Cored Hull Underwater

[BruceK]

Apologies for not posting the video earlier,and confusing some of the build procedures.
Does the video add to anyone`s understanding and opinion?
I`m holding off making an offer, I could go lower than I planned, but the kernel question is, do I want to own it, at all? Which is what this thread will help me resolve.

[Insequent]

Bruce, you seem quite keen on this one, and I can understand why. I'll do some thinking out loud as it were, in case it might help you.

The video does not really help. Although, it refers to the balsa being encapsulated, which IS NOT saturated or sealed. Any delamination of balsa from the fibreglass (either side) will provide a pathway for water. Once water is in, it cannot be removed, you cannot dry out wet balsa. You have to cut it out, re-core and replace the 'glass skin. In theory stress flexing could delaminate the balsa. How well your surveyor will be able to test for delamination or sections of wet balsa, I don't know. That is the cautious angle.

Beneteau have been in business a long time, and have built many boats. There does not appear to be many core failures, or it would be readily found by searches and on forums. Maybe their designs manage the stress regime well, and their resins and manufacturing methods ensure very good bonds to the balsa. As others have noted, balsa used in boat building when this boat was built, as opposed to the 1980's Taiwan learning period, can be perfectly fine. More than likely Beneteau did it well, but surveying to look for delamination would be prudent. The hammer test by an experienced person I guess. This is the 'trust the brand' angle.

Ideally I would want to remove underwater through hulls to inspect for correct fitting (oversized holes with thickened epoxy etc) but in particular search for any non-standard, potential DIY fitting work, topsides as well as below the water line and check those carefully. Including the portlights you mentioned. Moisture meter at minimum if removal is not feasible pre-purchase. Factory-fitted penetrations might all be fine, later DIY ones might not be. You might only be able to do this after your offer, subject to no material adverse survey results, has been accepted. I'd make it clear that any areas found defective will result in the offer being lowered, but clearly it would have to be a material issue highlighted by the surveyor that could take real money to fix.

[bogranjac1]

Originally Posted by BruceK

Apologies for not posting the video earlier,and confusing some of the build procedures.
Does the video add to anyone`s understanding and opinion?
I`m holding off making an offer, I could go lower than I planned, but the kernel question is, do I want to own it, at all? Which is what this thread will help me resolve.

.

Hi Bruce,
I have read your numerous posts over this boat,starting from the hull blisters noticed around the transom to yesterdays post.
You seem very wary and ill at ease over this boat !!
Walk away from this boat or you will never feel relaxed and always be thinking of some negative. Your spending huge money here. Go find another fish from the ocean.
Regards to you both.
Brett

[North Baltic sea]

Hi,


I have checked the single ST42 purchase intention, but the hull sides very much liike a spider network (stress cracks) and the risk of water to move kapilar in the core.


I didn't look at the other ST42, so whether this individual had experienced a hard or type of failure?


NBs

[FF]

QUESTION: Why does a "state of the art" boat get blisters?

Which era of "state of the art?"

Cheap resin choice ,thinned too far for quick wet out , poor workmanship , dirty work area poor layup schedule ,to name a few.

THe use of balsa instead of foam that will not get saturated with water is done purely foe economic reasons.

Price AIREX , one of the best core materials to see price of quality. .

[bayview]

People forget that water can enter a cored hull from inside as well. Anything screwed into the inside of the hull is cause for concern.

There are many cored hulls afloat that seem OK but I don't need another thing to keep me awake at night.

[bayview]

There once was a KK type( I don't know the actual brand) trawler in a yard near me that was having the entire bottom replaced because of balsa core rot.


I would not own balsa cored hull. Synthetic cores however are fine IMO. I also did the experiment of soaking synthetic core samples for many months without any apparent change or damage.

[Ka_sea_ta]

I think that the early adapters of coring below the waterline experienced a learning curve. 90's era Sea Rays were a horror story. weirdly enough Bayliners and many other builders cored their hulls below the waterline without issues if proper precautions were used when installing hull penetrations ... From a design perspective the weight reduction is needed to achieve performance at a reasonable cost.. The building techniques have improved... If this is "the boat for you" and the survey is good, a cored hull would not be a show stopper for me

[Haylands]

I think if you have to ask on here if you should buy a particular boat because of its construction technique then you have answered your own question....

If in doubt move on...

Good luck in the search, we found it fun....

[bayview]

I don't think that using balsa today when synthetics are available is defensible.

[Codger2]

Originally Posted by BruceK

I`m holding off making an offer, I could go lower than I planned, but the kernel question is, do I want to own it, at all? Which is what this thread will help me resolve.

Bruce, I've followed your frequent posts for about 7 years (Over 9000) & can't believe you are considering buying a boat that has a completely balsa cored hull! You must be lusting over this vessel to ignore all the wisdom you've displayed over the years. Don't do it! You'll always regret it when it comes time to sell!

[Codger2]

Originally Posted by Haylands

I think if you have to ask on here if you should buy a particular boat because of its construction technique then you have answered your own question....

That sums up my feelings on the matter.

[Ka_sea_ta]

Originally Posted by Codger2

Bruce, I've followed your frequent posts for about 7 years (Over 9000) & can't believe you are considering buying a boat that has a completely balsa cored hull! You must be lusting over this vessel to ignore all the wisdom you've displayed over the years. Don't do it! You'll always regret it when it comes time to sell!

Hull design and deck structure

Ocean Alexander has continued to perfect and refine the hull of their yachts to help improve on performance, efficiency and balance. The Ocean Alexander 90 features crash bulkheads and hull stringers which are engineered to offer structural soundness and hydrodynamic stability. The hull is composed of a closed-cell foam core from deck to waterline. The underlying hull below the waterline is an end-grain balsa-cored superstructure. Unidirectional carbon fiber provides extra strength to reinforce the bulkheads and stringers.


seems strange you're so vehemently against coring
just sayin

[DavidM]

I guess I have a different take on the value of this boat as I am not too concerned about the balsa coring below the waterline. Looking on Yachtworld, there are 4-5 Swift Trawler 42s listed in the US in ranging from US$200,000 to $275,000. Your boat has two known problems: water leaking around portlights and possibly the ceiling and a poorly designed exhaust system (shared with me by PM).

The former issues may be somewhat expensive to fix, particularly fixing the cosmetic results inside. The exhaust system problems can be managed with extra maintenance.

So put those two issues (the exhaust should be common to all ST42s but few will know it is a problem) against the US boats, figure on 10% less than asking for actual sales prices and add whatever premium that Australian boats command over US boats and see if it is competitively priced.

Then if it is, make an offer at about 10% below what you want to pay to compensate for these risks and see what happens.

David

[DDW]

There is no such thing as "saturated" balsa core, even if infused. Also, even foam cored boats can get wet inside, the scoring that allows the foam to conform provides hundreds of water channels to allow water to run where it wants. Foam will not rot, but some kinds get pretty soft after a decade of being wet.

A cored boat requires attention to detail not usually found in a production builder. Every hull penetration should have the core rebated back and solid glass in its place. There should be no screw penetrations through the outer OR inner skin. It takes a determined custom builder to achieve that.

[sunchaser]

Originally Posted by Ka_sea_ta

Hull design and deck structure

Ocean Alexander has continued to perfect and refine the hull of their yachts to help improve on performance, efficiency and balance. The Ocean Alexander 90 features crash bulkheads and hull stringers which are engineered to offer structural soundness and hydrodynamic stability. The hull is composed of a closed-cell foam core from deck to waterline. The underlying hull below the waterline is an end-grain balsa-cored superstructure. Unidirectional carbon fiber provides extra strength to reinforce the bulkheads and stringers.


seems strange you're so vehemently against coring
just sayin

Comparing a spanking new multi million dollar yacht to a 17 year old Swift Trawler is not easily done, except for argument's sake.

Two very different boats, two different builders, two different build techniques, two different QA/QC protocols and two different eras - a huge difference.

[ancora]

One of our club members had an Offshore 55 footer who got "center punched." By the time he got the boat back into his slip, the balsa coring was saturated. The whole side of the vessel had to be stripped to remove the soggy balsa wood at great cost to the insurer.

[Ka_sea_ta]

Originally Posted by sunchaser

Comparing a spanking new multi million dollar yacht to a 17 year old Swift Trawler is not easily done, except for argument's sake.

Two very different boats, two different builders, two different build techniques, two different QA/QC protocols and two different eras - a huge difference.

You are exactly right, that's why a blanket statement about in this case. "balsa coring below the waterline" is typically not accurate. As far as the ST goes the salon and galley layout on the ones we on weren't my cup of tea. But I've haven't heard or read anything about water intrusion issues in the hull either.

[sunchaser]

Originally Posted by Ka_sea_ta

You are exactly right, that's why a blanket statement about in this case. "balsa coring below the waterline" is typically not accurate. As far as the ST goes the salon and galley layout on the ones we on weren't my cup of tea. But I've haven't heard or read anything about water intrusion issues in the hull either.

You miss one critical element in your argument. Beneteau and other builders of small recreational vessels do not always put the time, money, effort and research into building the best composite hulls. I know what Westport has done for 20 years, building excellent composite hulls. Hopefully the big OAs are even better.

All sorts of planing composite hulls on the market, especially in the size and weight range where lifting them out of the water is common. This is a great application, normally.

If you're buying or building a smaller "glass" in the water all the time yacht, stick with the herd in avoiding any chance of hull saturation - go solid FRP and do it well - makes sense to me.

[BruceK]

Originally Posted by bogranjac1

.

Hi Bruce,
I have read your numerous posts over this boat,starting from the hull blisters noticed around the transom to yesterdays post.
You seem very wary and ill at ease over this boat !!
Walk away from this boat or you will never feel relaxed and always be thinking of some negative. Your spending huge money here. Go find another fish from the ocean.
Regards to you both.
Brett

Thanks Brett but there are 2 boats, a Pacific 40 in Cairns, and this Beneteau in Sydney. So far the Beneteau hasn`t revealed any osmosis, if it did I wonder how that would be complicated by coring? Badly, I suspect. I have a tendency to chase rabbits down burrows, more so when I see a boat which fits the bill but turns out to have issues I`d like to solve, but recognize I may not.