2007 170 Montauk Dark Water Seeping From Through-Hull Fittings

Repair or modification of Boston Whaler boats, their engines, trailers, and gear
Mory
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2007 170 Montauk Dark Water Seeping From Through-Hull Fittings

Postby Mory » Mon May 17, 2021 11:36 pm

My recently acquired 2007 170 Montauk appears to have some water problems. After a mid winter bath, the boat was moved to my garage for detailing and preparation for the upcoming boating season.

A few days after a thorough washing, I noticed a line of dark coffee-colored water running down the transom starting at one of the through hulls. I cleaned it, yet it re appeared a few days later. I assumed I had dislodged some dirt when washing.

Weeks later I notice some dried dark color seepage inside the splash well, again coming from the through hulls. Again I cleaned it, but it re appeared later. The same dark seepage sits inside the recess of the joined through hull outer and inner section that is visible from the splash well.

Also, while working in the boat I noticed clear water in the [cockpit sump] compartment. I dried it, but it's re appeared a number of times. This too appears to be seeping from the through-hull.

This weekend I decided to remove the transducer. Upon removing the screws, and removing the sealant that patched the holes of a prior transducer, a few drops of water came form the mounting holes. I've left the holes open for the past few days and periodically I notice that same coffee colored line of seepage.

This is clearly not good.

I assume at minimum the through hull fittings should be removed for assessment.

Please offer me your thoughts on how to further assess this and my best course of action. Thanks.

Masbama
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Re: 170 Montauk Dark Water Seeping From Through-Hull Fittings

Postby Masbama » Tue May 18, 2021 8:45 am

The dark, coffee colored water you mention is most likely tainted by rotted wood. I had the same exact concern with my 2003 190 Nantucket. I had the whole transom re-done.

Remove the through-hull fittings and see what the wood inside the transom feels like. If it is wet but relatively solid you can try to dry the wood.

roundle1979
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Re: 170 Montauk Dark Water Seeping From Through-Hull Fittings

Postby roundle1979 » Tue May 18, 2021 9:49 am

You might have some water in the transom. Water does not necessarily mean you have a rotten transom but it's certainly going to cause a problem in time.

You might want to have someone with a Moisture Meter examine the transom and areas below the water line.

Do you have any accessories screwed into the bottom area of your transom, like a speed sensor or sonar? If yes, remove the screws and see if you have water pouring out.

As for through-hulls, Boston Whaler suggests that you inspect and re-bed these every couple of years. Also, I'd check the engine mounting bolt holes as well.
2004 Nantucket 190 w/ Mercury Optimax 135

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GoldenDaze
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Re: 170 Montauk Dark Water Seeping From Through-Hull Fittings

Postby GoldenDaze » Tue May 18, 2021 11:06 am

There's a very informative thread on transom through-hulls at https://continuouswave.com/forum/viewtopic.php?f=6&t=2729
2003 160 Dauntless Golden Daze

Mory
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Re: 170 Montauk through hull seepage

Postby Mory » Tue May 18, 2021 9:22 pm

Thanks for the replies and redirecting me to the through-hull thread. Good information and startling at the same time.

The dark stained water that is periodically seeping from the through hulls, and now the transom mounted transducer clearly indicates water intrusion.

I guess the best action is to remove the through-hull fitting and make a further assessment. These appear to be press fit together.

Q1: Where is information about for removal and installation of through-hull fittings?

Masbama
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Re: 170 Montauk Dark Water Seeping From Through-Hull Fittingsage

Postby Masbama » Wed May 19, 2021 7:37 pm

Get a scraper and scrape between the hull and the thru hull fittings then start prying loose. They will eventually pull out.
Let us know what condition you find the transom wood.

roundle1979
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Re: 170 Montauk Dark Water Seeping From Through-Hull Fittings

Postby roundle1979 » Thu May 20, 2021 10:03 am

Mory wrote:Q: Where is information about for removal and installation of through-hull fittings?


Boston Whaler posted an instructional video a few years back.

https://www.youtube.com/watch?v=Zby76eoKO-I

Some through hulls are threaded and some are press fit.

When I replaced the through hull fittings on my 2004 Nantucket 190 I ordered OEM units from Nauset Marine. The larger deck drains were threaded while the smaller engine splash well through hull fittings were press fit. I threw away the OEM plastic press fit units and found brass units from Perko that were threaded.

In addition to the through hulls, water may be coming in through the engine mounting bolts. There are plenty of people who report that no sealant was found in the engine mounting bolt holes when swapping motors.
2004 Nantucket 190 w/ Mercury Optimax 135

Mory
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Re: 170 Montauk Dark Water Seeping From Through-Hull Fittings

Postby Mory » Thu May 20, 2021 6:40 pm

I removed the two engine splash well through-hull fittings. Each came out with minimal effort, and with brown gunk and some moisture.

After wiping away the gunk, the transom material was exposed and seems solid with no moisture damage.

I removed the [cockpit sump drain] through hull fitting [and found the same condition as described above for the engine splash well fittings]. I saw a drip of water, but mostly brown gunk. Again the material beyond the [laminate] is solid and dry.

Were I the one to originally install these fittings,, they would've gone in with more sealant. I'm leaving them open to observe. The sealant around each was minimal, but they seem to solid.

The lowest opening on the transom are the holes left after removal of the transducer which was installed by the prior owner. Again, I would've applied far more sealant. One of those holes seeps some occasional moisture, so I've left them open and will apply heat.

Q2: What else I should pull and reseal?

Q3: Should I remove the lower engine mounting bolts?

Q4: Should I leave well enough alone?

Q5: Should I remove the swim platform lower bolt?

Q6: Should I replace all of the removed through hulls?

Q7: Should I use 3M4200?

Q8: Should I use 3M 5200?

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Phil T
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Re: 170 Montauk Dark Water Seeping From Through-Hull Fittings

Postby Phil T » Thu May 20, 2021 6:53 pm

No need for 4200 or 5200 on your boat.

A marine sealant. Boat Life's Life Caulk

https://www.wholesalemarine.com/marine-sealant-caulk/#
1992 Outrage 17
2019 E-TEC 90
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Masbama
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Re: 170 Montauk through hull seepage

Postby Masbama » Thu May 20, 2021 10:30 pm

Well it seems like [the hull is] going to be okay--and that’s good news.

Make sure those transom holes are dry. Follow the Boston Whaler demonstration and Phil’s advice.

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Re: 2007 170 Montauk Dark Water Seeping From Through-Hull Fittings

Postby jimh » Sat May 22, 2021 6:00 pm

Mory wrote:Q2: What else I should pull and reseal?
Check all fastener holes located below the water line or anywhere where water could puddle and collect to determine if they have been installed with proper care and sealing.

Mory wrote:Q3: Should I remove the lower engine mounting bolts?
The lower engine mounting bolts should be checked. Often if the bolt is removed then the hole itself can be cleaned, then given a coat of epoxy resin to seal the foam and wood. The hole is then re-drilled to restore the proper inside diameter, and the engine mounting bolt reinstalled with proper use of sealant.

Mory wrote:Q4: Should I leave well enough alone?
If there is proper sealing, then the need to remove and reseal is not urgent.

Mory wrote:Q5: Should I remove the swim platform lower bolt?
See Q2's answer; this is a variant on the same question as Q2.

Mory wrote:Q6: Should I replace all of the [already] removed through hull fitting?
Since the boat is a 2007 model year, it could have been made in Summer 2006. The boat could be about 15-years-old. With the fittings already removed, and the cost of new fittings not particularly a burden, ordering and installing new fittings is probably a prudent choice rather than reinstalling the 15-year-old fittings.

Mory wrote:Q7: Should I use 3M4200?
Probably not a good choice.

Mory wrote:Q8: Should I use 3M 5200?
Definitely not a good choice.

I believe the other thread mentioned for your reading has advice regarding sealants.

jimh
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Re: 2007 170 Montauk Dark Water Seeping From Through-Hull Fittings

Postby jimh » Sat May 22, 2021 6:05 pm

The appearance of a dark liquid from the interior of a Boston Whaler Unibond hull that has been in service for many years is not particularly unusual, rare, or indicative of a huge problem. The dark liquid may be a product of some moisture left in the hull at the time of molding the boat reacting with some uncured resin in the hull. When the foam-creating chemicals produce the foam, there is probably some water or water vapor as a by-product of the chemistry. The goal is for all of this to be vented out, but it would not be reasonable to expect that every hull made with every molding process results in absolutely no moisture left in the interior. I have seen dark liquid come out of a fastener hole on an older Boston Whaler boat that had received the absolutely finest possible care over its entire service life. This just happens.

If all the liquid is confined to the transom area with embedded wood, then the dark liquid could be associated with some wood rot.

Q9: Has the boat been used in freshwater or saltwater?

The reason for the question: saltwater does not tend to cause wood rot, but freshwater does.

Mory
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Re: 2007 170 Montauk Dark Water Seeping From Through-Hull Fittings

Postby Mory » Tue May 25, 2021 10:18 pm

The 2007 170 MONTAUK is a saltwater boat. It has spent a good bit of its existence on a boat lift out of the water, and it isn't bottom painted.

The open through-hull fittings are dry. I am keeping an eye on the open transducer mounting holes for additional moisture.

Mory
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Re: 2007 170 Montauk Dark Water Seeping From Through-Hull Fittings

Postby Mory » Wed May 26, 2021 9:34 pm

I ordered new thru hull fittings from from a Boston Whaler dealer. The openings are presently without sealant, and I'm told those should be sealed and dry before installing the new thru hulls with sealant.
Question 1: Which is the proper marine sealant? I've heard 4200, Boat's Life Seal, Boat's Life Caulk. Today, I called Boston Whaler and was told they use Sika flex 291 for thru hulls and below the water line. They use Sikasil n plus above the water line which wouldn't be applicable. Is there a consensus? If not, I'm probably going to use Sika flex 291.
Question 1B: Do I need to clamp the press fit thru hulls while they're drying?
Question 2: I'd like to permanently seal off the transducer holes that were drilled into the transom. I have previously used West System epoxy 101 system. My plan is to use a syringe, inject the epoxy and close the holes. I will probably do two applications to play it safe. I may finish off with gel coat patch paste, or possibly sealant from above since I will be installing a stern saver for re mounting the transducer. Is this a good method and materials?
Thanks

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Phil T
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Re: 2007 170 Montauk Dark Water Seeping From Through-Hull Fittings

Postby Phil T » Wed May 26, 2021 9:49 pm

The factory uses SikaFlex 291 because it has a fast cure.

1 a) I would use Life Seal (not Caulk) as it bonds with plastics.

The hole should be sealed with Life Caulk. Life Seal should go on the transom interior and exterior wall faces.

1b) The two parts of the tube are press fit.

2) Sound plan.
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Mory
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Re: 2007 170 Montauk Dark Water Seeping From Through-Hull Fittings

Postby Mory » Thu May 27, 2021 8:58 pm

Thanks for the advice Phil!