amount of pull in a good blow, however a worm gear has an advantage of a sort of "no slip" inherited via its design which could really help in such design.

St Anna 10-20-2009 09:01 PM

Ok, how simple do you want?
If the boat is balanced on certain points of sail, then a rubber from an inner tube may suffice on the tiller. In the old days, downwind, twin headsails sheets (or 3rd sheet) on the tiller.
Good luck. Oh -BTW I have Fleming for sale....

GaryHLucas 10-20-2009 09:07 PM

Through the wonders of modern electronics, plastic injection molding, cheap labor in China etc, it is a hell of a lot simpler to just buy a tillerpilot. I paid about $500 for simrad 2000 for my 26 footer, and didn't have to make a ton of modifications to install it. So how well does it work?

We were running up the Chesapeake bay wing and wing with the tillerpilot steering and the wind speed kept climbing. When the boat speed passed 7.4 knots steady I wondered about how hard it was to steer. So I turned off the tillerpilot and hand steered for a while. HOLY ****! It was all I could do to keep from tripping over the bow and slamming her over on her side! The rudder had that loosey goosey feeling you get just before bad **** happens. I put the tillerpilot back in control, then shortened sail!

A very enjoyable toy.

Gary H. Lucas

byr0n 10-20-2009 09:17 PM

Quote:

Originally Posted by St Anna (Post 534117)
Ok, how simple do you want?
If the boat is balanced on certain points of sail, then a rubber from an inner tube may suffice on the tiller. In the old days, downwind, twin headsails sheets (or 3rd sheet) on the tiller.
Good luck. Oh -BTW I have Fleming for sale....

If this were the case, then there would be no need for a self-steering system across the board, big or small boat, offshore/inshore. The point is that self-steering traditionally is there to accompany the >26 ot <60 offshore.

However, its function could be useful for a wider range of size vessel and in a wider range of location. (specifically inshore) there are a LOT of 20-30 foot vessels around me, hence the thought, and questions. I am speaking of above-the-water systems (ie, paddle/vane to steering systems).

I am not aware of too many <30 vessels which are self steering via sails alone. The lack of effective keel/draft leave this whole range of boats out of luck with steering systems. More precisely, I am not aware of that many skippers. We aren't all gods of the wind and sea. :(

A rubber band will only keep a perfect sailplan on limited points of sail, and it will drive you in a straight line even when the wind changes direction past the radius of the rubber band destroying the system , whereas a vane driven steering system will continue to accommodate a large change in direction, more important too when discussing smaller boats in generally protected waters where wind shift is actually a much greater concern (remember, a self-steering system is designed to keep you on the wind, not on the compass...).

I suppose the discussion comes down to more of an ""effective turning radius". I am sure there is a name for that.

byr0n 10-20-2009 09:26 PM

Quote:

Originally Posted by GaryHLucas (Post 534119)
Through the wonders of modern electronics, plastic injection molding, cheap labor in China etc, it is a hell of a lot simpler to just buy a tillerpilot.

Yes, yes I am aware of such new-fangled contraptions. I do own an ST2000+ for my cal. That was not the point of the discussion.

The point of the discussion is whether it is reasonable to utilize something which isn't NOT modern electronics yet, can effectively keep you on the wind for less than sending 500 dollars of my hard earned money to China...

St Anna 10-20-2009 09:29 PM

Quote:

Originally Posted by byr0n (Post 534122)
If this were the case, then there would be no need for a self-steering system across the board, big or small boat, offshore/inshore. The point is that self-steering traditionally is there to accompany the >26 ot <60 offshore.

Yes but for a short period of time - it does work.

mitiempo 10-20-2009 11:24 PM

If everybody out for a daysail was using a wind vane I think it might be the time to buy a motorhome - the roads are crowded but at least most:eek: are watching where they're going.
There used to be a windvane built in England called the QME I believe (for Quantock Marine Enterprises). I can't find a picture on the web. It was a horizontal pivoting vane with a counterweight and lines to the tiller. The base was on a bearing and when sails were set you weathercocked the vane and cleated off the tiller lines. It was quite inexpensive at the time. Problem was if your boat wasn't balanced well enough it didn't work that well as it wasn't that powerful. There is also the "Mister Vee" vane produced in England currently. Those Brits like to tinker.
www.mistervee.com - Home
I believe plans are available from that link.
Most of the self steering systems that survived have developed into powerful reasonably maintenance free systems that work very well. The one I'm looking at is the Norvane, made in the US and quite affordable compared to the more popular names like Monitor. NORVANE Self-Steering Wind Vane. Stainless steel, servo-pendulum. Powerful, sturdy and reliable for sailboats 20’ to 60’
There is also a Windvane Forum that might be useful.
Cruising Sailor &bull; View forum - Windvane Forum
Hope this helps
Brian

mitiempo 10-20-2009 11:39 PM

Here's another website that may help.
http://www.mindspring.com/~waltmur/Self-Steering/
Plans are available from this site.
Brian


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