Cruisers Forum
 


Reply
  This discussion is proudly sponsored by:
Please support our sponsors and let them know you heard about their products on Cruisers Forums. Advertise Here
 
Thread Tools Search this Thread Rate Thread Display Modes
Old 27-04-2021, 06:21   #1
Registered User

Join Date: Jul 2020
Location: Virginia, USA
Boat: Tayana 37
Posts: 151
So my boat lacks a lightning ground.

So my boat lacks a lightning ground. Not sure how that happened but I have double checked to make sure I am not crazy and it is true. The mast is tied directly into the DC negative bus which is turns goes to the electrical ground at the propshaft.

Not sure if this omission is original to the boat or something done by a prior owner. How big of a problem is this? I am thinking really big problem. My understanding is that there should be a separate lightning ground going to a ground plate in the water disconnected from the normal DC electrical system. As it exists now pretty sure a lightning strike would destroy the electrical system, batteries, and possibly engine.

Has anyone seen this before. It seems the fix would be simple (well it will require a haul out) so wondering why it wasn't done or if it was done originally why it was removed.
Statistical is offline   Reply With Quote
Old 27-04-2021, 07:03   #2
Registered User

Join Date: Jan 2014
Location: Panama City FL
Boat: Island Packet 32 Keel/CB
Posts: 780
Re: So my boat lacks a lightning ground.

Somebody just took the easy way out. You are embarking down a treacherous path (asking that particular question on this forum). You will get a wide variety of opinions. My suggestion (from someone that worked in the LP business for buildings), get a large copper plate (approx, 6 X 24 X 1/4") mounted on the exterior with 4 substantial silicone bronze bolts (say 1/2"), and connect it to the base of the mast with a pair of 1/0 tinned copper battery cables (your choice of insulation color) in the most direct and shortest path avaliable. Check in on the assy every few years to make sure corrosion has not taken over.

What I did, and sleep pretty well at night.

Do not refer in any way to this as a lightning protection system but consider it a lightning mitigation system. This is to protect the craft and it's occupants against a visit from Zeus. If he shows up really mad then all bets are off. Protection of your less valuable electronics is a bit of a crap shoot and much more complicated.


Frankly
Frankly is offline   Reply With Quote
Old 27-04-2021, 08:03   #3
Registered User

Join Date: Jul 2020
Location: Virginia, USA
Boat: Tayana 37
Posts: 151
Re: So my boat lacks a lightning ground.

Quote:
Originally Posted by Frankly View Post
Somebody just took the easy way out. You are embarking down a treacherous path (asking that particular question on this forum). You will get a wide variety of opinions. My suggestion (from someone that worked in the LP business for buildings), get a large copper plate (approx, 6 X 24 X 1/4") mounted on the exterior with 4 substantial silicone bronze bolts (say 1/2"), and connect it to the base of the mast with a pair of 1/0 tinned copper battery cables (your choice of insulation color) in the most direct and shortest path avaliable. Check in on the assy every few years to make sure corrosion has not taken over.

What I did, and sleep pretty well at night.

Do not refer in any way to this as a lightning protection system but consider it a lightning mitigation system. This is to protect the craft and it's occupants against a visit from Zeus. If he shows up really mad then all bets are off. Protection of your less valuable electronics is a bit of a crap shoot and much more complicated.


Frankly
Thanks for confirming what I suspected. Yeah the route you describe is what I have seen in Nigel's "Boatowners Mechanical and Electrical Manual". First time boatowner, I just kinda assumed it was there and we know what assuming does.

"Do not refer in any way to this as a lightning protection system but consider it a lightning mitigation system. "

That is a very good way to frame it. Keeps a bad event from being an even worse event.
Statistical is offline   Reply With Quote
Old 27-04-2021, 08:09   #4
Registered User

Join Date: Jul 2005
Location: Bellingham
Boat: Outbound 44
Posts: 8,820
Re: So my boat lacks a lightning ground.

How many years has it been like this?

Is this really the top of the list items you want to do on the boat?
__________________
Paul
Paul L is online now   Reply With Quote
Old 27-04-2021, 08:13   #5
Registered User

Join Date: Jul 2020
Location: Virginia, USA
Boat: Tayana 37
Posts: 151
Re: So my boat lacks a lightning ground.

Quote:
Originally Posted by Paul L View Post
How many years has it been like this?

Is this really the top of the list items you want to do on the boat?
I don't know how long it has been like this. It is a pretty niche thing to find out how it was originally done on a boat that is 40 years old. If it is original to the boat it has been like this for a very long time. I think it is more likely something done by a prior owner so it could be a lot less. I have only owned her for less than a year.

I don't anticipate it being a complicated fix. It will require a haul out so I will wait until this fall when I need to paint the bottom anyways.
Statistical is offline   Reply With Quote
Old 27-04-2021, 08:50   #6
Registered User
 
Jammer's Avatar

Join Date: Jan 2010
Location: Minnesota
Boat: Hunter 26
Posts: 2,161
Re: So my boat lacks a lightning ground.

Quote:
Originally Posted by Frankly View Post
You are embarking down a treacherous path (asking that particular question on this forum). You will get a wide variety of opinions.

This topic is on a long and growing list of electrical questions I no longer try to answer.


Quote:

My suggestion (from someone that worked in the LP business for buildings), get a large copper plate (approx, 6 X 24 X 1/4") mounted on the exterior with 4 substantial silicone bronze bolts (say 1/2"), and connect it to the base of the mast with a pair of 1/0 tinned copper battery cables (your choice of insulation color) in the most direct and shortest path avaliable.


I will make the (hopefully uncontroversial) suggestion that tinned copper braid will be far more effective than battery cable.
__________________
Never ascribe to wisdom that which is adequately explained by good luck.
Jammer is offline   Reply With Quote
Old 27-04-2021, 09:26   #7
Registered User
 
OS2Dude's Avatar

Join Date: Nov 2014
Location: Atlanta, GA
Boat: Catalina 30
Posts: 434
Images: 5
Re: So my boat lacks a lightning ground.

I would remove the lightening ground from the electrical system first thing. You are right, if you were to get struck your systems would all be fried and your'e boat likely sink from the lightening trying to get out the shaft.

That said, our boat has no lightening mitigation in place. When we first got our boat, I researched lightening protection quite a bit. Half said it will attract lightening, half said (as above) that it can only mitigate the effects and the last half swore by the latest fad.
OS2Dude is offline   Reply With Quote
Old 27-04-2021, 09:28   #8
Registered User

Join Date: Dec 2013
Posts: 100
Re: So my boat lacks a lightning ground.

One more opinion that is worth what you paid for it. I won't bore you with reasoning. I prefer to isolate the mast and standing rigging from the electrical system. I connect the base of the mast to a large (at least several square feet) grounding plate below the waterline with a short as possible and straight as possible, copper pipe that has been pressed flat at the ends then drilled for a large bolt. Use conductive compound (NOT non-conductive) on the cleaned attachment bolts then seal well with a long lasting sealant. If your bilge is wet paint the bare copper to reduce corrosion.
lvictorlucas is offline   Reply With Quote
Old 27-04-2021, 09:56   #9
Registered User

Join Date: Apr 2005
Location: ME, TCI, On da boat
Boat: Pearson 323, Tayana V42CC
Posts: 787
Images: 1
Re: So my boat lacks a lightning ground.

Do you not have these? http://www.ftp.tognews.com/Projects/.../rudder003.jpg
Some Ty37 owners added ground straps. Look at Projects on the TOG news site
Scubaseas is offline   Reply With Quote
Old 27-04-2021, 09:57   #10
Registered User

Join Date: Mar 2015
Posts: 64
Re: So my boat lacks a lightning ground.

I suspect that 90% of boats have no lightning protection better than a pair of crossed fingers. Wandering around the marina yard I see no grounding plates.
MartinF is offline   Reply With Quote
Old 27-04-2021, 10:08   #11
Registered User

Join Date: Oct 2020
Boat: Coast 34 Sail
Posts: 152
Re: So my boat lacks a lightning ground.

What style keel do you have? Encapsulated keels benefit from adding something external, bolted on iron or lead keels only need protection run to keel bolt. One more thing before the other posts correct my ignorance do not use a sintered bronze ground shoe that is designed for HF radio for your external ground. The sudden charge of a lightning bolt can violently boil\steam the shoe from the inside since it is a honey comb. I realize that lighting and actual instances are unknowable, my favourite example was the ketch at anchor that was struck on the lower mizzen mast aft and then grounded out the anchor chain forward fusing the links.
Tomodore is offline   Reply With Quote
Old 27-04-2021, 10:24   #12
Registered User

Join Date: Jul 2020
Location: Virginia, USA
Boat: Tayana 37
Posts: 151
Re: So my boat lacks a lightning ground.

Quote:
Originally Posted by Tomodore View Post
What style keel do you have? Encapsulated keels benefit from adding something external, bolted on iron or lead keels only need protection run to keel bolt. One more thing before the other posts correct my ignorance do not use a sintered bronze ground shoe that is designed for HF radio for your external ground. The sudden charge of a lightning bolt can violently boil\steam the shoe from the inside since it is a honey comb. I realize that lighting and actual instances are unknowable, my favourite example was the ketch at anchor that was struck on the lower mizzen mast aft and then grounded out the anchor chain forward fusing the links.
it is encapsulated so I will need an external plate. Nigel Calder makes the same warning as you. Looks like the consensus is 1 sq ft solid copper plate as a lightning ground thru bolted and connected to the mast by heavy gauge wire. Should be isolated from the DC system.

It doesn't seem particularly hard (famous last words on a boat) and will give me peace of mind.
Statistical is offline   Reply With Quote
Old 27-04-2021, 10:29   #13
Registered User

Join Date: Jul 2020
Location: Virginia, USA
Boat: Tayana 37
Posts: 151
Re: So my boat lacks a lightning ground.

Quote:
Originally Posted by Scubaseas View Post
Do you not have these? http://www.ftp.tognews.com/Projects/.../rudder003.jpg
Some Ty37 owners added ground straps. Look at Projects on the TOG news site
Thanks for that resource. Not sure how that would connect to mast for lightning ground but will look into it.
Statistical is offline   Reply With Quote
Old 27-04-2021, 10:45   #14
Registered User

Join Date: Mar 2007
Location: Santa Cruz
Boat: Boatless Again
Posts: 5,050
Re: So my boat lacks a lightning ground.

There is a reason a lot of boats don't have lightning grounds. They can create electrolytic corrosion loops.
donradcliffe is offline   Reply With Quote
Old 27-04-2021, 10:56   #15
Registered User

Join Date: Sep 2020
Location: Seabrook, TX
Boat: Catalina 30
Posts: 62
Re: So my boat lacks a lightning ground.

Boat's electrical "bonding" systems will sometimes connect to the prop shaft (bonding the electrical grounds in the boat together to prevent stray voltages).

They utilize electrical brushes on the shaft to maintain contact while the shaft rotates.

Lightning dissipation systems would NOT be connected to the DC system (or the prop shaft). This would be the equivalent of routing a lit dynamite fuse through your powder keg room.

cheers
sinnerman is offline   Reply With Quote
Reply

Tags
boat, lightning

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes Rate This Thread
Rate This Thread:

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Activecaptain on Android Cell lacks much detail Capn Jimbo Marine Electronics 0 25-08-2018 17:10
Prospective boat lacks a few systems jimp1234 Monohull Sailboats 28 08-01-2017 08:53
Mounting Lightning Ground Strip? Beausoleil Electrical: Batteries, Generators & Solar 2 28-09-2012 12:21
DIY Copper Lightning Ground Plate - How Thick ? sv.Crake Construction, Maintenance & Refit 4 13-07-2011 14:46
No Keel Bolts - How to Ground for Lightning ? sabray Construction, Maintenance & Refit 19 25-08-2010 11:12

Advertise Here


All times are GMT -7. The time now is 21:21.


Google+
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2021, vBulletin Solutions, Inc.
Social Knowledge Networks
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2021, vBulletin Solutions, Inc.

ShowCase vBulletin Plugins by Drive Thru Online, Inc.