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skipperaris · 21-02-2007, 00:33

Thank you very much guys. You are all adding to my meagre store.

Climb the mast pwederell? There as a time when I could. Nowadays I would need help from someone on the deck. (Which reminds me of another project: Mast steps.) But I see what you are saying and yes a radar course sounds like a very good idea although I have used radar on other yachts. As I recall it is important to set it up right for Gain, Rain and sea every time you change the range you are looking at. Right?

Thanks for the caution senormechanico. I have also seen such things. This is a mistake it would be unforgiveable for me to make. My post grad work was on solar energy. The other bits will go round the solar panels not above them, not ever! The only thing that bothers me a little is how to make it easy to clean them from time to time. They do gather dust.

The idea at the moment is to climb up the side of the arch and have a go with the water hose and deck brush. Any thoughts?

**Alan Wheeler** · 21-02-2007, 00:58

You don't want to worry about the scanning of your deck. It can actually be a very good tool to "see" the water directly infront of you. When I was installing Koden equipment, the supplier took me on a product review weeked. We installed all the latest and greatest gear onto a boat. (Pete, you would be familiar with Infinity. Noel Parsons owned it at the time.) We went out to D'Urville Island and arrived late at night. It was pitch black. The first operation eye opener for me was the Skipper taking the bow of the boat right onto the mooring bouy in the pitch black dark. He viewed it all the way in with the Radar and brought the bouy right under the bow where a guy picked it up. This was no small boat, so a visual on the bouy was not possible for anyone till the boat was vertually right over top.
Coot has a very good analogy with Radar and flashlight. That is exactly what the Radar is. And electronic Flashlight. To better understand the Radar, just think of the Radar beam as the beam of a special spot light. The way the beam hits and bounces of a target is rather the same. Being able to "see" 16 miles is one thing and a good thing. But reducing surface clutter is another very important aspect. If you can not tune the Radar successfully, then it is next to useless. If the scanner is too low, the beam bounces back off the face of small choppy waves and the "surface clutter" can not be controlled as such. You either have too much clutter and targets disappear in the mess, or you turn down controls to reduce the clutter and then lose targets. With the scanner in the correct position, the best "noise to target" ratio is achieved.
Radar is kinda cool in that it does "wrap" around imediate objects like the mast and the mast becomes invisible to a point. It can create a blind spot on return signals however. Sails when dry are not an issue, but wet sails certainly can reduce the image dramaticaly. A sail is more than likely going to be wet in fogs and other situatons of poor visiblity. So it is a consideration to keep in mind.
I strongly recommend a "pedulum" to mount the scanner on. This is simple and easy enough to construct and is certainly available to buy. It simply keeps the scanner horizontal no matter what angle of heel the boat is on. This solves many of the issues that Coot correctly described in regards to the beam looking down at the water and up into the sky. The more horizontal the scanner remains, the more horizon it scans and the more returns and the more accurate those returns will be.
Colour Radar is certainly a major plus. If I could afford one, I woul dhave it. But I have found the B/W LCD to do most of what I need.

Raven · 21-02-2007, 02:34

Quote:

Originally Posted by Alan Wheeler

It was pitch black. The first operation eye opener for me was the Skipper taking the bow of the boat right onto the mooring bouy in the pitch black dark.

Quite frequently I return "home" to my mooring in darkness. The entrance to the 4-mile-long bay has a couple of buoys marking shoals. They are cleanly visible on the radar. Along the way, I can "see" the small boats that are running without lights (a bit foolish). As I get close to the end of the bay, I reduce the range and each boat in the mooring field paints out plainly on the radar as I slip through to pick up my pennant in the middle of them all. I don't have much for electronics aboard Raven, but I sure do appreciate the radar!

**GordMay** · 21-02-2007, 03:34

Cockpit Displays:
Generally, monochrome LCDs and color TFT’s work well in all lighting conditions, even bright sunlight, and are much easier to waterproof than the (higher resolution) CRT’s.

Some good on-line references:

Jason Sidaway (Raymarine Senior Products Support Engineer) offers his comments on Radar Scanner Installation in Yachting Monthly (April 2006)
Yachting Monthly - Any Questions: The higher the better for radar?

Chuck Husick offers his comments on Radar in BoatUS presents ...
Chuck Husick on BoatUScom

I offered some comments on calculating range in “VHF Radio Range”:
http://www.cruisersforum.com/forums/...range-376.html

Mounting Height:
Radar signal, like VHF signals, travels in a nearly straight line. Because a radio signal is slightly refracted, the Radio horizon (range, or radio dip) is slightly further away than a simple “line of sight”.
To calculate radio range, we add the two (D1 transmit & D2 receive) antennae ranges* together, thus:

Range = D1 + D2

hence

Range = (1.22 x Root Ht + (1.22 x Root Hr)

where:
Ht = Transmitter Height
Hr = Receiver Height
Distances are in nautical miles*, and heights in feet

* atmospheric and weather conditions can either increase or decrease these range distances.

Obviously, you are not going to be tracking most targets at the theoretical maximum range of 16 nm.

Greg S · 21-02-2007, 04:48

I have a Questus mount that came with the boat and it seems to work well, but I've heard both good and bad about them.

Questus Marine radar automatic leveling system prevents target loss when heeling.

skipperaris · 21-02-2007, 09:52

It is "back to the drawing board" with everything I read, over here.

That's a lot of information Gord!

The Questus device looks right but it costs about as much as my radar cost me. What is the bad you heard GregS?

There must be an Ozzy making something similar twice as good at a fraction of that price.

Is it too daring to think of making something like this myself?

Greg S · 21-02-2007, 11:52

The bad, and this is at least third of forth hand information, is...

1. Under the right conditions, with the boat rolling from side to side, the dampening motion of the mount sets the system into a (?) non resonant frequency. IE: by the time the mount and raydome starts to recover form a starboard roll the boat is already entering into a port roll, the result of which is very a minimal window for the radar to get a good level look at things. I've never had the boat out in those conditions, but don't doubt that it could happen.

2. Because of the swinging motion of the mount the cable to the antenna tends to wear out. (I put put chafe guard on mine and will carry a spare)

3. The mount itself will wear out. (Things wear out on a sailboat!?!?

)

Some of this is covered on the Questus web page, as well as all the good points of their of mount. There are other manufacturers this type of system out there. Waltz Mfg. and Yacht Specialties are two.

Doesn't it always seem to be the case that just when you think you have it figured out you find what seems to be a better way? And... it always costs more than you thought!

Good luck with it Skipper!

senormechanico · 21-02-2007, 13:35

Quote:

Originally Posted by skipperaris

My point about the 15 degrees was that the radar beam is not "wasted" scanning my deck which would be the case regardless of heel if the radome is low down.

Basically the higher the scanner, the greater the range, but at a price of close up target recognition (dinghy, channel markers etc.)

Long radar range sounds nice, but you'll spend most of the time on the 2 to 8 mile range. Something to think about: when you're winding your way through a foggy narrow channel, it's kinda freaky when the next channel marker just disappears from your screen just when you're getting close!

Steve B.

skipperaris · 22-02-2007, 16:31

Quote:

Originally Posted by Greg S

2. Because of the swinging motion of the mount the cable to the antenna tends to wear out. (I put put chafe guard on mine and will carry a spare)

Doesn't it always seem to be the case that just when you think you have it figured out you find what seems to be a better way? And... it always costs more than you thought!

Good luck with it Skipper!

I have thought about all this and am going to make my own levelling thingy. So your wish for good luck is very very welcome.

I thought of the cable wearing out and having manhandled my cable I think that if it is subjected to torsion rather than bending it should last longer and might help dampen the port/starboard swings. Could be wrong of course.

Quote:

Doesn't it always seem to be the case that just when you think you have it figured out you find what seems to be a better way? And... it always costs more than you thought!

Too true, but there is no way I'll pay the price of a second radar for the cymballed mount. My cooker stays level - never spilt a drop of soup - for god's sake! Although a cooking pot has been known to crash down on the floor when not secured with the fiddles and a sneaky wave has hit ...

After all in my experience, a sailing yacht gets into a heel and stays there most of the time although a following sea could get the radome swinging.

Anyway, my bank manager is a nice guy. I would hate to upset him.

Quote:

3. The mount itself will wear out. (Things wear out on a sailboat!?!?

)

Everything does. Exactly what I thought while I was checking out my hairline (euphimism) this morning...

Anyway I will keep notes while making this and take pictures to post when it is done and deemed a success, for anyone interested.

BTW Yacht Specialties do not seem to have a self levelling radome base. (I'm not complaining!)

skipperaris · 22-02-2007, 16:40

Quote:

Originally Posted by senormechanico

Basically the higher the scanner, the greater the range, but at a price of close up target recognition (dinghy, channel markers etc.)

Long radar range sounds nice, but you'll spend most of the time on the 2 to 8 mile range. Something to think about: when you're winding your way through a foggy narrow channel, it's kinda freaky when the next channel marker just disappears from your screen just when you're getting close!

Steve B.

As it looks right now the radome is going to the stern. Taking what you say into consideration what would you say if the radome goes on a telescopic mount?

senormechanico · 22-02-2007, 18:46

"The only thing that bothers me a little is how to make it easy to clean them from time to time. They do gather dust.

The idea at the moment is to climb up the side of the arch and have a go with the water hose and deck brush. Any thoughts?"

That's an important facet of the mounting design for sure.
On Grey Max, our Lord Nelson 35 I made a cockpit arch which held 8 solar panels, each one was 13" x 53". Also in the mix was a homemade hot water panel, but that's another story. The whole thing was designed so I could stand on the 1" diameter ss. lifeline rail and, with a bucket, sponge and short brush, reach the whole array. I once figured the improvement in electrical output vs the electricity needed to produce the water needed to clean it was a plus.

Sorry for the bad pic. I had to take a digital photo of an existing photo.
The camera automatically flashes on macro, so I covered the flash with a piece of paper. At least you can get the idea of size of the array.

The full boat awning is up as well. For scale, those are a couple of 10' inflatables.

I cleaned the panel array about once a week while we were in Mexico, but made sure to do it either first thing in the morning or about dinnertime. Those things could get really hot!

Steve B.

skipperaris · 23-02-2007, 13:12

senormecanico

The pic is very adequate, no need to apologise.

That's a lot of solar. Must have cost a few $$$ to get all those. I imagine the hot water was a DIY? Presumably there was a tank for the hot water. Would be interested to know how you circulated it.

senormechanico · 23-02-2007, 19:43

I used a 12 volt March magnetic drive pump (teed into the fittings and located near the hot water tank in the engine room) to circulate the pressurized hot water. A differential controller with a sensor on the top of the tank (under the insulation of course) and another sensor on the output of the homemade solar panel. Whenever the solar panel sensor was hotter than the sensor on the tank, the pump ran. Hot output went into the tank hot output, and the tank's cold input line ran to the pump's input and then to the panel.

The panel was made with 1" aluminum angle for a frame with 1/2 inch of rigid foam covered on the bottom with sticky vinyl shelf liner for the bottom surface (facing the cockpit). Over the foam is a thin sheet of copper, painted black. On top of that is 1/2 copper pipe also painted black as you can see in the pix.
The whole mess is covered with a sheet of acrylic and fastened with nylon bolts. I teed in a vent as well to burp the air which very slowly collects. It needs to be burped about once every couple of weeks, but it really puts out the hot water in a sunny climate. You can take a hot shower anytime day or night.

The white pipe is a pass thru for the backstay.

Steve B.

skipperaris · 25-02-2007, 17:13

Very interesting senormechanico. I bet you had fun making this. What are the overall dimensions of this baby?

Shall I also ask how you routed your pipes and wires?