Jump to content

Instruments and Autopilots - current systems


Recommended Posts

That is good TimB, another source to stow away in my files. There are several suppliers of Stainless rams. I don't like the idea of the electrical parts (pump, solenoid etc) being exposed to the weather, so I'd be firmly in the Electronics below deck category...

Link to post
Share on other sites

I have the electrics down below in the dust and the ram upstairs driving the tiller.

241_4200_1.jpg

 

 

Proprietry system in my case , but I agree there's a gap in market.

Boy do people start talking gobbledegook as soon as you mention its a tiller steered boat!

 

and while we're at it, what does size of boat have to do with anything? Its the force required on the tiller that is of importance ,shirley.

Link to post
Share on other sites

I'd have a tiller pilot over anything hydraulic any and every day all day long.

Its got to be at least 150 kilos lighter than what your suggesting.

Link to post
Share on other sites

Wind vane for passages, with a tiller pilot connection for when motoring or no winds. There is almost no load on the tiller pilot used in this way and you can use one of the lower powered versions  for that very reason.. plus a lot cheaper than a heavy duty ont directly connected to the tiller. The only proviso is to have the TP unit either out of the weather  as you can if connected to a capehorn self steering system or with a custom cover to prevent water getting where it shouldn't when connected to an aries etc.

Link to post
Share on other sites

 Maybe I take a whole bunch of spare tiller pilots....or are they really that fragile?

I've had one TP for 15 odd years and it's been raced rallied and rolled as well as used to beat a large angry Kahawai to death and open beer bottles. It was second hand when I got it. I have another that's 6 odd years old and done a mother load of work including one long passage when the winds top 55kts for a couple of hours. Both still work exactly as they did the day they came out of the box. Both only get grizzled at when flat running or when motoring.

 

I was 400nm south of Tonga heading home when a 2 year old fully built in commercial Coursemaster AP totally failed. I was mid Tasman when a well known brand name recreational one that was also built in totally failed.

 

Coursemaster is a long standing good name manufacturer of AP's commonly found on commercial vessels.

 

That tells me 2 things -

1 - Anything lectronic can fail no matter how flash they are supposed to be.

2 - You can't throw a blanket over item type X and say it's a lemon and Y isn't.

 

By far the biggest input into any longevity and performance would be the boat they are on and how they are installed.

Link to post
Share on other sites

I'd have a tiller pilot over anything hydraulic any and every day all day long.

Its got to be at least 150 kilos lighter than what your suggesting.

A full Simrad system weighs about 20kg incl ram and pump.

Cant see how your tiller pilot weighs -130kg. And tiller pilots do not deal with difficult conditions very well in my experience. 

Link to post
Share on other sites

A full Simrad system weighs about 20kg incl ram and pump.

Cant see how your tiller pilot weighs -130kg. And tiller pilots do not deal with difficult conditions very well in my experience. 

Unless your AP runs on salt spray and magic you may have forgotten the weight your power generation installation.

 

I have 24.3kg in total with a full fuel load and can put out 8amps on a good day.

Link to post
Share on other sites

Power generation is there anyway - towed gen weighs several KG, alternator weight several KG, solar panels weigh next to nothing, batteries would be there still AP or not - going from wind vane to AP we did not have to upgrade anything at all in the generation or storage systems. The towed gen is very useful in that if the AP is working harder it tends to be working harder...

Link to post
Share on other sites

I'm in the camp of the electric tiller pilot sceptics.

I had three of two different brands over 3 years with a previous boat. Yes, that is a few years ago now. All three did not last a year of regular Cook Strait crossings. Maybe they have improved, but I've yet to see the evidence.

These are normally worm drive systems, often with many plastic components, even the tiller connection. I've seen quite a few of those connections fail over the years. I do know of one cruiser with a 30ftr that uses one, and has had a ss end made for it for the tiller connection. Mostly, the manufacturers don't say they are suitable for crossing oceans!

Personally I think on a small boat without room for solar and or wind gen, a wind vane remains the best option.

For weight, 150kg is way too much - if you just want an AP power unit. The best way is to generate as required - wind gen and solar works best. If weight conscious, then the new lithium based fast charge batts make a lot of sense, as does a large frame hot rated high output alternator. Some lithium bats can be charged at their rated capacity, and fully discharged iirc. That means a 200amp hour batt can be fully charged with a 200 amp alt in an hours engine running. That would give about a day running an AP at an average 8 amps - a pretty high average. Lots of options to think about, so as an individual can select the system that best suits their particular requirements.

Link to post
Share on other sites

The thread is trying to apply cruising in big heavies thinking to racing in lightweights. The 2 are considerably different.

 

Hanging up a 2 sqmt sail on most of your boats would make no difference, on mine I have a 4-5sq/mt sails that has pushed me a long at nearly 4kts. That sail is called the 'Undies changer' i.e. when your undies start changing colour due to the weather we go to that sail. Note that this generation option is very weather dependant.

 

Towing one of those drogue things could make a knot or 2 difference at key times, a noticeable difference at all times unless it's blowing it's tits off. One of those Wind N Waves (??) ones on the back of a lightweight 9.5mt yacht cost that boat a knot when at cruising speed, more in the softer weather. This option is also very weather dependant as you need speed to get a decent output.

 

Adding powered generation to run a built in unit would mean putting on MINIMUM of 80kg if on the TT startline. Not to mention having a AP that puts out 58 decibels whenever it's turned on. This option is partially weather dependant but I'm working on making it less so i.e being able to run it inside out of the weather.

 

80kg being a 22kg genny (Honda 2kw), 60lts of fuel and a pile of tote tanks. That will generate 8.3Amps 12V. The (NGK) AP unit I'd fit the Mini 650s calculate as using 7amps.

 

It would be nice to have the ability many have in no restrictions but not all of us do.

 

First world problems, how do we get thru each day :D

Link to post
Share on other sites

KM, I don't agree with all of that. The Mini 650's are pretty similar to what you are trying to do. A reliable self steering system with minimum drag and min weight... They often use a hydraulic system. Here is a pic of one;

61300d1316016685-homemade-autopilot-mini

 

Similar to the unit pictured, the Navico HLD350 mk2 split version drive weighs approx. 9KG. The Compass, AP computer and rudder sensor are less than 3KG. Power requirement is 3.5-10amps depending on load. Average draw is towards the lower end. a 200 amp hour lithium bat  is in the region of 32 KG - but pricey! Really fast charge rates, heaps of cycles, 70% lighter than the equivalent wet cell battery.

 

The main issue as I see it for a small, light race boat is recharging. KM, be careful of those little gensets - often have say 2kw output IN 230V ONLY and a small trickle charge in 12-15v for batt charging - sometimes only 8amps odd. So to make them work, you have to have them, AND a mains battery charger to get decent DC output, with additional weight and losses in conversion.

 

Still the largest output for the least weight, IMO, is a good alternator - IF you have an engine (small diesel?) to drive it. If not, say you have an outboard only, then it is a real issue. A fuel cell maybe? How do the mini's manage this?

 

Oh, and also, as far as I can see, the mini 650's often use NKE as most mini's are French, and so is NKE. I cannot see a functional reason that they are better than any others - in fact they are not as clever as the top end B&G models.

Link to post
Share on other sites

" in fact they are not as clever as the top end B&G models"

 

NKE developed very clever systems for the big solo trimarans that "know" enough to, for example, bear away when overpowered off the wind, and also release sheets when required, but not when not needed to, clever stuff indeed. So the solo sailor never needs to steer.

 

tb

Link to post
Share on other sites

Yep, I agree with that TB, the B&G stuff was developed with monos in mind - using and for the Vendee globe boats - same thing, the APs steer virtually all the time. They have gust response and crash recovery etc built in - not something you need (or want!!) in a multi!  

Link to post
Share on other sites

How much juice you need? Fuel cell will do 80-110w/hr in a 9kg footprint, 4.3kg 5L fuel can will give you 5.5kwh and will run near silent for 2 days. If you can spec an AP to within that loading you'd have a win

Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.


×
×
  • Create New...