Does this indicate my transom is good?

[crashkaloop]

Although I thought the Ranger 360v I just bought was a 1989, I just found out it is 1987. This only matters because they stopped using wood in the transom sometime in 1988-89, and this pertains to my question.

While installing a transducer on the bottom of the transom, I noticed that the wood was wet/moist. This got me concerned that I might have a rotten transom. I have read many things on this here, and other forums about this subject, and believe the following:

1) That most older boats with wooden/glass transoms do have moisture.

2) That moisture does not mean the wood is rotted or that the transom is unsafe.

3) That a common way to test the transom is to use the outboard as a lever to see if the transom deflects.

4) Tapping the transom with a hammer will indicate a hollow sound if the wood is bad.

So, after performing number 4 above, and finding all seemed good, I did a very precise test of the transom deflection using the outboard as in number 3 above.

I placed a micrometer on a base in the well just in front the motor. With the motor tilted all the way up, I hung 200 lbs on the cavitation plate. The transom only deflected 35 thousandths of an inch. I could get it to go to 50 thousandths if I bounced the weight up and down. (by the way, the weight was me)

There are no signs of any cracks or anything to indicate the transom isn?t anything but 100% ok, but I wanted to see if my testing bears this out. Can I just do a similar test once in awhile to see when the transom has a problem? Or should I find some way to dry out the wood?

Thanks for any comments.

 

[GWPSR]

Re: Does this indicate my transom is good?

1. Many, not all. Depends on the care of the boat and the conditions it has been subjected to.
2. Yet, but left unchanged, it will.
3. Yes, but not a definitive test
4. Only if it is nearly gone. Many transoms with significant rot have thick enough hulls or enough remaining material (or are tested during the winter...) to produce a solid sound. Without a known hollow section of the same transom, what will you compare what you hear to?

Test drilling at various places in the interior of your transom and stringers is the only way to see what's really going on inside them.

 

[glenn property of pam]

Re: Does this indicate my transom is good?

on the ranger check the top of the transom especially where it changes height. also open the rear and look for cracks in the panel that separates the rear battery area from the rest of the boat. Most old rangers I have seen have cracked due to over sized motors on a weak transom. damp white/yellow wood when you drill a transom that age is kinda expected, Water pouring out of the drill hole and black wood that's mushy is a bad sign.

 

[DAN M VAGOS]

Re: Does this indicate my transom is good?

I have a 89 bayliner Capri and my transom also dose not move when I bounce the motor and I have slightly different sounds in different places on the transom when I tap on it but when I drilled holes to mount the depth gauge and then for the speed sensor the wood was a little moist but looked like new wood and I have used it for 3 years now and it still seems ok. Then again I only have a 50hp on it.

 

[jbcurt00]

Re: Does this indicate my transom is good?

If it's been 3 years Dan, I'd check around those previous test sites & elsewhere. Fully incapsulated wet transom wood isn't 'good to go' IMHO regardless of it's track record of the last 3 years.

 

[GT1000000]

Re: Does this indicate my transom is good?

Core samples are the only sure way to know...
A solid transom has zero deflection.

 

[DAN M VAGOS]

Re: Does this indicate my transom is good?

I see what your saying and I put the transducer in like 3 years ago and wood was better now put in the speed sensor and looks like new moist wood and it was in to different places on the transom but still feels strong and it is 24 years old.

 

[DAN M VAGOS]

Re: Does this indicate my transom is good?

And I did go over the transom with a fine tooth comb and pulled the top cap off the transom and sealed every thing I thought water could get in with. I would recommend any one with a older boat should do.

 

[crashkaloop]

Re: Does this indicate my transom is good?

Dan,
That’s what I wanted to hear. It sounds like you have a very similar situation.

GT,
I guess I don't understand your comment? I can certainly understand how core samples can tell you the condition of the wood, but I see no way that core samples would tell you how much your transom would deflect, or is deflecting.

I also think you are wrong about a solid transom has zero deflection. Any structure will deflect if you apply enough force to it.

I am kind of surprised that my test resulted in only 35 thousandths of an inch deflection? That is with 200 lbs on about a 2’+ moment arm. I can bounce on my motor and you can’t detect any flex at all in the transom with your eyes. That seems to be the proof of a sturdy transom. If you need to use a dial indicator to see the flex, it is very small.

There are no cracks or any other signs of stress, either on the inside or the outside of the transom. So other that getting some moist wood when I drilled, it seems that for now, the transom is rock solid.

But I would like to have the wood dried out so I don't have a problem down the road.

 

[jbcurt00]

Re: Does this indicate my transom is good?

GT made 2 statements not a single 2-part statement.

And how do you propose to have the transom wood dried out so you don't have a problem?

A properly prepped. sealed, maintained transom will last decades. I can't say for sure Dan's won't have several years of service left. BUT he can't be 100% positive that it has 10yrs of service either.

His transom has gotten wet somehow, at this point he probably can't pinpoint where the water intrusion occurred. But since it's encased in fiberglass, 1 area can test good & another 5" away may be a problem.

Your boats, your choice.

Boat & boat resto safely.

 

[crashkaloop]

Re: Does this indicate my transom is good?

Maybe I could have expressed my response to GT a little better.

Taking core samples at the transom would certainly tell me if there were significant problems with the wood in the transom, so that is a good idea if I were thinking about repairing it. But the cost of repair would not be justified on my boat.

My assumptions are that the repair is only required/justified if the transom is showing signs of weakness or failure. The only sign I have that anything is wrong is some moist wood after drilling two small screw holes at the bottom of the transom. This is why I posted the original question about what I would consider a very small deflection of the transom under a pretty heavy load. Maybe I am wrong and 35 thousandths is a big deflection, but to me that is a very small amount.

By the way, the engine is 175 hp.

It seems to me that if a transom is failing or getting weaker, it would show up as deflection of the transom itself. Cracks, deflection, squishiness, etc. would indicate the transom was getting weaker. Can I just monitor the deflection as I use the boat? This test is something I could do everytime I use the boat if I wanted, so the question is “is the deflection as I have described it significant”?

I don't think many transoms have had a catastrophic failure without cracking or showing some signs of weakness prior to the failure. This is baring some accident or other extreme event happening to the boat.

 

[JASinIL2006]

Re: Does this indicate my transom is good?

My transom (see my resto thread) had no deflection but there was substantail rot, enough that I was getting water intrusion in the bilge. Not sure if I was in imminent danger, but certainly I was headed in that direction.

I don't have a lot of faith in the "bounce on the outdrive" test after seeing how much rot was actually there...

Jim

 

[jbcurt00]

Re: Does this indicate my transom is good?

Honestly, for me the deflection isn't a concern. It's the wet wood, encased in fiberglass, so water's gotten in. To what extent, unfortunately, is hard to determine. How long will it take? How bad is it really?

This leads me to: Is today the day?

Accidents happen. What 1 event will be the 1? If it happens, how quick will it happen? When it happens how bad will it be?

Your 200lbs is a lot of force bouncing up & down on an OB lower leg. A 175hp motor probably generates more. How much more?

I spent 20min looking for a 'barely made it back to the ramp' thread. Couldn't find it. Basically a novice had someone help assess the boat, got a green light. Then friends/family pressured them to use the boat as is for now. He posted some info, got basically the same types of respones you did. I think agreed it should be addressed sooner then later, but planned to use it any way. They barely made it back to the ramp when the transom failed. In fact the OB skeg hitting the bottom is what stopped the sinking.........

His boat was likely in much worse shape then yours, but still 'appeared' to be sound. He'd gotten a 'knowledgeable' person's opinion, and it was deemed ok to be used as is................

I don't have a vested interest either way. You asked, & got several points of view.

Jim's resto is 1 of the good 1's. And turned out great..........

 

[GT1000000]

Re: Does this indicate my transom is good?

Morning crashkaloop,

I did mean for my statement to be two separate parts, my bad...sorry.
I still stand by them, though.
You are correct in saying that any supposed immovable object can be deflected if enough force is applied to it, that is the way of physics. As a matter of fact, if nothing ever deflected, our boats would be impossible, as without some deflection they would certainly crack under the stress of the marine environment and sink...
However, under the normal stresses imparted by the engines hanging from the back of our craft, if you can move it even a few thousandths with just your weight on a two foot long fulcrum, how much more is it deflecting while pushing well over a thousand pounds under the stress of the sea...Something that may be hard to measure while underway, unless you can set up the measuring equipment to record all the readings of flex while putting your boat through its paces...
Just look at some online videos of boats jumping up on plane from a stand still...I don't know the numbers, but I would bet that at the moment of incident, there are several tons of force being applied to the transom to make all of that weight literally jump out of the water...
Continued monitoring of your home made stress/ deflection test may, over time reveal the possibility of continued degradation in the structure, but I seriously doubt it would warn you of imminent danger.
That is why core sampling the transom is the only sure way to know the condition of the underlying structure, short of actually tearing into it for replacement purposes.
The fact that the wood is wet is an indication that water is somehow entering the wood and remaining there.
If this is a saltwater boat, you may dodge a bullet in that saltwater is known to prevent wood rot because of its salinity.
However, if it is freshwater and it is allowed to persist and exposed to air, the fungus that causes rot will begin to spread and will continue to spread as long as there is wood left to consume.
Here is a link that has several definitions and descriptions of wood rot, aka; dry rot...
This particular definition explains pretty well what happens in our boats:

McGraw-Hill Boating Encyclopedia: Dry Rot


Top
Home > Library > Cars & Vehicles > Boating Encyclopedia
Finding the fatal fungus, repairing the worst damage
In the days of wooden boats, a diagnosis of dry rot was the news a sailor most dreaded to hear. Dry rot is an invasive fungus that literally eats wooden boats for breakfast?and every other meal, too. It feeds on the fibers of moist wood, turning it into a soft, spongy mass with a telltale musty smell. It spreads persistently in the right conditions, affecting more and more wood until the strength of stress-bearing timbers is totally destroyed. Worse yet, it spreads under a concealing coat of paint, giving little hint of its presence until it?s too late.The name is a misnomer, of course. Dry rot flourishes only in wood with a moisture content of 20 percent or more. It prefers temperatures between 75?F and 85?F (24?C to 30?C) and it needs air, so it will not attack submerged or waterlogged wood.Fresh water is conducive to dry rot, whereas the salt in seawater inhibits it. Fishing boats and other working vessels frequently had rock salt strewn among their timbers for this reason.If you?re buying an old wooden boat, check for dry rot by probing everywhere with a small ice pick or a penknife blade; areas of dry rot offer no resistance. If you?re buying an old fiberglass runabout with a wooden transom or a transom made of wood covered with fiberglass, be wary?this is a notorious place for dry rot.The old way of preventing dry rot was to soak the wood in a good preservative, usually based on copper. Modern methods include sealing the wood all around with a deep-penetrating epoxy resin. The only positive cure is to cut out the affected area and a generous portion of the good wood surrounding it. Less radical measures, such as letting the rot dry and then injecting it with epoxy resin, leave the surrounding wood vulnerable to attack from huge quantities of microscopic spores.Probably the best preventive measure is a good supply of clean fresh air, because air circulation discourages the growth of fungi. Sunlight is an effective deterrent too.
Read more: dry rot: Definition from Answers.com

Hope this helps clear up my statements...
Best of luck and Happy boating
GT1M

 

[crashkaloop]

Re: Does this indicate my transom is good?

Thanks GT. That is a lot of great information.

So, can anyone explain the proper procedure for taking the core samples? Also, I guess that there are a few options based on what a person finds, right?

1) If dry rot is found, transom should be replaced/repaired, or boat might be unsafe, correct?
2) If wet wood is found, what then? Should the transom be replaced/repaired also?

Number 2 is of particular interest to me because I have already found wet/damp wood at the bottom of the transom. What are the options?

 

[GT1000000]

Re: Does this indicate my transom is good?

Core sampling is best done as low as possible on the transom and from the inside...It can be done from the outside, but the cosmetic damage is one most guys would rather not deal with...
Using a 1/4-3/8" drill bit, with a piece of tape on it about an inch to an inch and a quarter wrapped around it as a guide to NOT go deeper...drill into it...
If the shavings come out light and dry, good to go
If they come out dark and wet, not good...
It is not an absolute science and requires a bit of luck, because you could drill into an area that has no moisture or rot in it, but just a couple of inches away from that there could be a section that does...
If you find that everything is good to go, you can just reseal the holes with your choice of 3M 5200, PC-11 Epoxy, Marine-Tex or something like those...

If you find moisture, but no rot, you might be able to dry the wood out over time, using heat lamps or a heat gun. Some have tried these methods with varying degrees of success and failure.

One member is doing this now to his boat and adding ethylene glycol, aka; anti-freeze, to the wood using different forms of injecting it into the wood...here is a link to his thread...http://forums.iboats.com/boat-resto...-suggestions-drying-out-bulkheads-584200.html

 

[crashkaloop]

Re: Does this indicate my transom is good?

I think just one more issue for me to get this process right.

I assume that it would be unlikely for there to be water in the upper part of the transom, without it also being in the lower part. Just gravity. So, Should I take these samples horizontally across the bottom, and work my way up until I have dry wood (if there is any)?

I would guess these holes should be drilled every 5-6" or so across. Is this about right?

Just had one more thought.... would it be a better idea to use a hole saw, of maybe 2" diameter, and just saw through the inner glass skin, and peel that out? I am not afraid of doing the fiberglass patch work, and this would give me a much better feel for what is going on. It also may provide enough area to make drying out the wood possible, if it is not too bad. Of Course, I would drill many few holes overall. What do you think?

 

[Woodonglass]

Re: Does this indicate my transom is good?

200lbs of weight bouncing on th leg with that small amount of deflection indiates to me that you do not have a transom thats in immenent danger of failure. I do agree with all the other remarks about it never being a good idea to ignore a transom core that is wet. You should be making every effort to stop the water intrusion and then monitor the transom closely. I doubt it will ever dry out and will eventually rot and need to be replaced. The actual time frame for this is unknown. JMO!!!!

 

[crashkaloop]

Re: Does this indicate my transom is good?

Woodonglass, I agree, and was thinking most others would agree too. But clearly many are concerned about the transoms wood condition. I am too, but believe that ultimately, it is the strength of the transom that is dictating when a complete failure would occur.

However, I also agree that the condition of the wood will dictate the strength of the transom, and that is why I think everyone is recommending doing the core samples. My only point is that if the boat needs a complete new transom, it would probably not be worth the expense, so I would likely junk the boat.

What would make a great deal of sense to me at this point would be to take a series of 2” or even 4” diameter pieces of the inner skin off of the transom. If dry rot exists and the transom is shot, it’s off to the junk yard. If on the other hand, if the wood is just wet, the large holes might allow it to dry out over the winter (indoors heated), and then I can patch the holes. This would also of coarse mean finding the original source of the leak as well.

Anyway, maybe this could work well, and allow me to keep the boat.

 

[83mulligan]

Re: Does this indicate my transom is good?

Crash, follow the link below. It a thread on my old '73 slickcraft. Jump to page 5 and continue from there. You can see some good pics of core sampling, the removal of the skin, and just how much rot there was in there. You can see where it came from. Mainly, an accident the boat was in and a poor repair job by someone, improper sealing of transducer and other holes drilled in the transom (i'm guilty of some of that cause).

I think everyone here just wants to be sure you don't assume its good and have a bad accident. Water in boats is like cancer. Once its in there it spreads and destroys things. You can't dry it out. You have to make proper repairs if the damage warrants it. I hope you find everything fine and acceptable. Good luck.

http://forums.iboats.com/boat-resto...-slickcraft-trans-string-overhaul-292930.html