Hot boat issue

[RETIRED JETBOATMAN]

Have a Heavy gauge alum boat, with a newly installed Minn Kota AP V2 70#. I am trying to check for electrical leakage to the hull. #1 I have heard somewhere, that a wire from neg batteries, should be run to back of boat, to neg ground. Cannot get info from the Minn Kota web site for some reason. Correct ?? #2 I know that if I have downriggers on the boat, with wire, and I want to check for HOT BOAT leakage, put it in the water, and test the wires. ?? Can I test the boat ( no DR's) out of water, and get accurate info ??

 

[Grandad]

Re: Alum Hull issue

Re: Alum Hull issue

A conductive aluminum hull as you have surmised could become "hot" from current "leaking" from a failed component or a pinched wire. Is your Minn Kota the only electrical appliance that you have? Assuming that this motor is in addition to a larger motor with an electric start and generator on a powerboat, you probably have at least some lighting circuits. Although there are some who may differ, it's my opinion as a retired electrician that the hull should be intentionally connected ("bonded") to the battery's negative terminal. Doing so removes any possibility that the hull can become "hot". When a positively charged wire or leaking component contacts the hull you have a short circuit. Most times, the short will cause a fuse to blow, assuming that you have fuses in your positive supply from the battery.

Some may argue that minor leakage currents insufficient to cause the fuse to blow can continue flowing for some time and eventually cause corrosion of the aluminum. When you consider that it is almost impossible to prevent the hull from electrically connecting to an engine which is bonded to the negative in it's manufacturing design, it is a fruitless task to try to keep the hull isolated from the negative anyway. Attempts at isolating the hull will only make short circuits less likely to blow fuses when they should and actually make it more likely that you'll have corrosion. As far as testing for a "hot boat", it can be complicated depending on your experience. I would bond to negative and let the fuses do the testing. - Grandad

 

[Thalasso]

Re: Hot boat issue

Have a Heavy gauge alum boat, with a newly installed Minn Kota AP V2 70#. I am trying to check for electrical leakage to the hull. #1 I have heard somewhere, that a wire from neg batteries, should be run to back of boat, to neg ground. Cannot get info from the Minn Kota web site for some reason. Correct ?? #2 I know that if I have downriggers on the boat, with wire, and I want to check for HOT BOAT leakage, put it in the water, and test the wires. ?? Can I test the boat ( no DR's) out of water, and get accurate info ??

What makes you think you have a hot boat leakage?

 

[RETIRED JETBOATMAN]

Re: Hot boat issue

What makes you think you have a hot boat leakage?

More info- The boat is a heavy gauge alum jetboat with V8 engine. Bow mount 70# Minn kota PDAP V2 electric motorw/ charger. Yamaha T8 kicker elect start/power trim at rear.
no other electronics on boat except std running lights. I'm a real experienced steelhead fisherman, but since getting the boat 2 years ago, my catch ratio when fishing bait close to the boat has been lower than normal. When trolling plugs, at 60'-80' behind the boat ok. On other boats with downriggers, I have had the cables tested, and found more than acceptable power leakage to the hull, and had my tech's fix the ground issue to remove it.
Thalasso and Grandad I appreciate your help to check it out!!!!!!

 

[Texasmark]

Re: Hot boat issue

On most leakage problems a "single point chassis ground is the answer". Decide what is the best point of reference and everything goes back there individually (in parallel). You can't have currents through things at the same potential and if all sources of power have a hot and return wire to this single point reference you have eliminated your "source" of leakage current.

Otherwise it could be "static" electricity caused by the boat's movement in the water. If you are saying that you can't catch fish because you feel that your cables are shocking them then I find that a very far fetched conclusion, not being argumentative. And "eddy" currents between any power in your boat and the cables would be conducted through the first few "measures" of your cable and by the time it got to the fish it would be discharged.

Did I get the jest of your question?

Mark

 

[RETIRED JETBOATMAN]

Re: Hot boat issue

Texasmark: The fairly new boat addressed, is a new model, one of 5, I currently own myself. Been boating for 50Years of my 70. Have been in the boating business, both sales, and manufacturing, so thats not the problem. Have done fishing hunting guideing so thats not it.. I have been a Law Enforcement boat trainer, so thats not it.. But what is it, is my lack of technical knowledge on electrical. I am one dumb f*** in that area.
With regard to electrical leakage from accessories, it is and has been a problem in the boating world. That is why they came up with the black box for boats, to decrease and increase in some case the discharge of current. How to test for it on my heavy gauge boats, is what I am looking for. No problem testing on boats with downriggers, but my river jetboats, made to run in 6" of water, don't have them. Until I retired from the Boat Business 5 years ago, I just took the boat to my tech's, and had them check it out, but now I'm trying to test myself.

 

[GA_Boater]

Re: Hot boat issue

Have you tried calling one of your former techs. Might be the easiest way.

 

[Silvertip]

Re: Hot boat issue

If the hull is becoming "hot" (positively charged) as you contend, you would have some blown fuses, tripped breakers, or dead batteries. why?? Because the hull of an aluminum boat is already at ground potential because the very nature of the ground cable connection from the negative battery terminal to the engine block. The engine block is connected by bolts to the outdrive and the outdrive is mechanically connected to the aluminum hull by the attaching bolts. Use an ohm meter to measure resistance from the hull to the negative battery terminal. You shoud show continuity. Therefore any leakage as you call it would represent a short and therefore fuse or breaker issues. First, the troller should be hard wired via the plug/receptacle directly to the troller battery. No need to ground/bond anything to the hull in that regard since that battery is isolated from all other electrical systems. I suspect your boat has an on board charger but that wouldn't provide a hull ground path either. As for the circuits powered by the starting battery, that can't be a source of leakage either for the reasons indicated above. Can you have a short to the hull? Certainly -- but again, something would not be working because shorts blow fueses. If you have different locator(s) in this boat than in the others, that may be a factor but I really doubt electrical leakage is responsible for the low catch. You indicate you had a tech fix an issue like this in another boat. Just what did he fix? Switching type power supplies can be noisy "electrically" so if you have any equipment that uses such a supply try disconnecting it on your next outin(unless it is necessary for navigation or communication).

 

[RETIRED JETBOATMAN]

Re: Hot boat issue

Damn ! Trying this one last time, just wrote a fairly long reply 2 times, only to get it kicked off, and don't know how to retrieve it again. Short version:
Started the search into possible issues, on fri afternoon. A very knowledgeable fisherman suggested "Hot Boat". Having had 3 boat in Ca. that when we checked the downrigger cables, measured (I think) 1.3 volts charge in the wire cables. Reputed to repell fish. As I remember 1 boat (glass) they retrofitted a bonding wire across the transom, the other 2 (one a Tracker)they installed old style black boxes to conteract it (don't know if they did other changes also, don't think the current model Scotty available yet). Minn Kota, Scotty, and a alum Manufactuer were all closed. Doing a Internet search, I came up with lots of possibilities. So I solicited all the experts from the iboat forum for suggestions. One from a great electronics rigger friend in Seattle is to make a makeshift broom stick downrigger boom, and test the cable for charge. Monday with people with the test equip, I will see if we come up with any Boat solution. Hope to find a tech issue with the boat, as the fisherman i had over last week, are way too good to not have hooked more fish.

 

[GA_Boater]

Re: Hot boat issue

Jet, forgive my ignorance, but what is this "old style black box" you refer to. Thanks.

 

[RETIRED JETBOATMAN]

Re: Hot boat issue

Going back about 12 years a guy in sacramento was making a box to adjust the positive charge going into the downrigger cables. It was a std amp/volt meter readout. The new style box is all digital like the Scotty.