Good info in the previous postings, but one thing no one mentioned is something that sometimes confuses new radio owners. If you just turn on your radio and dial around you aren't likely to pick up anything interesting. It's not like a car radio where stations broadcast non-stop programming and you can tune in any time. Hams informally agree to "meet" on a certain frequency at a certain time each day. We call these meeting places "nets", so you have to know in advance that such and such a net meets at 8 AM on a certain frequency. At certain times of the day some frequencies don't work at all and then at another time they "open" up. This has to do with atmospherics. The nets usually start shortly after a certain frequency opens up. If you tune to that frequency before it opens all you'll hear is probably static. Likewise after it "closes". You can arrange in advance with another boat or person to "meet" at a certain time on a certain frequency if you want to talk one on one and not go through a net. If you just turn on the radio and dial around, it would be a fluke if you heard boats talking to each other.
Tom
KC6PPG
Shortwave Questions....
Moderator: Jim Walsh
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Scott MacCready
- Posts: 208
- Joined: Feb 5th, '05, 21:53
- Location: Previous Owner of CD30-ketch, CD26 #29, and CD25 #635 Hulls Cove,ME
- Contact:
Thanks for all the info. It does sound like a fun extension of living aboard. As you know, I'm currently up in Maine until so won't be spending a lot of time on the boat until I head south in March. In the meantime, would something like a yachtboy 400 enable me to listen in on very much? I don't know what the range on a portable radio is. thands, Scott
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barfwinkle
- Posts: 2169
- Joined: Feb 6th, '05, 10:34
- Location: S/V Rhapsody CD25D
YB 400
Is a pretty good radio. You should be ale to listen to just about anything. I used a Radio Shack DX 39? (394 or 6) to learn Morse Code and to listen to the marine nets. However, you may or may not need an external antenna.
Happy Holidays.
Happy Holidays.
Bill Member #250.
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Scott F
- Posts: 50
- Joined: Nov 20th, '05, 17:37
- Location: Minnesota, Interested in Cape Dory TY and TY Sr.
I Had Been Thinking About Putting an IC-706 onboard
so I could go out sailing for several hours, anchor in the lee of the island or pennsula, fire up the IC706, and work 20, 18, 10 meters.
I've never had a good feeling about finding a good RF ground to load up the backstay against. I've wondered if you could attach a weight to the end of a wire, and toss it in the water, right under the point where the backstay attaches to the boat, or where a mobile vertical antenna is mounted to the boat, and use that as a counterpoise.
I've never had a good feeling about finding a good RF ground to load up the backstay against. I've wondered if you could attach a weight to the end of a wire, and toss it in the water, right under the point where the backstay attaches to the boat, or where a mobile vertical antenna is mounted to the boat, and use that as a counterpoise.
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fenixrises
- Posts: 450
- Joined: Feb 13th, '05, 08:01
- Location: SunShine S2 11c
- Contact:
For Scott
Hi Scott,
Suggest you check out this page:
http://cruisenews.net/cgi-bin/mmham/web ... /read/1029
Good info from a very experienced ham.
Generally thier site http://cruisenews.net/cgi-bin/mmham/webbbs_config.pl is a gold mine of info.
Happy sails to you,
Fred B
Suggest you check out this page:
http://cruisenews.net/cgi-bin/mmham/web ... /read/1029
Good info from a very experienced ham.
Generally thier site http://cruisenews.net/cgi-bin/mmham/webbbs_config.pl is a gold mine of info.
Happy sails to you,
Fred B
You should always have an odd number of holes in your boat!
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Parfait's Provider
- Posts: 764
- Joined: Feb 6th, '05, 13:06
- Location: CD/36 #84, Parfait, Raleigh, NC
berthed Whortonsville, NC
Andy - We Need You
I am hoping that Andy will jump in here, but I know enough to tell you that you need foil grounding straps rather than wire in order to provide lots of surface area for the radio frequency currents to flow. While DC likes solid bars and AC can survive rather well in the same media, RF requires surface area and that is most easily arranged with copper foil. I have tried tinned braid with success in dry environments, but it is a compromise; better to use foil and protect it from the environment.
Keep on sailing,
Ken Coit, ND7N
CD/36 #84
Parfait
Raleigh, NC
Ken Coit, ND7N
CD/36 #84
Parfait
Raleigh, NC
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barfwinkle
- Posts: 2169
- Joined: Feb 6th, '05, 10:34
- Location: S/V Rhapsody CD25D
-
Parfait's Provider
- Posts: 764
- Joined: Feb 6th, '05, 13:06
- Location: CD/36 #84, Parfait, Raleigh, NC
berthed Whortonsville, NC
No capiche?
No capiche? I knew we needed Andy. I think he can provide the French translation. Maybe Danish too.
Keep on sailing,
Ken Coit, ND7N
CD/36 #84
Parfait
Raleigh, NC
Ken Coit, ND7N
CD/36 #84
Parfait
Raleigh, NC
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Andy Denmark
- Posts: 630
- Joined: Feb 5th, '05, 11:38
Okay, okay -- here's the best I know
If you attended the 2003 SSCA gam and WR & CC picnic two years ago in Melborne, FL, you would have gotten the latest on this. I can't tell you a site because the info came from a presenter at the session on ham radio installations on sailboats. His focus was primarily on PACTOR email systems but the principles of antenna/ground systems are the same regardless of the transmission mode.
I was on the verge of doing the copper strip, max surface area, thing on both my Bowman 36 ketch and CD-27 and decided that this braid method was simple enough to try and if it worked, great, because it was simple and inexpensive, and if it didn't, well, it didn't cost that much to try. It worked just fine.
The secret is NOT to use copper strips anywhere but use 1" tinned copper braid instead. It is available from Cable Experts and other supply houses (you can look up their ads in QST as well as I can -- 800 nos.) This stuff "rolls up" to fit in a #6 Ancor lug and is easily soldered. The holes in the lug can be any size you need. I suggest you use the correct size for the bolt you put these connections on and then liberally coat the connection with liquid tape. Use this braid for all your ground connections, not wire or copper strapping (It's the braid that keeps the surface area maximized and the impedance low).
The mistake most people make is to think the more points they can ground stuff to the better ground they will get. Wrong! The "ground loops" will drive you crazy if you have multiple connections. Here's what was recommended and what I did. I put a grounding plate (Dynaplate?) as close under the SGC-230 autotuner as physically possible and still keep it in the water (yes, you must haul the boat to do this right). Nothing else attaches to this plate. Mine is about 3" X 12" (guess) and has the shortest run possible (< 1 ft) to the ground lug on the tuner. Another ground strap goes from this grounding plate to the ground bus at the XCVR (about 12 ft) that also picks up the Gnd on the SCS PTC-lle (modified for PACTOR lll), and the negative PWR Gnd at the XCVR. Keep this second strap as short as possible.
Personally, I do not like Dynaplates. The connection to the bolt that goes through the hull and "bonds" with that stupid "gold" liquid that's furnished with the Dynaplate is not good. Test it with an ohmeter after it's been in the water a year and it will be a high-resistance short rather than a solid connection. It doesn't seem to affect RF much, though so maybe I'm wrong about this.
In any case, I'm having a local machine shop make me a new plate from beryllium copper with a pair of threaded studs of the same material that will be silver soldered to the plate for a solid connection. This is strong stuff and also corrosion resistant being a copper alloy. The washers and nuts are of the same material (but I haven't found a source for them yet 'cause I haven't looked. I know they are available as I used them in a former life.)
A word of warning. The tinned copper braid will corrode in a salt air environment and turn grey-green. ABYC says it isn't to be used for power circuits anywhere on a boat. I suspect it would eventually corrode away so I'm going to replace all of mine and either laminate it to the hull with West system epoxy and coat it on the free runs with Liquid Tape or perhaps even simply paint the stuff. Even corroded the braid seems to do its thing and the above treatments are just to make permanent what has been an experimental system.
Technically, the braid is a very low impedance ground connection to the water, making the water surface an efficient ground plane (salt water only, though? -- I wondered). The low impedance minmizes RF radiation yet provides a low resistance connection to the water. Of course there will be places where ferrites need to be used at the XCVR, tuner, and especially at the computer if you're going to use PACTOR. Where these go differs for every installation. There is some stray RF in every antenna system. For the most part, this system is just like any longwire antenna in this regard and the stray RF will vary with operating frequency, antenna length, SWR, and coupling ciruitry.
Gordon West says any thru-hull, propeller shaft, or grounding plate can be used but with more boats leaving their AC equipment running 24/7, I'd be afraid that some A/C might cause some electrolytic degradation of the fitting. Go for fail/safe wherever possible.
________
Lyme Disease Advice
I was on the verge of doing the copper strip, max surface area, thing on both my Bowman 36 ketch and CD-27 and decided that this braid method was simple enough to try and if it worked, great, because it was simple and inexpensive, and if it didn't, well, it didn't cost that much to try. It worked just fine.
The secret is NOT to use copper strips anywhere but use 1" tinned copper braid instead. It is available from Cable Experts and other supply houses (you can look up their ads in QST as well as I can -- 800 nos.) This stuff "rolls up" to fit in a #6 Ancor lug and is easily soldered. The holes in the lug can be any size you need. I suggest you use the correct size for the bolt you put these connections on and then liberally coat the connection with liquid tape. Use this braid for all your ground connections, not wire or copper strapping (It's the braid that keeps the surface area maximized and the impedance low).
The mistake most people make is to think the more points they can ground stuff to the better ground they will get. Wrong! The "ground loops" will drive you crazy if you have multiple connections. Here's what was recommended and what I did. I put a grounding plate (Dynaplate?) as close under the SGC-230 autotuner as physically possible and still keep it in the water (yes, you must haul the boat to do this right). Nothing else attaches to this plate. Mine is about 3" X 12" (guess) and has the shortest run possible (< 1 ft) to the ground lug on the tuner. Another ground strap goes from this grounding plate to the ground bus at the XCVR (about 12 ft) that also picks up the Gnd on the SCS PTC-lle (modified for PACTOR lll), and the negative PWR Gnd at the XCVR. Keep this second strap as short as possible.
Personally, I do not like Dynaplates. The connection to the bolt that goes through the hull and "bonds" with that stupid "gold" liquid that's furnished with the Dynaplate is not good. Test it with an ohmeter after it's been in the water a year and it will be a high-resistance short rather than a solid connection. It doesn't seem to affect RF much, though so maybe I'm wrong about this.
In any case, I'm having a local machine shop make me a new plate from beryllium copper with a pair of threaded studs of the same material that will be silver soldered to the plate for a solid connection. This is strong stuff and also corrosion resistant being a copper alloy. The washers and nuts are of the same material (but I haven't found a source for them yet 'cause I haven't looked. I know they are available as I used them in a former life.)
A word of warning. The tinned copper braid will corrode in a salt air environment and turn grey-green. ABYC says it isn't to be used for power circuits anywhere on a boat. I suspect it would eventually corrode away so I'm going to replace all of mine and either laminate it to the hull with West system epoxy and coat it on the free runs with Liquid Tape or perhaps even simply paint the stuff. Even corroded the braid seems to do its thing and the above treatments are just to make permanent what has been an experimental system.
Technically, the braid is a very low impedance ground connection to the water, making the water surface an efficient ground plane (salt water only, though? -- I wondered). The low impedance minmizes RF radiation yet provides a low resistance connection to the water. Of course there will be places where ferrites need to be used at the XCVR, tuner, and especially at the computer if you're going to use PACTOR. Where these go differs for every installation. There is some stray RF in every antenna system. For the most part, this system is just like any longwire antenna in this regard and the stray RF will vary with operating frequency, antenna length, SWR, and coupling ciruitry.
Gordon West says any thru-hull, propeller shaft, or grounding plate can be used but with more boats leaving their AC equipment running 24/7, I'd be afraid that some A/C might cause some electrolytic degradation of the fitting. Go for fail/safe wherever possible.
________
Lyme Disease Advice
Last edited by Andy Denmark on Feb 13th, '11, 03:22, edited 1 time in total.
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Parfait's Provider
- Posts: 764
- Joined: Feb 6th, '05, 13:06
- Location: CD/36 #84, Parfait, Raleigh, NC
berthed Whortonsville, NC
Surface Area is the issue
Scott,
You have created a monster. Now that we have Andy giving up his hard-won secrets of grounding, I am digging into the physics. Can this be good in any way at all? Am I really this anal?
First, it needs to be said that RF travels on the surface of the wire, not inside, and that the current is very low; therefore, surface area is most important.
At http://www.amgndsys.com/braids.htm we find the specs for various forms of braid. These may not be the specs for Andy's braid or anything anyone else has used either, but let's just say that they are probably representative. The "best" 1" braid I found in the list seems to use 384 individual wires for a total of 38,400 circular mils of cross section. The circumference of all 384 wires is about 1.21" total. If this is sufficient, then a 3/4 inch copper foil would be comparable and a 4" foil is more than 6 times better than the braid. This assumes that each of the 384 wires appear to the RF as if they were laid out flat, without touching one another, but this can't be true or it wouldn't be a braid. It would be interesting to know what a braid actually looks like RF-wise, but let's give it the benefit of the doubt and say it does look like 384 individual wires. Foil of the same width is better and 4 " foil is much better. It is also easier to protect with a coat of epoxy or gel coat or paint.
As for the Dynaplate, I think its most charming feature is that it is sintered bronze and has a surface area much greater than a similar-sized plate. They claim a ratio of 48:1, so a 3x12 plate looks like at least 12 sq. ft., but with the 3/4 in. thickness thrown in, they claim it appears to be 40 sq. ft. In an RF environment where surface area is king, it seems that the Dynaplate might have an advantage over a solid plate. See http://www.shipstore.com/ss/html/GUS/GUS4012.html
As for salt vs. fresh water, well, it has to do with conductivity. In very rough terms, sea water is 100 to 1000 times more conductive than surface water, depending on salinity, temperature and probably some other properties. I can't say that I found a great reference for this, but if someone does, I'd like to see it. Here's some conductivity values from Wikipedia:
Silver: 63.01 · 106 S/m (630,100 S/cm; highest electrical conductivity of any metal)
Sea water: 5 S/m
Drinking water: 0.005 – 0.05 S/m
Ultra pure water: 5.5 · 10-6 S/m
So that's my 2 cents worth for the time being.
You have created a monster. Now that we have Andy giving up his hard-won secrets of grounding, I am digging into the physics. Can this be good in any way at all? Am I really this anal?
First, it needs to be said that RF travels on the surface of the wire, not inside, and that the current is very low; therefore, surface area is most important.
At http://www.amgndsys.com/braids.htm we find the specs for various forms of braid. These may not be the specs for Andy's braid or anything anyone else has used either, but let's just say that they are probably representative. The "best" 1" braid I found in the list seems to use 384 individual wires for a total of 38,400 circular mils of cross section. The circumference of all 384 wires is about 1.21" total. If this is sufficient, then a 3/4 inch copper foil would be comparable and a 4" foil is more than 6 times better than the braid. This assumes that each of the 384 wires appear to the RF as if they were laid out flat, without touching one another, but this can't be true or it wouldn't be a braid. It would be interesting to know what a braid actually looks like RF-wise, but let's give it the benefit of the doubt and say it does look like 384 individual wires. Foil of the same width is better and 4 " foil is much better. It is also easier to protect with a coat of epoxy or gel coat or paint.
As for the Dynaplate, I think its most charming feature is that it is sintered bronze and has a surface area much greater than a similar-sized plate. They claim a ratio of 48:1, so a 3x12 plate looks like at least 12 sq. ft., but with the 3/4 in. thickness thrown in, they claim it appears to be 40 sq. ft. In an RF environment where surface area is king, it seems that the Dynaplate might have an advantage over a solid plate. See http://www.shipstore.com/ss/html/GUS/GUS4012.html
As for salt vs. fresh water, well, it has to do with conductivity. In very rough terms, sea water is 100 to 1000 times more conductive than surface water, depending on salinity, temperature and probably some other properties. I can't say that I found a great reference for this, but if someone does, I'd like to see it. Here's some conductivity values from Wikipedia:
Silver: 63.01 · 106 S/m (630,100 S/cm; highest electrical conductivity of any metal)
Sea water: 5 S/m
Drinking water: 0.005 – 0.05 S/m
Ultra pure water: 5.5 · 10-6 S/m
So that's my 2 cents worth for the time being.
Keep on sailing,
Ken Coit, ND7N
CD/36 #84
Parfait
Raleigh, NC
Ken Coit, ND7N
CD/36 #84
Parfait
Raleigh, NC
-
Andy Denmark
- Posts: 630
- Joined: Feb 5th, '05, 11:38
Physics, numbers, etc. -----
But I think you missed the point. Surface area of the foil is certainly useful when you're trying to capacitively couple through the hull to the water. I don't see it as having anything to do with the system I described.
Who knows how a flat surface behaves with RF? I don't pretend to be able to explain this with any engineering I ever did but if this system works because of low impedance of the braid then how is the impedance of a flat conductor measured and compared? Maybe there's a table somewhere for that -- I don't know.
As for the Dynaplate, it is hard to dispute the sales pitch for the sintered metal approach -- all those little beads connected in close proximity must have a large surface area. The problem, as I pointed out, is that it is virually impossible to keep the connection sound to the Dynaplate with the system they furnish. I've measured the resistance of this connection with some age on it just to see and it is a very high resistance, i.e., poor connection.
Lightning probably won't care. There's even a theory that lightning actually seeks out poor conductors (people, buildings, and trees) in lieu of good ones (towers, bridges, etc.) RF may care -- or not -- while a surface phenomenon, depending on frequency, it isn't the same sort of "surface pehnomenon" as lightning because of the orders of magnitude differences in current.
My method, with the beryllium copper plate with the same alloy threaded stud drilled and tapped into the plate and then silver soldered, is a solid connection to the outside plate and therefore the water. And it is the connection we're looking for, not surface area or a capacitively coupled foil-to-water counterpoise. In my method the water itself is the directly coupled counterpoise.
Using sheet copper instead of a solid wire or braid may or may not be effective here. Again, I don't know as I've only used the braid for this. I do know that bending this 4 inch wide sheet copper around complex turns, corners, irregular surfaces, etc. is not an easy or neat job. And getting the recommended 100 sq. ft of area against the hull (and keeping it there) is a near impossibility in boats as small as ours without an undue amount of work and hassle. While the foil system does work well it's a definite pain in the ass to do, especially compared to the one I described.
If you want a reference for this system (other than mine), I'll be glad to furnish same. PM me for name and email addresses.
I am trying to find the Gordon West article on this. He explains it better than I can.
________
Ford tempo specifications
Who knows how a flat surface behaves with RF? I don't pretend to be able to explain this with any engineering I ever did but if this system works because of low impedance of the braid then how is the impedance of a flat conductor measured and compared? Maybe there's a table somewhere for that -- I don't know.
As for the Dynaplate, it is hard to dispute the sales pitch for the sintered metal approach -- all those little beads connected in close proximity must have a large surface area. The problem, as I pointed out, is that it is virually impossible to keep the connection sound to the Dynaplate with the system they furnish. I've measured the resistance of this connection with some age on it just to see and it is a very high resistance, i.e., poor connection.
Lightning probably won't care. There's even a theory that lightning actually seeks out poor conductors (people, buildings, and trees) in lieu of good ones (towers, bridges, etc.) RF may care -- or not -- while a surface phenomenon, depending on frequency, it isn't the same sort of "surface pehnomenon" as lightning because of the orders of magnitude differences in current.
My method, with the beryllium copper plate with the same alloy threaded stud drilled and tapped into the plate and then silver soldered, is a solid connection to the outside plate and therefore the water. And it is the connection we're looking for, not surface area or a capacitively coupled foil-to-water counterpoise. In my method the water itself is the directly coupled counterpoise.
Using sheet copper instead of a solid wire or braid may or may not be effective here. Again, I don't know as I've only used the braid for this. I do know that bending this 4 inch wide sheet copper around complex turns, corners, irregular surfaces, etc. is not an easy or neat job. And getting the recommended 100 sq. ft of area against the hull (and keeping it there) is a near impossibility in boats as small as ours without an undue amount of work and hassle. While the foil system does work well it's a definite pain in the ass to do, especially compared to the one I described.
If you want a reference for this system (other than mine), I'll be glad to furnish same. PM me for name and email addresses.
I am trying to find the Gordon West article on this. He explains it better than I can.
________
Ford tempo specifications
Last edited by Andy Denmark on Feb 13th, '11, 03:22, edited 1 time in total.
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Parfait's Provider
- Posts: 764
- Joined: Feb 6th, '05, 13:06
- Location: CD/36 #84, Parfait, Raleigh, NC
berthed Whortonsville, NC
If Braid is Good Enough
If braid is good enough, then we certainly don't need to complicate the routing with foil, but we can't prove that unless we do the experiment. I have the foil, so I'll go with it.
Certainly the suface area is important if we are talking about capacitive coupling, but it is also important in an RF conductor. If surface area isn't important, then why run braid, why not just use solid 10 ga. with over 100,000 circular mils of cross section and 0.3 inches of circumference? You could even use stranded tinned Ancor at much less expense than the braid or the foil if cross section was the issue.
No dispute on the poor connection to the Dynaplate; if it is not a good RF connection, then it isn't going to work. I guess that is why people recommend capacitive coupling; it keeps all the connections inside the boat where they are less likely to corrode.
I can believe that lightning doesn't care about poor connections and will strike there before a good connection, but the basic idea behind lightning protection is prevention by bleeding the charge before the potential reaches the bolt state. Franklin might have been killed if a lightning bolt had hit his kite, but all the time the kite was flying, it was making the potential at the the kite close to the voltage potential at that ground, so his kite was no more likely to be hit than anything on the ground. Lightning arrestors are simple Franklin mechanisms that bleed the charge before it reaches monstrous proportions. They also happen to create a path in the event of a strike, but the main objective is to prevent the strike in the first place by bleeding the charge. Poor connections don't allow that to happen.
Maybe I'll install braid and foil so we can do A/B tests.
Certainly the suface area is important if we are talking about capacitive coupling, but it is also important in an RF conductor. If surface area isn't important, then why run braid, why not just use solid 10 ga. with over 100,000 circular mils of cross section and 0.3 inches of circumference? You could even use stranded tinned Ancor at much less expense than the braid or the foil if cross section was the issue.
No dispute on the poor connection to the Dynaplate; if it is not a good RF connection, then it isn't going to work. I guess that is why people recommend capacitive coupling; it keeps all the connections inside the boat where they are less likely to corrode.
I can believe that lightning doesn't care about poor connections and will strike there before a good connection, but the basic idea behind lightning protection is prevention by bleeding the charge before the potential reaches the bolt state. Franklin might have been killed if a lightning bolt had hit his kite, but all the time the kite was flying, it was making the potential at the the kite close to the voltage potential at that ground, so his kite was no more likely to be hit than anything on the ground. Lightning arrestors are simple Franklin mechanisms that bleed the charge before it reaches monstrous proportions. They also happen to create a path in the event of a strike, but the main objective is to prevent the strike in the first place by bleeding the charge. Poor connections don't allow that to happen.
Maybe I'll install braid and foil so we can do A/B tests.
Keep on sailing,
Ken Coit, ND7N
CD/36 #84
Parfait
Raleigh, NC
Ken Coit, ND7N
CD/36 #84
Parfait
Raleigh, NC
-
Andy Denmark
- Posts: 630
- Joined: Feb 5th, '05, 11:38
Gordon West reference
I Googled this and found the Gordon West reference. Here it is:
http://www.kp44.org/ftp/SeawaterGroundi ... onWest.pdf
________
Herbal Vaporizers
http://www.kp44.org/ftp/SeawaterGroundi ... onWest.pdf
________
Herbal Vaporizers
Last edited by Andy Denmark on Feb 13th, '11, 03:22, edited 1 time in total.
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Guest
-
johnny of STORK
- Posts: 97
- Joined: Feb 7th, '05, 18:51
- Location: Cape Dory 30 #240 STORK
Taos, NM
San Carlos, Sonora, MX - Contact:
MM Ham links
The best site I have found is:
http://www.geocities.com/bill_dietrich/ ... tionOnBoat
There is a lot of good info in the archives of this discussion group:
http://cruisenews.net/cgi-bin/mmham/webbbs_config.pl
These guys don't have much patience with "newbie" type questions such as this, but searching the archives will turn up a lot about RF grounding on a boat. That said, a lot of their opinions don't seem to agree on even this issue.
Personally, I have found that 2" wide strips of copper flashing (.020" th.) connecting the xmitter and tuner to a dynaplate (and the rest of the bonding system) gives a very good signal. For many years, I used a "Hamstick" antenna, and a ~10 foot length of 7x19 rigging wire trailing in the water for a ground, and was always able to get through to the U.S. somewhere from the Sea of Cortez.
Johnny of STORK
KJ5UR
http://www.geocities.com/bill_dietrich/ ... tionOnBoat
There is a lot of good info in the archives of this discussion group:
http://cruisenews.net/cgi-bin/mmham/webbbs_config.pl
These guys don't have much patience with "newbie" type questions such as this, but searching the archives will turn up a lot about RF grounding on a boat. That said, a lot of their opinions don't seem to agree on even this issue.
Personally, I have found that 2" wide strips of copper flashing (.020" th.) connecting the xmitter and tuner to a dynaplate (and the rest of the bonding system) gives a very good signal. For many years, I used a "Hamstick" antenna, and a ~10 foot length of 7x19 rigging wire trailing in the water for a ground, and was always able to get through to the U.S. somewhere from the Sea of Cortez.
Johnny of STORK
KJ5UR