SailNet Community banner
  • SailNet is a forum community dedicated to Sailing enthusiasts. Come join the discussion about sailing, modifications, classifieds, troubleshooting, repairs, reviews, maintenance, and more!

Even with a good survey, there are many unseen horrors

6K views 34 replies 14 participants last post by  hellosailor 
#1 · (Edited)
This season I'm updating my shore power (added a SmartPlug, ELCI, and galvanic isolator) and much of the DC system. The AC side is nearly finished without too much trauma. However, now I've moved on to the DC side and today I discovered one MAJOR issue and a minor issue.

The major issue is shown in the third photo. I removed the negative cables that are attached to the engine to find that the bolt that was originally threaded into the frame of the Yanmar, was nearly completely stripped. It appeared tight, but only a light turn with the wench revealed that it was barely holding the negative cable to the engine. Not to mention all the corrosion and gunk on the metal frame. I'm interpreting this as having dodged a potential bullet. My guess is that this would have eventually failed, maybe even this season and upon failure, could have caused significant damage.

Any suggestions on how best to remedy this problem? What I'm thinking about doing is to clean off all the corrosion and then through bolt the cables (with a lock washer of course) rather than try to drill it out and cut new threads in the casting. Does that sound reasonable?

The minor issue is shown in the other two photos. I'm guessing here, but this doesn't look like the proper way to connect the two smaller wires. I don't know whether this is acceptable under current or past ABYC. Can anyone tell me? My current plan is that the smaller wires will be attached using their own lug.

I guess the moral of the story is that no matter how good the survey (and I believe that my surveyor did a very good job), there are always unseen issues, sometimes very big issues. I'm very glad that I've been slowly going through all the systems, not only to familiarize myself with them, but to correct any inadequacies.
 

Attachments

See less See more
3
#2 ·
Yes, even a good surveyor will not catch everything. The stripped ground bolt on the engine is a good example as it looks fine. However the small wires taped to the battery cable should have been picked up. If there's only a couple smaller wires, just put lugs on them. If more, then you need a bus.
 
#8 ·
Not as a apologist for the surveyor, however, that wire is on the back of an old Perko two battery switch and is otherwise not visible. So my guess is that removing a battery switch is beyond the scope of a survey. My guess is that it was probably done at the factory, but I don't know that for sure.
 
#4 ·
Hey,

Seems like you have things under control.

As you wrote, the surveyor can't find everything. For a prepurchase inspection any testing must be non-desctuctive or visual in nature only. Imagine if the surveyor put a wrench on the ground bolt and it broke? Now I think YOU could be liable for the repair. Same thing with sounding the hull or rudder. Tapping with a mallet is OK, drilling holes is not.

Good luck,
Barry
 
#5 ·
It looks to me like the two smaller wires are crimped under properly in automotive I would be happy with that,possibly some shrink tubing or shrink tape to seal it...connectors crimped on and put under the bolt (although easier to take apart seperatly if necessary)is just more problem connections under the ground bolt,....I would tap it out,put a proper bolt in ,but also put a lock nut behind...after cleaning well and coating with terminal gel as Krisscross said......Ralph
 
#6 ·
I think I would set up a nice ground bus bar. You can have a single wire going from the ground point on the engine, and take the other grounds from there. Make sure you have several unused posts so you can add things later without having to stack. It will tidy that up quite a bit. You should be able to use a through bolt and lock washer. Do things right, so it is easier to do PD work in the future.
 
#12 ·
Thanks. I'm actually going into my second full season, but still very much a neophyte with regard to all the systems on the boat.

I agree, even though it could have caused a major problem, the repair is relatively cheap and easy. -- I do wonder how in the world this was actually done. I don't think it was done by the PO (what owner would have made a connection this bad?). The yard that she was at before I bought her is well respected. But nonetheless, whoever did the previous repair must have known it was stripped. --
 
#13 ·
If you're going to move the ground connection to a new spot, the best place is one of the starter bolts if you can do it. Puts the voltage right where you need it with less resistance. You're not relying on the starter's connection to the engine to transfer the power. That can gunk up and add resistance. Usually the worst that can happen with a bad ground is the engine won't start, but in an emergency I guess we could call that major.
 
#16 ·
Actually your house battery's ground should be seperate,I think,and I assume your running light are run off them.. And yes older ,none computer run,mechanical diesels will run once started..actually if it's a battery problem any engine with a alternator/generator will run once started,also your idea of a boost battery may have worked if you had put ground straight to the engine and not tried to boost the battery as that would have been fruitless with a bad ground!......a good way to check for a bad ground ,is run a booster cable from starter battery to block creating a new ground.......Ralph
 
#19 ·
elliowb,

My battery selector switch on Irish Eyes is mounted directly on the plywood below the companionway, not on a separate piece of plywood screwed over a large opening. Perhaps someone has modified your original installation. All the wiring on the back of my switch are one ring fitting to the wire. Nothing is doubled up.


My engine ground connection is on the aft port corner of my engine (Yanmar 3HM35F) near the tachometer sender. Both the battery negative and bonding grounds are connected to a bolt in the engine block adjacent to the starter motor mount. (I previously had a second battery negative cable going to the alternator frame, but the new alternator I installed this year does not have a suitable bolt. So, until I figure out how to work around that, I have left the cable off.)


I have had a bad engine ground. When Mac Boring rebuilt my engine they repainted it. When the engine was reinstalled in the boat, the paint partially insulated the metal under the bolt and the underside of the bolt head. Until I found the paint, I had problems with the starter motor, the oil pressure gauge, the engine temperature gauge, and the alternator regulator. I never had the opportunity to test the oil pressure and engine temperature switches, but I'd bet they had problems as well. Scraping away the paint fixed all the problems.

Bill Murdoch
1988 PSC 34
Irish Eyes
 
#20 ·
Thanks for the great info and the photos Bill. The original battery switch is the same Perko switch that you have on Irish Eyes. I made the cutout so that I could more easily access the cables and I'm going to install a BlueSeas on/off/emergency switch. It is very possible that someone has altered the wiring prior to my purchase (especially since the ground on the engine has clearly been altered).

The second photo of the aft port side of your engine is helpful. The 3/8th hole that is in the support that runs athwartships, a bit inboard from the engine mount, just aft of the location that your ground is attached is where my ground was attached. Since the threads were very thoroughly stripped, I drilled a new hole in the same support, just inboard of the original hole and threaded it. Tomorrow I'm going to install a bus bar on the port wall of the engine compartment. I think that should solve that part of the problem that I encountered.

After removing the cable from my start battery, I discovered even more reason for why I'm happy that I am replacing some important elements in the DC system. The better part of the lug has been eaten away, due to the stripped ground bolt.

-- Bill Elliott

Belle Voile
 

Attachments

#21 ·
As you are re-newing your primary DC circuitry You may as well do it correctly. Sage advise at Mainesail's site.

I.e. Dimple crimps are not really all that reliable in the long term. Good luck. I have replaced all my wiring on what I refer to as the primary DC circuitry. (Everything up to the distribution panel.)
 
#23 ·
As you are re-newing your primary DC circuitry You may as well do it correctly. Sage advise at Mainesail's site.

I.e. Dimple crimps are not really all that reliable in the long term. Good luck. I have replaced all my wiring on what I refer to as the primary DC circuitry. (Everything up to the distribution panel.)
I'm relying heavily on the information that MaineSail so graciously posts on forums as well as his website. I've also tried to give back to him a bit by purchasing items from him (for example I have replaced my ancient battery charger with the Sterling Ultra with remote and I'm using the Balmar Smartgauge to monitor SOC).

MaineSail's information is INVALUABLE!

To your point about dimple crimps, that was what I found when I removed the heat shrink. I have the FTZ crimping tool and will be replacing many of those with tin-plated power lugs.

Another inadequacy I've found, none of the connections to any of my batteries had fuses. None whatsoever! I guess that may have been acceptable back in 1994 when my boat was built. That will be corrected before she splashes this spring.
 
#24 ·
Dimple crimps, interesting term. I've only heard them call "staking" or "stakes", i.e. you drive a stake into the crimp sleeve to compress whatever is in it. Crude but effective, just not as good as a proper solid crimping job.

I'm not a machinist, but suspect that if you run a drill bit through that grounding hole, smooth it out, you will find it easier to retap the hole afterwards. Retapping and adding a nut and star washers should give you a really solid ground. Dressing the bolt with a little antiseize will also ensure there is no corrosion forming there afterwards.

"Master" ground points at the aft corner of the engine can be fun. After a gut rewire and some other work on a boat about fifteen years ago, we weren't getting good power and happened to notice, almost incidentally, that one of the few original cables left was the master ground...which was making huge sparks in the darkness "way back there". Same thing, one bolt in a place no one normally sees or goes.
 
#25 ·
Mine might have been sparking a bit occasionally (I hadn't looked back there while under way). Luckily I laid a wrench on the bolt and discovered the problem before it got worse. I'm also fortunate that on the PSCs, the cockpit floor lifts out for much easier (although still quite tight for a 5'10" 185# adult) access to the back of the engine.

The new attachment for the ground is threaded with a lock washer and a nut and lock washer on the other side just for good measure.
 

Attachments

#26 · (Edited)
It's interesting. Your battery negative is connected to the rear engine mount plate. I have the hole in my rear engine mount plate just like yours, but my battery negative is connected to the bolt on the engine near the starter motor. Capt jgwinks suggested attaching the battery negative to one of the starter motor bolts. That is three different ideas. That got me thinking (and it is raining in Blackpoint in the Bahamas right now), so I looked in the Yanmar Service Manual. This is the illustration on page 12-1. It seems capt jgwinks and the Yanmar manual are in agreement.



Bill Murdoch
1988 PSC 34
Irish Eyes
 
#27 ·
Thanks again. I've already got mine reinstalled, and given that it had been working fine, I think I'll leave it. At least for the moment.

This entire upgrade process is so painstakingly slow anyway. Today, I finally got my new charger completely installed and wired, and all wires are led to their appropriate places. I'm hoping that by the end of the week, I'll be close to completely finished with the DC upgrade.

-- Bill
Belle Voile
PSC 34
 

Attachments

#30 ·
Someone asked what could happen if the ground falls off other than the engine not start or the lights don't work.

I'm pretty sure there is a risk of sparks which means there is a risk of fire.
 
  • Like
Reactions: elliowb
#34 ·
I agree a loose positive is always more dangerousness which is why you always take off the neg first(the tools don't spark if you touch wrong part) ,but also there is always other smaller ground(smaller gauge)hooked up here and there,these can be a problem as if there is a large current draw ,such as a starter trying to get thru them they will heat up red hot( like a heat element hot)possibly starting plastic,wood or?? On fire.....ask me how I know this..!!..it's no fun replacing all the wiring for beacons,clearence lights ect...just cause of a bad main ground...Ralph
 
#35 ·
Note that the Yanmar wiring diagram was drawn before battery primary fuses were invented. A retrofit might include that now, so even if a cable shorts out someplace, a primary fuse might blow before anything caught fire. And it is possible that the alternator output wire is still a fusible link wire, which was considered a safety factor then but is considered a fire hazard now.

If you are concerned about "if it comes loose it could short out" situations, a piece of neoprene foam (wetsuit material) or heavy plastic (clear vinyl by the roll, or place mats) or even the new "peel-able auto vinyl paints, can make a good simple addition, ensuring that a simple short won't happen. Cheap insurance.
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top