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opinions re: epoxy vs. plastic hulls, lead vs. iron keels

10K views 33 replies 10 participants last post by  blt2ski 
#1 ·
hi

interested if anyone has any opinions on the following:

1. Is there any specific disadvantage, other than price and possibly environmental considerations in manufacturing, of an epoxy hull compared to a poly/vinyl-ester hull? (comparing apples to apples - i.e. assuming both cored with same core material)

2. (I know this has been discussed somewhat previously & have looked at the posts) what disadvantages are there to lead versus iron keels.

i ask just because as i look around for next boatie, it seems to me that apart from (relatively) small price differences, there are no disadvantages to epoxy hull and lead keel. i do see some disadvantages to carbon fiber spars.

would be interested in others' thoughts.
 
#4 ·
hi

interested if anyone has any opinions on the following:

1. Is there any specific disadvantage, other than price and possibly environmental considerations in manufacturing, of an epoxy hull compared to a poly/vinyl-ester hull? (comparing apples to apples - i.e. assuming both cored with same core material)
Epoxy is subject to thermal distortion at lower temperatures than poly/vinyester resins, so in the case of most epoxy-composite boats, dark colors are best avoided. However, the will generally be more resistant to osmosis, stronger, and a bit lighter.

2. (I know this has been discussed somewhat previously & have looked at the posts) what disadvantages are there to lead versus iron keels.
Lead is more expensive and more toxic. However, it has a higher density and as such will have less wetted surface area for the same righting moment (weight in ballast). It is also far more forgiving in a collision, with an externally mounted keel, since the lead tends to deform and absorb a lot of the impact energy, rather than transfer it to the keel support structure.

i ask just because as i look around for next boatie, it seems to me that apart from (relatively) small price differences, there are no disadvantages to epoxy hull and lead keel. i do see some disadvantages to carbon fiber spars.

would be interested in others' thoughts.
Carbon fiber spars have a few major disadvantages, especially for a cruising boat in remote regions. First, it isn't as easily repaired, requiring fairly sophisticated materials and techniques to repair it. Second, in a lightning strike, a carbon fiber spar may look fine, but actually have serious delaminated areas and be a serious danger to the boat. Third, there are some serious galvanic corrosion issues with hardware attachment to a carbon fiber spar, given carbon fiber (graphite) relatively high position on the anodic scale.
 
#5 ·
thanks for the replies - much appreciated - perhaps i wasnt totally clear, i am reasonably familiar with the advantages of epoxy hulls/lead keels (and disadvantages of carbon fiber spars), however, i'm looking for any disadvantages of these (apart from, as i mentioned, cost), in anyone's opininions.

i was not aware of the issue of thermal distortion and dark colours, though - interesting - how does that work? if this is true, why do so many tartans have dark hull colours?
 
#6 ·
Well...there is a great deal of difficulty apparently in building a composite epoxy hull and there have been admitted failures. If you read the "Tartan Buyers Pls Note" thread under Buying a boat forums you will see several owners with big time problems and a series of interview links with designer TimJackett that detail some of the issues that had to be worked out...sometimes in production...with the construction techniques and bonding issues. Both Tartan and C&C boats are built using the same technology. I believe the thermal distortion issues around dark hulls Dawg mentions can be solved with outer mat layers of vinylester. The Jackett interviews cover this issue and I think you will find them interesting. Just remember they are the company's views and there are at least two lawsuits currently filed and a number of folks who disagree quite vehemently with Jackett's dismissiveness of some of the issues.
I can't think of any disadvantages to lead keels.
One additional disadvantage of carbon fiber masts is that many insurance companies will insure the boat but not the mast. A guy here a month or two ago lost his due to a lightning strike and insurance excluded it and he had a big bill.
 
#7 ·
My cousin lost a very expensive carbon fiber mast to a lightning strike a week after he put it in. He has good insurance so he just went and got another. But the thing was a total loss - He was lucky he wasnt on the way to Bermuda when it happened.
 
#8 ·
Epoxy, lead & carbon

As an industrial engineer who has worked with advanced materials for many years, I am continuously amazed at how people cling to old technology in the face of overwhelming evidence supporting newer materials. At the outset, I should point out that I own an older Tartan 3500 that does not incorporate the newer technologies (the newer Tartans do) that I mention below. Looking forward to buying a new boat, I've spent a good deal of time investigating these materials choices.

Epoxy resins unquestionably produce a much stronger, lighter and stiffer laminate. The ONLY reason that most sailboat manufacturers continue to use polyester resins is that they cost a fraction of epoxy resins. Epoxy is far more environmentally friendly since it produces no styrenes. Although far more costly to use in the manufacturing process, epoxy resins result in a far superior structural product. Tartan pioneered the use of these resins in their products 6-7 years ago. Others are now starting to follow; Hanse provides an option for epoxy in its larger boats at a considerably higher price. The only reason that manufacturers continue to use polyester resins is COST.

Lead is unquestionably the best choice in materials for keels due to its much higher density, which dramatically influences the designed righting moment. The builders that use iron keels do so soley to save money. The compromise is found in a lesser rig design to accommodate the inferior righting moment. Lead keels also have a much longer life than iron by reason of the corrosion characteristics of iron. Again, the only reason that some builders use iron keels is COST.

Carbon spars are FAR superior to aluminum. They are less than half the weight of aluminum, and are stronger as well. Racing sailors are well familiar with the performance advantages of carbon spars. But as a cruising sailor, the advantages are very apparent as well; less weight aloft produces a much better sailing motion and an easier rig to manage. The suggestion that carbon masts are more susceptible to lightning damage is simply not supported by any facts. Additionally, boats with carbon rigs are fully insurable by all major marine insurers. Again, the only reason that most manufacturers use alloy spars is for reasons of COST.

Most quality sailboat manufacturers have plans to incorporate epoxy resins in their laminates, and provide carbon spars as standard materials. Only considerations of cost keep them from getting there. Tartan go there years ago by investing in advanced materials technologies, and now lead the pack.
 
#9 · (Edited)
i was not aware of the issue of thermal distortion and dark colours, though - interesting - how does that work? if this is true, why do so many tartans have dark hull colours?
Most tartans, until just recently, were standard polyester/vinylester construction, so the thermal deformation wasn't an issue. Cam does mention one possible work around, which is to use several layers of polyester or vinylester resin as a finish coat, but that doesn't always work.

As an industrial engineer who has worked with advanced materials for many years, I am continuously amazed at how people cling to old technology in the face of overwhelming evidence supporting newer materials. At the outset, I should point out that I own an older Tartan 3500 that does not incorporate the newer technologies (the newer Tartans do) that I mention below. Looking forward to buying a new boat, I've spent a good deal of time investigating these materials choices.

Epoxy resins unquestionably produce a much stronger, lighter and stiffer laminate. The ONLY reason that most sailboat manufacturers continue to use polyester resins is that they cost a fraction of epoxy resins. Epoxy is far more environmentally friendly since it produces no styrenes. Although far more costly to use in the manufacturing process, epoxy resins result in a far superior structural product. Tartan pioneered the use of these resins in their products 6-7 years ago. Others are now starting to follow; Hanse provides an option for epoxy in its larger boats at a considerably higher price. The only reason that manufacturers continue to use polyester resins is COST.
I would say that Tartan still has some serious issues to work out with their Epoxy-based laminates at the moment.

Lead is unquestionably the best choice in materials for keels due to its much higher density, which dramatically influences the designed righting moment. The builders that use iron keels do so soley to save money. The compromise is found in a lesser rig design to accommodate the inferior righting moment. Lead keels also have a much longer life than iron by reason of the corrosion characteristics of iron. Again, the only reason that some builders use iron keels is COST.
If density was really the primary characteristic for a good keel material, they'd be using Osmium or Iridium, either of which has almost twice the density of Lead. Lead is 11.34 g/cc, where Osmium is 22.6 g/cc or thereabouts. Osmium is also fairly toxic, and the Osmium tetraoxide compounds are lethal... :) Lead is the best reasonably priced material for keels, and its relative malleability can also help protect the boat in the case of a hard grounding-since lead will often deform and absorb much of the energy in a hard grounding, rather than transmitting the force directly to the keel-hull join.

Carbon spars are FAR superior to aluminum. They are less than half the weight of aluminum, and are stronger as well. Racing sailors are well familiar with the performance advantages of carbon spars. But as a cruising sailor, the advantages are very apparent as well; less weight aloft produces a much better sailing motion and an easier rig to manage. The suggestion that carbon masts are more susceptible to lightning damage is simply not supported by any facts. Additionally, boats with carbon rigs are fully insurable by all major marine insurers. Again, the only reason that most manufacturers use alloy spars is for reasons of COST.
Actually, they are far more susceptible to difficult to diagnose lightning related damage, since the surface may appear fine, but the interior of the laminate could be damaged and delaminating with little or no warning of the impending failure.

Most quality sailboat manufacturers have plans to incorporate epoxy resins in their laminates, and provide carbon spars as standard materials. Only considerations of cost keep them from getting there. Tartan go there years ago by investing in advanced materials technologies, and now lead the pack.
This is a really bad blanket statement... as many manufacturers have no plans to use epoxy due to cost and no reason to go to carbon fiber spars due to cost and manufacturing complexity. Tartan isn't really there yet-since they're having serious manufacturing defects with their epoxy-resin boats... I'd say they're still a work in progress. :rolleyes::rolleyes:

Given Tartan's recent track record, and how they've basically screwed a lot of the more recent buyers of the marque.... I am surprised to see a Tartan owner defending the brand ATM.
 
#10 ·
Carlsbad...suggest you read the "prospective Tartan buyers thread" before you dismiss those of us who think there is more than clinging to old technology going on when we choose NOT to embrace epoxy.

As to carbon fiber masts...you are correct that the are no more likely to be hit by lightning than aluminum. On aluminum boats you are unlikely to need a mast replacement due to a strike since the rig usually stays up. If a carbon mast is damaged, you have to replace the whole thing. If you are a cruiser outside of the US...just try getting any work done in the Caribe or Mexico for example...whereas someone can always fix an aluminum mast.
Carbon has a lot of performance advantages and can eliminate the need for shrouds and chain plates and other conventional rig complications...so there is a place for it in the market but cruisers should be aware of the disadvantages as well as the advantages. I stand by my insurance issue...the guy with the Freedom here a couple of weeks ago specifically had the carbon mast excluded from coverage. This is not to say that others will not insure one...but you may be paying a premium for that coverage.

BTW...if cost is the only issue with Epoxy...why are MORE costly brands such as Hinckley, Oyster etc. not using it already? Hinckley is doing some carbon masts but chooses NOT to use epoxy.
 
#11 ·
"Given Tartan's recent track record, and how they've basically screwed a lot of the more recent buyers of the marque.... I am surprised to see a Tartan owner defending the brand ATM."

Lots of Tartan bashing from non Tartan owners. I don't get it. We know of one unhappy 3700 owner and one unhappy C&C 121 owner (from the blogs) and all the non Tartan owners come rushing in with their expert opinions on all new Tartan and C&Cs.

I'm a 3400 owner and Tartan has done a wonderful job in backing all my warranty claims. I also now other 3400 owners and a few 115 owners that are happy.

I'm convinced Tartan and C&C build the best laminate in the business. A C&C 115, on the hard, recently fell off its stands in a windstorm, crashing to the ground on its side. The boat was surveyed with nothing more than cosmetic scrape on the side of the hull where it hit the concrete. The same incident also happened to a new Jeaneau Sun Odysee and totaled it (I think Jeaneau makes a fine boat).

Obviously the benefits of epoxy laminate are real and that 115 was built right.
 
#12 ·
monteh & all ...let's move any further Tartan/C&C specific discussion to that thread under "Buying a boat" so we can keep all the relevant facts and opinions in one place.
My point for this thread is that epoxy boat building is difficult to do right and even Jacketts details some of the problems encountered in production just a few years ago and it is not simply a matter of builders being too cheap to use it as Carlsbad said.
 
#14 ·
Argle,

Not with standing the Tartan/C&C debacle. A correctly built epoxy boat as stated will be lighter and stronger. MOST epoxy boats have been, or at least I seem to see, custom racing sleds of some sort, with the last 5'ish yrs lead by Tartan/C&C the attempt at putting production boats out made of epoxy. Not with standing the problems, a C&C 99 or 115 even a 110 would be on my short list if there was not the build problems, maybe only 2 real problems on my list of boats to buy.

Lead vs steel, take your pick. As you know with your Attalia, and so far with my Arcadia, steel keels work. A combo is probably the best of both worlds if you will.

Alum vs carbon. I'd take a carbon over an alum. If my mast went south tomorrow, I would get a carbon mast over replacing it with alum. Some have mentioned the lightening aspect. But in all honesty, we here in the NW US/SW Canada ie puget sound st of georgia like you are in, do not get the coud to ground lightening strikes like back east. Most lightening is cloud to cloud around here when we have a storm. I do not see as big an issue as maybe back east, but then again, knowing my pention for attempting to have the best tech I can within my budget..........away we go.

In the end, choose the material that will work best for you, with the plus's and minus's that suit you. Just like Cam has a shoal draft boat, ketch rig, I'd personally look for the deepest draft sloop rig of the same style, as we here really do not need to deal with the bridge and draft constraints he does on the east coast. Again it is a choose what works for you here in this area, not east coast if this is where you will sail for the time being.

On the other hand, if you want to stay with Jeanneau, I would look at the newer SO 35 or 37, if you want a bit more performance, look at the sunfast versions.

Marty
 
#15 ·
Of course, a lot of this all depends on what you're using the boat for. If you're planning on a long South Pacific cruise...an aluminum mast would probably make far more sense... getting a carbon fiber mast repaired in the Southern Pacific in case of trouble might be a bit difficult.
 
#16 ·
I don'y know alot about carbon fibre masts but I can tell you I own a 42 year old wooden boat that was epoxy coated ( cold moulded with 3 tonnes or lead keel and I just returned home from a 48 knottical mile trip with 10 foot waves in just less than 7.5 hours and the old girl did not leak a drop (other than my rum that broke after the second pound thru the waves .
 
#17 ·
The question should be, are epoxy laminates doable at production run speeds if that is a way to call it. Still, if I had a choice I would go with epoxy over std plastic laminates. My step dad was using epoxy based items at boeing back it he late 60's and early 70's. Even coated the plywood boat he has been building for not sure how long with epoxy before it was even thought about generally speaking, ie late 70's!

One should not blast ALL epoxy based boats on the Tartan/C&C debacle that is going on. I have around puget sound any way, not seen any issues with Tartans, but do know of a couple of C&C 115's with some laminate issues. Mostly gelcoat issues, nothing structural. That still does not say to me that epoxy is NOT the way to go. Chevy was flamed for using fiberglass on the early corvettes. Now 40 some odd yrs later, the outside of my pickup bed is made of fiberglass! as are other parts of the truck!

Personally I do not see a reason to flame new tech, if it is not able to work for me at this time. I have seen it in my profession, where version 1 worked reasonably well, version 2 equal to old tech, version 3 better than old tech, and old tech is on the way out! Might take a few yrs, and multiple suppliers trying to work with it, but epoxy may as the price comes down, become the main ingredient of boat hulls, then again............it could end up something else. Was there not a time when folks said wood was what boats had to be made of, not plastic!

Anyway, off to work.

Marty
 
#18 ·
carlsbad,

I have NO doubt in what you say for the most part. As I spent about 2 months racing weekly including the Seattle NOOD's on a C&C 115. Unfortunetly, that boat does have some serious gelcoat issues! ie the white is light tan! just plain ugly! A very bad job. The other boats looked very nice in comparison.

My main issue for the most part, are folks like SD that bash or seem to bash "EVERY" boat made of the substance, ie epoxy, when there are probably many many more boats out there than the two or three that were major problemed. The Tartan 3700 couple got the boat fixed, and are still sailing it, the folks with the 115 and I believe a 121 are the ones causing the most stink!

As I said IIRC earlier in this post, I personally would take an Epoxy boat over a typical fiberglass resin boat if the cost was effective to me. Hence why the C&C boats due fit my preferences for a boat if I could afford a new boat right now. With the 99, 115, then 110 in that order of preference. The Tartans, while nice boats, do not fit my performance/race wants and needs.

Some of this does not make sense, it may very well have been a bad batch of epoxy, similar to the bad resins in the 70's, where it seems a lot of boat have blisters! THen again, they may have hired a bunch of druggies at the time!

Marty
 
#19 ·
Marty...you are a little incorrect in that two owners presently have suits against Tartan/Novis. But I take your point that no legal proof is yet in that these two boats were Novis' fault and no proof is yet in that there are widespread problems with overall quality. Nor is there proof that there are not significant issues with an abnormal % of these boats. We'll get our answers on those issues + I'm sure a lot of very interesting details when those cases are decided this fall. Even if these cases are proven on behalf of the plaintiffs...it does NOT prove that epoxy is a bad material...just that how it was used was at fault. I will keep my comments on the Tartan situation over on the Tartan thread.

I think what can be said at this point is that epoxy is a material with a lot of benefits if done correctly...and others have pointed out some examples of one-off's that have done admirably and Tartans and C&C's that are just fine with no significant problems. But it is also evident that the production type building of epoxy boats presents a real challenge and we have evidence in Jacketts (Tartan/C&C) own statements that significant changes had to be made during production due to unsatisfactory results with prior methods. No one seems to have any data on Hanse boats with this option so all one can say about epoxy I think is that it is still pretty new and unproven in use on production boats. Some may like to be on the cutting edge with this given the potential benefits...others may feel more comfortable with a wait and see position.
 
#20 ·
Tartan/C&C have made over 300 boats with epoxy resin systems. As an industrial engineer and future buyer of a Tartan 4300, that's enough experience for me. Epoxy resin systems have been used successfully in composite manufacturing in other industries for many years.

I asked Tartan about the two lawsuits that Cam has frequently mentioned (again in today's posting) on this site. I have had time to check out only one; the one in Texas. As a consulting engineer, I sometimes provide consulting engineering services to insurance companies and parties to lawsuits. Tartan's people say the lawsuit is about a Yanmar saildrive unit that experienced corrosion on a Tartan 3700. I called the Yanmar distributor's office several months ago, and they acknowledged that the lawsuit was about a Yanmar saildrive unit, but in their view, it was the owner's fault for not properly maintaining it. No big surprise there. But that case has nothing to do with epoxy composite technology.

In the late 50's and early 60's when boat manufacturing changed from wooden construction to fiberglass, lots of owners clung to the belief that wood was better. Some still do! Nothing looks as good as a classic well-maintained wooden boat. Buts its pure romance, not science.
 
#21 ·
Cam,

Your last paragraph says what I am attempting at saying. Epoxy has shown its benefits when done correctly. Both with one off boats, and to a degree with the Novis built boats. I will also admit, as they seem to to a point, had/have some learnig curves when using this product. Hanse is making some boats optional, other this is std, ie epoxy.

If Arglebargle is looking at a Hanse since he mentioned it, at the local Vanouver BC dealer, he likes the boat......buy it! The main thing I am seeing so far with my friends 115, is the manufacture is dragging its assets in admiting the surface gelcoat issue and fixing it, then they are more than happy with there 2nd? C&C boat, the previous being a fiberglass 38'r.

ANyway, as far as which tech, take your pick for where you sail etc.

Marty
 
#22 ·
NOTE TO ALL.
Any further posts on this thread or forum either bashing or defending the Tartan & C&C brands will be deleted. This is about boat construction materials and methods. You can discuss METHODS and MATERIALS used by different brands but NOT the brands themselves. Go to the brand threads and forums for OPINIONS about boats and brands.
 
#24 ·
OK, perhaps this will move the thread back to topic:

So why, exactly, is epoxy resin "better" than polyester resin for fiberglass sailboats?

We've heard statements such as
I'd like to see better reasons than "because it's old". For instance, modern steels are made with the basic oxygen method, which is 1950s technology, yet does anyone argue against cars made of steel since steel is "old" technology?

For the record, the Boston Whaler 13 debuted at the 1958 Boston Boat Show. It was made with epoxy resin. (Source: "Heart of Glass: Fiberglass Boats and the Men Who Built Them" by Daniel Spurr, page 155.) Production of boats using polyester resin started in the late 1940s. The Marco patent (U.S. Pat. No. 2,495,640) for the resin infusion process was filed June 8, 1945. None of this stuff is new, revolutionary technology.

I was wondering why there was a reference to the 1960s, until I came across a particular boatbuilder's page that said:
"Just as the introduction of polyester fiberglass laminates replaced wood yacht construction in the early 1960's, (builder's name) new epoxy laminate now makes those earlier lamination techniques obsolete."​

So, perhaps I'll ask for more authoritative sources than advertising literature when describing why epoxy is better than polyester resin.

Cheers,

Tim
 
#25 ·
Epoxy is a better glue in five major areas:

1. Better adhesive properties (the ability to bond to the
reinforcement or core)

2. Superior mechanical properties (particularly strength and
stiffness)

3. Improved resistance to fatigue and micro cracking

4. Reduced degradation from water ingress (diminution of
properties due to water penetration)

5. Increased resistance to osmosis (surface degradation due to
water permeability)

The disadvantage is that it is harder to work with relative to poly/vinal. Which means, maybe you don't want a Monday hull. :)
 
#27 ·
Epoxy is a better glue in five major areas:

1. Better adhesive properties (the ability to bond to the
reinforcement or core)
Yes, I can see that. Epoxy sticks to wood far better than polyester resin. I would only tab bulkheads using epoxy (or at least vinylester) resin.

The only other place I can think of where adhesive properties is important is the laminate-to-core bond. When I've ever come across delamination in a sailboat, it's always been after core has gotten wet. Do we know if wet balsa sticks to epoxy better than it does to polyester resin? I once looked into injecting epoxy into a soft deck, but all the epoxy products I could find insisted the core had to be completely dry.

2. Superior mechanical properties (particularly strength and
stiffness)
Numbers I found for tensile strength of the resins are 7,000 psi for ortho polyester and 7,960 psi for epoxy (source: Marine Composites Handbook, table 2.7).

That's about 14% higher, but it's actually the glass reinforcement that provides most of the strength and stiffness in a laminate, not the resin. A blend of glass and resin isn't going to be as sensitive to changes in resin strength, so the actual improvement for the total laminate will be considerably less than 14%. (The only production builder using epoxy resins uses E-glass reinforcement, which is the economy fiberglass normally used by other production builders so their reinforcement isn't any stronger.) I couldn't find what the difference in strength and stiffness would be for a completed panel using e-glass and epoxy vs. polyester.

3. Improved resistance to fatigue and micro cracking
Paul Miller of the U.S. Naval Academy studied fatigue of J/24s which are light weight, cored hull boats. His "high mileage" sample boat had an estimated 11,300 hours of use in a sailing school in the roughest part of San Fransisco Bay over 14 years. He measured the stiffness of this boat had dropped by 18% due to fatigue and micro-cracking.

That's a fairly extreme boat usage example, yet the boat was still far from failing. Is fatigue and micro-cracking a real problem on production sailboats using polyester resin?

4. Reduced degradation from water ingress (diminution of
properties due to water penetration)
There was an old study of early USCG 40 foot patrol boats (built in 1952) to see how fiberglass properties changed with age and exposure to water. To quote:

"In 1962, Owens-Corning Fiberglass and the U.S. Coast Guard tested panels cut from three boats that had been in service 10 years. In 1972, more extensive tests were performed on a larger population of samples taken from CG Hull 40503, which was being retired after 20 years in service. It should be noted that service included duty in an extremely polluted ship channel where contact with sulfuric acid was constant and exposure to extreme temperatures during one fire fighting episode. Total operating hours for the vessel was 11,654. Visual examination of sliced specimens indicated that water or other chemical reactants had not entered the laminate. The comparative physical test data is presented in Table 4-5."​

The properties in the table didn't change much. Probably epoxy would have performed better, but there are a lot of old polyester fiberglass boats (Pearson Tritons are coming up to their 50th birthdays) that still seem to be OK.

5. Increased resistance to osmosis (surface degradation due to
water permeability)
This is certainly true. But how bad is blistering on newer (< 10 years old) boats? Many builders have been using iso-gelcoats and vinylester skincoats, which seem to work pretty well. I know Island Packet offers a 10 year warranty against blisters.

So, yes, I can see that epoxy resin by itself does have better properties than polyester resin, but when it's combined into the total system of a production sailboat, is the total boat measurably better? No doubt the boat will be more expensive, but do we have real benefits to offset that cost? Or, put another way, is using epoxy solving real problems rather than perceived problems?

Cheers,

Tim
 
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