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Old 01-02-2008, 12:58   #16
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You need a bigger alternator and 3 stage regulator with an 800AH battery bank.
With an adler-barbour you will probably use around 70ah's per day...the electronic autopilot in calm weather might draw 4 amps or around 100ahs per day? Add the lights and other instruments to that and you can see needing 200ah to put back in each day. You ain't gonna do that with an 80amp/standard regulation alternator. I would get something around 110/120...no higher...to allow you to put back 200ah's in a couple of hours. (Note...it will take a LOT longer to "top up" to 100% but you can simply drain and charge between 60 and 80% "full" on bulk charge rate in a couple of hours this way...and wait to top up until you are actually needing to motor for a few hours.
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Old 01-02-2008, 14:20   #17
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I have done the second half of your planned voyage, but not solo, and not on my own boat. The boat I was on had a below-deck autopilot was constantly working despite balanced sails and was a tremendous power drain. I have a windvane on my boat and am amazed at how much better it is at steering a boat to weather than an autopilot, and with no power drain. I'm sure I could McGyver something up if the windvane somehow broke, but a broken autopilot would probably stay broken - something that would be rather "inconvenient" if you were solo with nothing around but water for a thousand miles in any direction.
Going solo, you are going to have to sleep sometime, and you'll have to trust you angels, so give them all the help you can with a mast-top tricolor. A light anywhere above the horizon can be seen if anyone on another boat or ship is watching on a dark night, whereas even white sails are invisible. Still risky, but definitely a little less so that running dark.
BTW, a Tricolor is legal, but not with deck running lights. Wire the tricolor through a switch so that you can select either or, but not both. (Anchor light between the west coast and Hawaii? ou must have an awful lot of anchor line!)
I don't think that increasing you alternator output is going to help much as the regulator is going to drop the charging current not long after starting to charge. Larger battery bank would help, and doing an energy analysis will clearly show that the refrigerator would best be Off during the passage.
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Old 01-02-2008, 15:28   #18
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Cool, I got invited to help out on a cruise to Hawaii in the next few month, and I wasn't sure if I'd be able to get my passport in time. Hopefully I won't need it.
There is no difference in crossing the border from California to Hawaii than crossing from Oregon to California. No passport required if you are a US Citizen.
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Old 01-02-2008, 16:10   #19
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Aloha All,
There is a regulation about running lights for a reason. The reason is so that you can be seen at sea if a proper lookout is kept on the "seeing" vessel.
I don't want to turn this into a p---ing contest. Yes, I ran my running lights (bicolor on the bow pulpit and white at the stern) and when my batteries started to drain I started my old Perkins to recharge.
I only used an anchor light when at anchor. I think a tricolor at the top of the mast is a wonderful idea but I didn't have one and not all vessels are small enough to qualify to use them. I had a strobe and if I thought another vessel was approaching too close I turned it on.
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Old 01-02-2008, 16:15   #20
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There is no difference in crossing the border from California to Hawaii than crossing from Oregon to California. No passport required if you are a US Citizen.
Cool, I had never done it before, so I wasn't sure. You never know with how insane the Department of Homeland INSecurity has gotten over the years. I'm enjoying this talk about alternators and LED lights also. I'm probably going to buy a new ComPac 35 to do this same passage this summer, and I'm going to try to get it outfitted with LEDs everywhere I can. What exactly is a tri-color mast light for? I'm a total noob with all the sailing terminology, so forgive if I ask stupid questions.
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Old 01-02-2008, 21:54   #21
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Gobi,
A tricolor light combines the port(red), starboard (green), and aft (white) running lights into one unit that is placed at the top of the mast. It usually also incorporates an all-around white anchor light. Being higher, it is visible over the horizon from farther away than the deck height running lights which often disappear behind waves.
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Old 01-02-2008, 22:18   #22
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Once you are sure of the power you will need it will not be tough to size accordingly. A smart alternator or smart charger is worth checking out - gets the most power into the cells in the least time. It be good to be able to have your radar on, at least sweeping every x amount of time.
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Old 01-02-2008, 22:20   #23
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And mind the quality and proper sizing of wiring and installation. It's simple but needs to be done to codes that will protect you.
That's gonna be a fun trip!
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Old 02-02-2008, 00:51   #24
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Rules 21-22 in COLREGS says, Mast-Top (<12m) Tricolor can be carried while sailing. I believe that the (<12m) means that vessels to 39.4 feet can carry a tricolor while sailing (not under power). So, a Compaq 35, would be good to have a tricolor but you would also need either side lights or a bicolor and a masthead(steaming) and stern light for while you are under power at night.
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Old 02-02-2008, 08:16   #25
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`have you looked into the cape horn windvane. These allow you to offset the windvane so that they will not interfere with swim steps. Here is a link Cape Horn - Integrated Self-Steering System for Sailboats
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Old 02-02-2008, 19:04   #26
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IMHO,
If you tow a water impeller you will keep your batteries topped with plenty to spare. No need to have an airplane propeller in your head all day. I think they have some that are dual purpose, both for water and wind.

Lights are a must. No one will see them at 20 miles out, but then again, no one will run you down from 20 miles out. You want to be visible in the danger zone, 5 miles to 2 miles out which is plenty of time for someone to blow the horns or take evasive action. Even the freighters doing 30 knots can avoid you at that distance.

The best radar reflector for the dollar and power drain is aluminum paper stuffed high in the mast. Nothing beats a windvane for steering.

J
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Old 03-02-2008, 01:25   #27
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The best radar reflector for the dollar and power drain is aluminum paper stuffed high in the mast
I'm going to have to disagree with this, and if pressed I could point to some decent research on the subject. Please do look at the data, but all considered the tried-and-true "corner reflector" design is probably the way to go. For example, the Davis: Davis - Marine - Deluxe Hanging Radar Reflector. There are some others that may be better (except for cost and weight), and there are definitely several well-known products that are essentially useless.
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Old 03-02-2008, 10:32   #28
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I'm going to have to disagree with this, and if pressed I could point to some decent research on the subject. Please do look at the data, but all considered the tried-and-true "corner reflector" design is probably the way to go. For example, the Davis: Davis - Marine - Deluxe Hanging Radar Reflector. There are some others that may be better (except for cost and weight), and there are definitely several well-known products that are essentially useless.
Hello Paul,

Lets us agree to disagree.

The bottom line is that the performance of radar reflection is directly proportional to its "linear" size to the 4th power and, its cross section area.

The bigger the area, the better the chance, the greater the heel, the less the chance. Blindspots can sometimes be huge when heeled. This of course is all related to passive reflectors. For a corner design, only one quarter may be viewed at any given time as would a linear design, but the linear design will have greater section area.

Indeed, the reflector you denote does not overly impress me at all as denoted by their own documentation and I quote,

http://www.davisnet.com/product_docu...RdrRfr_INS.PDF

"
(12 sq. meters) of maximum effective radar cross section in the X or 3 cm
band (9–9.6 GHz frequency), based on optimum orientation

between the reflector and radar."

The optimum is of course a sea state like glass; reflective corners are absolutely level and plumb; 100% visibility and 0% of interference whether aerodynamic or hydrodynamic with the reflector at the highest possible point on the mast; having being recently cleaned and buffed to a high reflective shine. Then, it costs $75.00 and can be blown away while being bent or hanked. Divide that by four quadrants and you have 3m^2 of reflective area at any given time.

A mast stuffed with wadded aluminum is "linear" and "vertical" by nature and its cross section at any heel will always be greater than the spherical reflector. This is also true from any direction because it will scatter the reflected band in all directions creating a huge "blip", oppossed to the round reflector which may even for that slight second be obscured by the mast and will only reflect in one direction.

Here is research denoting how poor these "spherical" engineered reflectors performed. Indeed it goes on to say that offshore use is marginally recommended for any of the products, "but something is better than nothing".

1995 Radar Reflector Test

Here is another denoting again that cross section is key.

Aerospaceweb.org | Ask Us - Radar Cross Section

Here is one denoting that any reflector with less than 10^2m of echo area is useless. That is TEN SQUARE METERS! Take a look at their products...they look linear to me and these are accepted for military use.

Echomax Radar Reflectors - Marine Regulations & Rules

I agree that "corner" reflectors with faces perpendicular to each other are the best planform for a reflector, because they are, if they are trihedrals. However, a "linear" reflector produces greater visible cross section at all times and an equivalent corner reflector would have to be colossal. As an example, a 1 foot wide mast will provide 1m^2 every 3.25 linear feet. Stuff the top 32.5 feet and you will paint on any radar 10 miles out like a starburst, even if you are in a 26 foot trough, which would give you the same 3m^2 sticking out over the crest.

If you can demonstrate that a linear reflector with greater cross section is inferior to non linear with small cross section, and that they are better for the cost, then I retract my initial statement and stand humbly corrected.

In the end, 12 "empty" beer cans hung high on the mast or a deck cannon to disburse "chaff" into the sky on a foggy night with horns blasting all around you will let the radar see you before they run you down because the watch was asleep.

J
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Old 03-02-2008, 11:06   #29
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Radar Reflectors

J,

I've seen some of these studies before -- let me review them again and see what else I can find. Perhaps the "wadded aluminum foil" suggestion isn't that bad, but let me ask:

* How much?
* Inside a typical aluminum mast??? I can see where it might be useful inside a wooden or composite mast, but even then, the horizontal cross-section is going to be pretty small.
* This mast has to be hollow with external halyards, correct?

Here is a link to an "Ocean Navigator" letter in which the author has measured (in a radar anechoic chamber) a 12-inch diameter plastic bag full of crumpled aluminum: Aluminum foil as an emergency radar reflector | Articles |. His measurement results were not encouraging. Of course, this is not exactly the same thing as you are suggesting, but it does have some similarities.
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Old 03-02-2008, 12:19   #30
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J,

I've seen some of these studies before -- let me review them again and see what else I can find. Perhaps the "wadded aluminum foil" suggestion isn't that bad, but let me ask:

* How much?
* Inside a typical aluminum mast??? I can see where it might be useful inside a wooden or composite mast, but even then, the horizontal cross-section is going to be pretty small.
* This mast has to be hollow with external halyards, correct?

Here is a link to an "Ocean Navigator" letter in which the author has measured (in a radar anechoic chamber) a 12-inch diameter plastic bag full of crumpled aluminum: Aluminum foil as an emergency radar reflector | Articles |. His measurement results were not encouraging. Of course, this is not exactly the same thing as you are suggesting, but it does have some similarities.
Hello Paul,

I believe you are 100% correct about the material sir. My mast was hollow wood when I had a 36mile radar test the foil inside of it. I stand corrected about material. I suspect that the aluminum mast may cause some "opaque" interference issues and may not be suitable, but I don't know. I might ask a marina owner to let me stuff a condemned mast and have someone shoot it to see. Yes, everything would have to be external.

Actually, it probably cost at least the amount to buy the Davis...but the cost was really half because the foil had already been used to cook something, so its dual purpose reduced costs by 2. Thats my story and I'm sticking to it.

Radar waves will disburse upon their journey and the curvature of the earth will limit their distance to objects on the horizon. I think the rule of thumb for wave existense is 1300 miles for every yard above water level. Their disbursement begins from the minute the pulse is generated and will only return if they encounter a perpendicular target to the wave whether it is above or below. For any radar to begin to be effective, it requires a pretty large area of perpendicular reflection. A radar that is at 100' height will not recept objects only at that height. Those are the optimal objects and most everything else is considered cluter, but not if it is painted "big" enough. The resolution will depend on the width of the beam and distance to target.

The masts height will eventually be found by a wave and if 20 feet of it reflects back...bang, starburst...starlight. It may still be like finding one krill in the ocean, but with more krill, the better the chance. At 20 feet of height the top of the mast may encounter a wavelength from 8666 miles away if conditions are optimal, which they never are, and those kinds of ranges are generated only by military early detection systems, but do you see the point of the height "linear" and area?

Reverse calculations, for a 24 mile radar, with optimal conditions, will paint an object at .1 yards height, so it is at the outermost/weakest limit of the wave life.

I will look at the study you denote. Its been a long time since I studied all of this and memory fails me horribly. Either way, there is no substitute for a watch at all times and the false sense of security from radar reflectors should not be entertained. Do we agree on that?

J
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