Cored Hull?

In need of advice. Ran across a boat for sale I like. After investigating found out it has leaks that got into the cored hull above the waterline. This info came from people in the harbor. I really like the boat and need some advice on how big of a problem this may be. Could I find and stop the leaks and repair the damage? Or is a cored hull boat just not worth the trouble. Don't need to get in the weeds with a lot of details, just some opinions on leaking cored hulls.

Thanks

A couple recent threads on this topic have a lot of information.

You said the leaks are above the waterline in the core. Is the hull cored below the waterline also. If so this can be a huge can of worms. The water may have traveled all over the bottom or may just be in a small area. No way to tell without hauling the boat and using a moisture meter to find out. Even then will there be more areas that eventually start to leak? There was a long thread in the last two weeks about cored bottoms. Personally I am very glad my hull is solid.

Almost all production trawlers are built with cored decks and superstructure and some are built with coring below the water line.


Water getting into the core at the deck level is often due to stanchions that have been pushed against hard and broke the top layer of the glass that they are attached to or similar damage to the top layer of the glass. This lets water seep into the cracks and wet the core. Another common cause is older teak decks where the screws leak into the core.



A surveyor can tell approximately how bad and extensive it is by tapping on the hull and the use of a moisture meter. If it is minor then rebedding the stanchion can stop it spreading and causing more damage inside. If it is more extensive then you have to remove the top (or sometimes bottom) layer of glass, dig out the mushy core, replace the core and glass over it.


The only time I actually saw this done was to an area of the side decks of about three square feet and it cost several thousand dollars, but looked as good as new afterwards.


But for many older TT trawlers it isn't worth fixing particularly if the rotted core is extensive and in several areas. Rotted core rarely becomes a structural issue.


David

From the info I've gotten it has a solid bottom and only cored above the waterline.

You need an expert to help you understand the extent of the moisture intrusion and the estimated cost of repair. Only then can you make an informed decision. I would guess if others in the marina know it has issues then they are significant issues.

What type of core material?

Dixie Life said:

In need of advice. Ran across a boat for sale I like. After investigating found out it has leaks that got into the cored hull above the waterline. This info came from people in the harbor. I really like the boat and need some advice on how big of a problem this may be. Could I find and stop the leaks and repair the damage? Or is a cored hull boat just not worth the trouble. Don't need to get in the weeds with a lot of details, just some opinions on leaking cored hulls.

Thanks

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It depends on the type of core material. If the wet core is balsa wood, just walk away. Wet balsa dissolves and turns into mush. However, if the core material is CORECELL or a similar material that does not absorb water, it is possible to vacuum out the water and repair the site of the leak. The screws that attach seats and other hardware are a common source of leaks into a cored hull. The cost of these repairs can easily exceed the value of the vessel. Good luck.

Take a look at this recent thread I began:http://www.trawlerforum.com/forums/s3/cored-hull-underwater-42641.html
I thought about this, a lot,and decided against a cored hull underwater. As to a cored hull above water, be the core foam or worse, balsa or other wood product, if it is already wet I would not buy it,if dry I might. To do so with it already wet would be buying into problems,don`t do it.

If the water is in the hull, I would oass. If the water is in the deck it might be a deal if the price is right. Repairing a deck core isn’t that big a deal.

For what it's worth, my cored hull was wet, very wet in 2015, due to a poorly repaired thru hull fitting.
My bashing a couple rocks in Finland, did not help.
In October 2015, pulled the boat and let it dry in windy, wet Ireland.
It took 4 months.
Did bottom job spring 2016.
Cruised from Ireland to Mexico Pacific.
Fall 2018 hauled for winter and they put a small hole in skeg in doing so.
It was dry.

A boat is a complex system. Everything has advantages and disadvantages.
There is no perfect boat, just like there is no perfect hull.

Wxx3 said:

For what it's worth, my cored hull was wet, very wet in 2015, due to a poorly repaired thru hull fitting.
My bashing a couple rocks in Finland, did not help.
In October 2015, pulled the boat and let it dry in windy, wet Ireland.
It took 4 months.
Did bottom job spring 2016.
Cruised from Ireland to Mexico Pacific.
Fall 2018 hauled for winter and they put a small hole in skeg in doing so.
It was dry.

A boat is a complex system. Everything has advantages and disadvantages.
There is no perfect boat, just like there is no perfect hull.

Click to expand...

Wow, KK's have cored hulls below the WL? I never would have guessed that.

South of Heaven said:

Wow, KK's have cored hulls below the WL? I never would have guessed that.

Click to expand...

~1993 is when Krogen switched to solid fiberglass below the waterline from PVC foam core for the KK42.

Anyone have any info on the specs of a Sea Ranger hull? I can’t find anything or if the company is still in business.

Powerboat Guide lists a 46 Sundeck and a 52 Cockpit MY which is the 46 with a cockpit. Built from 1985 to 1989. In my opinion a downside is listed with Volvo engines. 46’ specs were 15’4” beam, 4’ draft, 40k pounds weight, fuel 850 gal, water 350 gal, waste 45 gal, headroom 6’5”. No manufacturers info listed, doubt it is still in business. Said it was heavily built and fit and finish above average.

Should you decide to purchase the vessel be sure to locate a yard that has experience in this type of repair FIRST.

Only they can give an estimate of repair costs , the average marina / boat yard will have no clue!

South of Heaven said:

Wow, KK's have cored hulls below the WL? I never would have guessed that.

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Luckily for me.
Otherwise Dauntless would be at the bottom of the Baltic.

cored hulls below the waterline

We have owned and travelled extensively on a 58 Westbay Sonship over the last 5 years. The Westbays are cored with a divinicell type material and the layup is done with vacuum bagging. I have replaced 2 thru hulls over that time for our generators and where each thru hull was placed there is a west epoxied pillow block glassed into the layup. It looked like the isothalmic resin and glass layup on either side of the coring was about 3/8" thick. We have bashed our way back up to California from Puerto Vallarta in some really crappy weather. Short interval and a lot of pounding hour after hour. Last haulout in June not a crack anywhere.No water intrusion anywhere while doing engine and lazarette checks every few hours. So obviously it comes down to how the cored hull was built. A blanket statement saying this type of hull is no good is a very generalized statement. This boat is 17 yrs. old and we have put about 14K nautical miles on her.

I don’t think that cored hulls are necessarily bad, but they do allow for problems more than a solid hull. Cored hulls have to not only be built correctly but also have to be maintained correctly and there in lies the problems. How do you know how a PO installed through hulls, etc. It is a big unknown.

The answer to your question is we bought the boat from the original owner who had Westbay build it to his specs. All of the thru hulls are original factory installs. The boat was delivered to him with an extensive schematic manual that covers all wiring, plumbing, mechanical schematics. There are 7 thru hulls in the boat installed at the factory plus 2 factory installed depth/fish finders. So the only newly added thru hulls were by me at the yard last June before departing for Mexico.

Yes, Westbay has made some nice vessels over the years. Along with other PNW built vessels such as Pacific Mariner and Westport, their core below the waterline build standards have apparently held up well.

The recent TF discussions are largely regarding known problems with specific problem brands, failing cored hulls, poor maintenance and improper through hulls. But being the internet, lots of chatter gets generated.

Dixie Life said:

In need of advice. Ran across a boat for sale I like. After investigating found out it has leaks that got into the cored hull above the waterline. This info came from people in the harbor. I really like the boat and need some advice on how big of a problem this may be. Could I find and stop the leaks and repair the damage? Or is a cored hull boat just not worth the trouble. Don't need to get in the weeds with a lot of details, just some opinions on leaking cored hulls.

Thanks

Click to expand...

Cored decks, cabin and hull above the WL are very common, essentially most FRP vessels are built this way. Many lighter planing vessels also core below the WL. The latter is by no means a deal killer, but buyers need to be wary of potential water intrusion, which can occur in any of these locations, and especially below the WL for obvious reasons, water is entering the core under pressure rather than simply leaking in (it can also enter from the bilges). In many cases water intrusion is the result of after market installations, antennas on deck, transducers below the WL (several years ago I encountered a 26 foot planing vessel, 4 years old, wherein virtually the entire bottom was "wet", the result of an improperly installed transducer on the transom, making the vessel all but un-sellable)

Under no circumstances should caulk be the sole barrier between water and core. Caulk's life is finite and when it fails you have no way of knowing, so a water path to core that relies on caulk is only a delayed certainty for wet core. All core penetrations, above and below the WL, should be properly and permanently closed out.

Also, many surveyors do not use moisture meters because they do not trust the results, and that's a good thing. Moisture meters should only be used by those who know how to use them and are able to interpret the results. For instance, a moisture meter will read a block of ice as dry, and a sheet of metal as wet. I carry two with me on every FRP vessel inspection. More on moisture meters here https://stevedmarineconsulting.com/photo-essay-cored-composite-construction/

This article delves into the subject of cored composite construction in detail https://stevedmarineconsulting.com/cored-composite-deck-hardware/

The subject is also covers moisture meters and wet core starting on page 109 http://stevedmarineconsulting.com/w...03/Surveyors-Selecting-and-Working-With-1.pdf

Here's one cored hull vessel I wouldn't kick out of bed:

https://www.devlinboat.com/wordpress1/2016/03/sockeye-42/

https://www.yachtworld.com/boats/2000/Devlin-Sockeye-42'-Trawler-2722005/

". Caulk's life is finite and when it fails you have no way of knowing, so a water path to core that relies on caulk is only a delayed certainty for wet core."

These words of wisdom should be painted near the control position of almost every boat built.

Too many folks do not realize replacing calk is required PM , much ungood to wait till the deck rots and water pours into your bunk.