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Autopilot fitting - Mad idea or been done before?

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George Isted View Drop Down
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Post Options Post Options   Quote George Isted Quote  Post ReplyReply Direct Link To This Post Topic: Autopilot fitting - Mad idea or been done before?
    Posted: 22 Oct 2013 at 4:52pm

The normal position for an autopilot in a Co32 is to fit it to the top of the starboard seat bench, and while this works ok it does lead to a couple of problems..

1.The fixing point on the tiller is outside the 14-18” range of how far it should be fitted from the rudder stock, this leads to….

       a. not being able to put the helm fully over for a big course correction (often needed when under spinnaker) or to Tack

       b. secondly it makes the autopilot work harder as it has to extend or retract the ram more for a given course correction

2. the tiller pilot is vulnerable to being sat, knelt or stood-on.

 

3. In the case of the larger fixed-installation Autopilots (I’m thinking Raymarine ST4000, SPX-5 and the latest one EV-100) the Ram is a little too long to be fitted at right-angles to the tiller so you either fit it slightly a-skew or accept that it will push the helm further over to port than it will too starboard.

 

Having used my ST2000 close to self-destruction (they are really not rated for extended use on a CO32) I want to fit Raymarine’s latest offering the EV-100, but I also don’t want the restrictions above.

 

A bit of measuring-up suggests that the best place to locate the Ram would be just under the cockpit seat with the ram recessed into the cockpit side using a suitably strong custom-made GRP moulding that can be bonded from the inside to the cockpit side, with additional bonding to the underside of the seat to ensure it takes all the loading with no problems.  The downside is that I would lose perhaps 4-6” of height at the very end of the quarter-berth.

 

So, tell me, is this a mad idea?  Anyone foresee a problem with this?

George Isted
Contessa 32 "Concerto"
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moongirl View Drop Down
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Post Options Post Options   Quote moongirl Quote  Post ReplyReply Direct Link To This Post Posted: 23 Oct 2013 at 8:31pm
George
One thought occurs to in particular, namely the push/pull load would increase the closer the ram attachment to the rudder stock ie less leverage - you wouldn't try steering with your hands way down the tiller!
I will have a look at the EV 10 to see the relative diameters of ram/housing - would you push the assembly through the cockpit side into the quarter berth?
Some ingenuity might be needed at the inboard end as gravity normally holds the 'pin' into the seat and with your suggestion a bracket would be needed to replicate this as the deck head would be above.
Hope this helps
Regards
COLIN
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Post Options Post Options   Quote moongirl Quote  Post ReplyReply Direct Link To This Post Posted: 23 Oct 2013 at 8:49pm
Hi George
Had a look at the Unit and it appears conventional ie large tube with a smaller ram and 'pin' type fixings either end. So my previous post is correct!
Over to you for the Geometry! 
Regards
COLIN
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Post Options Post Options   Quote George Isted Quote  Post ReplyReply Direct Link To This Post Posted: 24 Oct 2013 at 10:37am

Hi Colin,

You are correct on both counts, yet the loadings will be higher but my intention is to stay within the manufacturers range of 14-18” from the stock so should be ok.   At the moment it is not possible to fit the tiller within this range without either lifting up the tiller or lowering the Ram.   My st2000 is approx 20” from the stock.

 

An alternative solution to have a tiller-pin in the 14-18” range with sufficient height to allow a seat-top installation would be to have a much larger and taller fitting on the tiller but it would not allow the tiller to lift up and out of the way when not in use (rough measurements suggest a taller tiller fitting would hit stern cockpit locker-top before the tiller was fully lifted).

 

The Ram is unchanged from earlier models, it is just the controller (Brains) and movement sensor/compass (Nervous system) that is new on the EV-100.  The Ram is the same as was on the SPX5, S1 and  ST4000.

 

The plan is to still use gravity to keep the Ram located into a custom GRP moulding in the side of the cockpit (extending under the seat and into the top of the Qtr-berth).

George Isted
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Post Options Post Options   Quote nardus Quote  Post ReplyReply Direct Link To This Post Posted: 28 Oct 2013 at 8:56am

The EV 100 takes 11 seconds to make a full correction from port to sb.. Will this be sufficient when the chute`s up in moderate winds? Why not hooking up your st2000 on your Windvane Steering ?(if you have one) faster response, less draining on the batteries, more steering power and no mounting problems.

Ben H
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Post Options Post Options   Quote George Isted Quote  Post ReplyReply Direct Link To This Post Posted: 28 Oct 2013 at 12:13pm

Hi Ben,

Where did you get the "11-seconds" from as I cannot find that in the specification and it seems a long time.   Raymarine used to give this info for the ST1000 and 2000 models and I recall the 2000 being much faster.   I can not find this info at all now for any model.

 

The windvane steering is very good on a longer offshore trip but not ideal for inshore/coastal sailing/racing + the cockpit control lines get in the way if you are having to be active in and around the cockpit playing with spinnakers.  Also the windvane (and st2000) struggle when reaching with the spinnaker in marginal conditions, it is one of the reasons for buying a decent fixed-install pilot.

George Isted
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Post Options Post Options   Quote nardus Quote  Post ReplyReply Direct Link To This Post Posted: 28 Oct 2013 at 4:18pm
found it here : <KLICK>
Ben H
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Post Options Post Options   Quote George Isted Quote  Post ReplyReply Direct Link To This Post Posted: 28 Oct 2013 at 4:24pm
Ah, I think that is for fitting to a steering quadrant on a larger boat.   The standard tiller ram that comes with the EV100 is http://www.raymarine.com/view/?id=7679&collectionid=65&col=6603
George Isted
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Post Options Post Options   Quote nardus Quote  Post ReplyReply Direct Link To This Post Posted: 29 Oct 2013 at 9:46am
My bad, but I can`t find the lock to lock time specs for this tiller ram anywhere ?
Ben H
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Post Options Post Options   Quote George Isted Quote  Post ReplyReply Direct Link To This Post Posted: 29 Oct 2013 at 10:01am
I shall ask Raymarine tech support as that's good info to have.
George Isted
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