Determining Unibond Hull Water Content

A conversation among Whalers
sloanish
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Determining Unibond Hull Water Content

Postby sloanish » Thu Nov 25, 2021 3:39 pm

I have 24 hours to accept or reject the purchase of a 2000 Montauk 17 with a Suzuki DF70 shown below.

Q1: Does this boat seem to be floating on its lines?

staticWaterLine.jpg
Fig. 1. Waterline at static trim.
staticWaterLine.jpg (40.62 KiB) Viewed 3888 times


sternCloseUp.jpg
Fig. 2. Close-up of engine and transom.
sternCloseUp.jpg (38.45 KiB) Viewed 3888 times


sternCloseUp2.jpg
Fig. 3. Close-up of hull drain relative to waterline
sternCloseUp2.jpg (20.33 KiB) Viewed 3888 times


A survey using an Electrophysics GRP33 meter [gave an indication of a undescribed metric of] 25-percent [water].

On-line folks say either avoid or that [an indication of a undescribed metric of 25-percent water] is standard with Whalers.

Most say weight is the real concern.

Thanks

Outrage 20
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Location: Laguna Hills CA

Re: Determining Unibond Hull Water Content

Postby Outrage 20 » Thu Nov 25, 2021 11:43 pm

There was water in the hulls of old 13-footers and 17-footers I owned.

I put the hulls on their trailer in my driveway for a few months in the southern California winter. I drilled holes in the lower stern and let them drip dry(ish) each year. Otherwise they lived in the water for the rest of the year. I had no concerns; this is a standard procedure.

ddqarch
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Re: Determining Unibond Hull Water Content

Postby ddqarch » Fri Nov 26, 2021 9:12 am

I recently purchased a 1985 Montauk 17 and re-powered with a Suzuki DF 90, same weight as a DF70. I bought it with a Yamaha 115 4-stroke on it, and the battery located in the stern, and the splash well drain plugs were well under water. After re-powering and moving the battery under the console, the transom splash well drain holes are both still under water--but just barely.

I have gathered from this forum that old Boston Whaler boats [at their static trim] are just that way [i.e, their transom splashwell drains are underwater].

I have read not to drill holes, as very minimal water will come out that way. I have also read to drill weep holes, and they do help.

I'll be interested to hear other responses to your post. I suspect a number of people will be.

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Phil T
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Re: Determining Unibond Hull Water Content

Postby Phil T » Sun Nov 28, 2021 4:33 pm

The hull is sitting just fine.

Moisture meters are not accurate on Boston Whalers. There are other techniques used to determine water ingress.

The water line below the drains is indicative of a pretty dry aft hull.
1992 Outrage 17
2019 E-TEC 90
2018 LoadRite 18280096VT
Member since 2003

sloanish
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Joined: Wed Nov 24, 2021 7:20 pm

Re: Determining Unibond Hull Water Content

Postby sloanish » Sun Nov 28, 2021 7:36 pm

Thanks everyone for the updates.

Q2: What other techniques [can be] used to determine water ingress?

Q3: Should I bother drilling some holes while the boat is on the hard and covered to dry it out any?

Q4: Where [should holes be drilled]?

I have had some experience with trying to dry out old windsurfer hulls. It just takes time.

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Phil T
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Re: Determining Unibond Hull Water Content

Postby Phil T » Sun Nov 28, 2021 7:50 pm

You are assuming something that may or may NOT be true.

I recommend a new owner inspect all through hulls. If they look worn or old, just replace them. This way you KNOW they are good. Either Sue at Beacon (http://www.beacontcm.com) or Justin at Nauset (http://www.nausetmarine.com) can get you the materials.

I would never drill a hole.

Inspect the hull inside and out and seal any holes with epoxy. Locketite Marine Epoxy in white cures to a complementary color to the hull's desert tan.

Take photos and post the ones that cause you concern and we'll set you straight.
1992 Outrage 17
2019 E-TEC 90
2018 LoadRite 18280096VT
Member since 2003

jimh
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Re: Determining Unibond Hull Water Content

Postby jimh » Mon Nov 29, 2021 8:33 am

sloanish wrote:Q2: What other techniques [can be] used to determine water ingress?
See the answer in the FREQUENTLY ASKED QUESTIONS answers at

Q3: Is There Water in a Hull?
https://continuouswave.com/whaler/reference/FAQ/#Q3

sloanish
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Re: Determining Unibond Hull Water Content

Postby sloanish » Tue Nov 30, 2021 12:14 pm

Many thanks for the advice.

jimh
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Re: Determining Unibond Hull Water Content

Postby jimh » Wed Dec 01, 2021 9:33 am

Regarding the use of a moisture meter to assess the water content in the Unibond hull of a Boston Whaler boat: I don't believe there is any particularly useful or reliable or scientific information about what a particular meter of this type might indicate on a particular Unibond hull. I don't believe there is any calibration standard used across the industry to calibrate these moisture meters.

It is also quite possible that some trace amount of water remains in the interior of a Unibond hull after the liquid reagents have been chemically changed to a foam. Water may be an element in the chemical reaction that produces the foam.

Cf.: https://www.osti.gov/pages/servlets/purl/1369443

jimh
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Re: Determining Unibond Hull Water Content

Postby jimh » Wed Dec 01, 2021 9:43 am

sloanish wrote:Many thanks for the advice.
Did you purchase the boat?

sloanish
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Re: Determining Unibond Hull Water Content

Postby sloanish » Tue Dec 07, 2021 8:04 pm

Yes I did.

jimh
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Re: Determining Unibond Hull Water Content

Postby jimh » Wed Dec 08, 2021 9:18 am

Congratulations on the new boat.