Transom on 2007 Marlin

[Meanwhile]

After reading Fishtales adventure with a wet transom I took a closer look at my own Marlin transom. What I saw did not please me but I'm glad that I took the time to inspect.

I found a small crack in the gel coat in the well that ran the entire length of the well. I also noted the jello like substance on my aluminum bangplate. I don't see any bulging of the gel coat on my transom. On installing a new battery charger I noted some rust stains on the inside of the transom from one engine bolt and a wider crack in the gel coat the length of the transom.

So I have arranged an inspection by Schooner Creek in Portland, OR for my transom. Time will tell if I have a small or large issue.

I rented a moisture meter and ran some quick readings on my hull. I'll post a photo of the starboard side reading and the transom reading. This is vudu science to me as I don't have a good feel for the readings. The boat has been in my shop since last November. I've yet to use her this summer.

I'll report back as this progresses.

 

[Fishtales]

good to investigate and jump on it if needed. it will only get worse without proper attention. once you do it, you can spend more money in other areas!

 

[seasick]

That meter is intended for moisture readings for porous construction materials and not for FRP (fiberglass reinforced panel) with gelcoat You will not get meaningful absolute true readings but may be able to detect differences. in general since the hull has been out of the water since last November readings may be misleading and could show little or no moisture since the core may have dried/drained out.
You should measure readings at many spots along the hull, not just the transom and compare. You can not take moisture readings through bottom paint. To take measurements through bottom paint, the paint has to be sanded off in spots to expose the gelcoat.
To get more accurate readings, try reading from the backside (inside) of whatever you can get to.
Note that a rotted hollow core will read perfectly OK.
Ask you surveyor to give you a report of all readings and what make/model meter he or she used.

On a second note, I don't like the look of the separations in photo number 3. The separation could be due to freeze/thaw movement or could indicate a more serious structural issue. Same goes for the stress cracks in the other photos. At a minimum, a good survey and probably removal of the cap and corner moldings to see what is going on.

 

[Harpoon]

you can also compare moisture readings to a newer, known to be dry boat...
photo 3 is odd looking. did somebody add a corner cap
I have a 98 and don't have any of those cracks.

 

[Meanwhile]

Seasick, I tested the hull from bow to transom. I also tested the top before and after each rail, hardware mount or downrigger mount. The only time it showed any red was on the transom. The other readings were in the green.
According to my university, YouTube, bottom paint doesn't alter the readings much. Video showed a surveyor using a meter on different types of bottom paint. I was careful to clean any salt residue off. I'll see what the shipwright says. It is a premier repair facility.

Full Service Boat Repair | Portland, OR | Schooner Creek Boat Works

Schooner Creek Boat Works is a full service boat repair and manufacturing yard in Portland, Oregon. Established in 1977, we are proud to have served the local boating community for 40 years!

www.schoonercreek.com

They have a great reputation here.

 

[Meanwhile]

I crawled into the bilge and tried to get photos from the inside of the transom. You can kind of see the cracks if you zoom in.

I'm looking forward to the inspection on Thursday.

 

[Fishtales]

Could be minor or major. The rust around the bolts is concerning. As you state, get it inspected, find out the data and then you can make a good decision.

 

[Meanwhile]

The boat now sits in a yard waiting for its turn with the shipwright. I'll update the process with photos as I get them.
The estimate is about 12K.

 

[seasick]

Seasick, I tested the hull from bow to transom. I also tested the top before and after each rail, hardware mount or downrigger mount. The only time it showed any red was on the transom. The other readings were in the green.
According to my university, YouTube, bottom paint doesn't alter the readings much. Video showed a surveyor using a meter on different types of bottom paint. I was careful to clean any salt residue off. I'll see what the shipwright says. It is a premier repair facility.

Full Service Boat Repair | Portland, OR | Schooner Creek Boat Works

Schooner Creek Boat Works is a full service boat repair and manufacturing yard in Portland, Oregon. Established in 1977, we are proud to have served the local boating community for 40 years!

www.schoonercreek.com

They have a great reputation here.

I would like to see that video. Was the bottom paint copper based?
I would like to know what meter was used.
The fact that your readings didn't show any moisture on multiple places around the boat except for the transom is not what I would expect. In most cases, lids for anchor lockers, live wells etc, will read higher moisture levels especially because of the way that Grady 'finishes' the edges of the lips
The percentage moisture reading for fiberglass are not the same as other materials like stucco, concrete, wood etc.
15% moisture reading in fiberglass is relatively soaked.
The construction contactless meters read surface moisture which for fiberglass hulls is often nill. The moisture we are concerned about is the core material and to measure that you need a meter that can read deep. Note that some transoms may be 3 or more inches thick. In those areas you can have one dryish side and one soaked side. Your best bet is to measure the hull moisture from the inside as best you can. Of course that means you need a dry bilge and access to the inner sidess..

 

[Meanwhile]

Never drink light beer.

https://www.facebook.com/permalink.php?story_fbid=1078901935837638&id=224010531326787

 

[Meanwhile]

For an older unit that shows the same readings over antifouling paint, start at 30 seconds.

An interesting recent video

Keep in mind I rented a unit for $15 that has limited suitability but did answer my curiosity. What I didn't have is in the photo.

 

[seasick]

Thanks for the link. The presentation was done quite well and made some important statements.
My point about the readings being unreliable over bottom paint according to the presentation may not be 100% accurate but there are a caveats mentioned; First of all, the meters he used are designed specifically with FRP. The meter you used was not and may not give accurate readings.
He stated that if you don't know what bottom paint was used or if the hull was barrier coated, the best approach is to scrape off an area of paint down to the gel coat in order to get accurate readings. My position is that assume the readings through bottom coat may be questionable.
As pointed out, some bottom paints like non copper based may not greatly affect readings, while others will. I was not aware of the fact that graphite in paint will skew the readings. I need to do more research on the issue presented about some paints absorbing a lot of moisture.
His statement that a reading of 92 on the Tramex will be obtained with a moisture content of 3%. I thought the number was higher, like 15% but I guess I was wrong.
The videoe mentions the range settings options on the Trames,1,2 or 3, those ranges relate to how deep the meter is reading , with range 1 being not very deep and therefore reading surface moisture. Likewise range 3 reads deeper. In some cases a range 3 high reading can mean that there is moisture on the back side of the panel being tested ( as may be the case with a wet bilge).
The bottom line is that the skill of the person using the meters is very important. The absolute readings are not nearly as important as comparisons.
Finally, ant decent survey should include mention of the meter model used, a list or sketch of where samples were taken, The weather and the recent history of the boat relating to when last in the water prior to the testing.
I am by no means expert on this topic and never will be. I just don't have enough experience. I just like to research and understand as much as I can about anything that relates to my vessels.

 

[Meanwhile]

A few photos of the work to date.
Info provided by Grady White to the shop to help them understand how the aluminum brace was installed. Shop said the intrusion of salt water showed from the pitting on the aluminum, and the non-structural putty was not adhering to aluminum. No one can explain the rectangular void. I've had the shop check rub rails to be sure, not a problem. Once fabricated with coosa, and lots more glass to fill voids and completely close off the top it will be better than new. The drains from the well will be replaced with fiberglass tubes which in turn are glassed in place.

 

[Meanwhile]

Update on progress. Coosa installed and glass work continues.

 

[Meanwhile]

The work continues.

 

[efx]

I am assuming this boat was kept in the water, correct? The work looks good and that is a LOT of work.

 

[232Grady]

I hope you will share these photos and a copy of the bill with Grady! Everyone can learn from this!

 

[Meanwhile]

Just needs some final fairing done. One more round of primer and than top coat.

 

[Meanwhile]

The shop found some throttle cable issues when putting my engines back on. Better them crawling around than me. Told them to replace all my cables.

 

[Angler Management]

Man... this is NOT what I needed to see after just replacing my engines. I know this has been an issue... I've been ignoring it.

Sigh. OK I'll get someone to look at it next fall. Thanks for the post!