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Go Back   SailNet Community > On Board > Boat Review and Purchase Forum > Sailboat Design and Construction > opinions re: epoxy vs. plastic hulls, lead vs. iron keels
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Thread: opinions re: epoxy vs. plastic hulls, lead vs. iron keels Reply to Thread
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Topic Review (Newest First)
08-12-2008 11:21 AM
blt2ski I have yet to make it to Sucia, Fartherst north on that side I have been is Clark island. Nor did I make it to Bedwell. Either you or I would have been oldest and smallest boats. Most were mid 90's and later SO models.

As far as the bay getting into it, if 6-9' is the least, you should be ok if you stay in the deeper area's.

Not sure I would worry about the debris in the water puncturing a hole in the hull. If you had a power boat going 20+ knots..........that might be a different story. What is the difference in price on the iron vs iron/lead deep keel? and is there any difference in overall ballast or disp?

We stopped at Roche on the way back from bedwell last yr, 1st time for me being there, nice little spot, would like to have stayed longer than the hr or so we were there, but spouse needed to be home that night, so off we went south!

I also wondered if Richard had left Freedom yachts, as there website shows a need for a broker, and richard was not one of the folks listed anymore! Not that we would/would not see him in Sept or Feb shows then, unless he is showing a Bavaria, as I am sure the local T/C&C dealer would make sure they are kept out of Seattle's show, probably more of a franchise type reason than anything.

Congrats on the upcoming marriage/honeymoon, hope all goes well.
We may be up there the first part of sept. I've been working on Crane over the last month or so.

Marty
08-12-2008 03:03 AM
ArgleBargle 37 base price was 178 earlier this year (not including commisioning, taxes or much else). we're just looking and thinking still, but i am enjoying the epoxy-glass and lead keel discussion and find it quite educational. thanks for all of the various responses.

i had thought a lot about it and one thing (possible epoxy disadvantage) i thought might come up, but hasnt yet, is puncture resistance. if the tensile strength is so much greater, to realize the weight savings, presumably the laminate is thinner (i dont know this as a fact, however), especially if cored. i think about this when avoiding the sometimes impressive number of logs we see around here. perhaps this isnt the case with a marginal increase in strength like switching to epoxy, but i imagine taken to the extreme (say, carbon fiber/epoxy composite) built to the same stiffness as a GRP hull, it would be rather fragile.

blt2ski yes, we have met with richard in vancouver, but as it turns out he moved to the tartan/C&C/bavaria dealer - we found out by surprise as we were looking at a tartan 3700 CCR this past weekend (which along with the hanse brings up the discussion of the merits and deficiencies of self tacking headsails, but i think that was another thread). btw, sorry we weren't at bedwell in june, we were actually at roche harbor that weekend - nice little place! we're stopping at Sucia Is on our honeymoon later this month, perhaps you might know if Shallow Bay is too shallow for a 5 and a half foot draft? the books say 1 to 1 1/2 fa, so i figured coming in on a flood tide would be reasonable (??)
08-11-2008 11:58 PM
blt2ski Argle,

Not sure of the base price of a 37, the 32 is 142K and 35 is 177K from a yr ago, assuming a 30-40K increase for the 37 as there is in between the 32 an 35, or about 210K base for the 37. About a 5% increase for the epoxy vs FG. Along with about a 6-7% reduction in wt.........I probably would go for it.

Not sure of cost for the iron/lead keel option vs the std deep draft iron, but might consider that one too, if some overall wt can be dropped from below too. That would help on our lazy less than 10knot summer days.

I do not see a Carbon mast or equal composite option so alum sounds std and the only option there.

Who are you dealing with? Usually we saw Richard here at the Seattle shows.

Good luck on choice if you go that way,

Marty
08-11-2008 11:28 PM
sailingdog Gramp-

I think your analysis is a bit flawed. The mechanical properties of a laminate have a lot to do with how well the resin sticks to the reinforcing fibers. I'd imagine that epoxy's stronger adhesive bonding properties would apply to both the fiberglass fibers as well as any core material.
08-11-2008 11:24 PM
ArgleBargle on hanse 370/400 (+/- "e") additional price for epoxy are 9 553 and 10 897 US$ and 6400/7300 euros.
08-11-2008 08:46 PM
blt2ski Unfortunetly I only have current pricing for the 35 and 32 versions, which do not have the "E" option. The 37 does, IRC about a 1000 lb drop in wt. I am recalling 15K vs 14K for the E version. I do not have pricing on the 37, as that is a bit bigger than spouse and I want to go when we go bigger, then again, who knows, just might of the$$ are there etc. I am also recalling about a $10K option, do NOT quote me on that. Might be less, might be more, how much?!?!?!?!?!

1000 lbs for a boat that size, certainly would give one a bit more SA/disp figure. If one is looking at strictly performance, should be worth it in lighter airs, which I get here in the NW puget sound region frequently. Last 3 races were in winds less than 6 knots!

"ON edit!"
For the 37, the difference is 900 lbs, 15900 vs 15K lbs. SA/Disp is 19-1 for the FG version, and 19.78 for the epoxy version. The 40 is 1100 lbs lighter, the 430 is about 1000 lbs lighter per the website. I'm not going to do the SA/disp figures, as they should be in the +.5 to 1 increase similar to the 370.

Marty
08-11-2008 08:28 PM
monteh Interesting data. As for the cost to value question, anyone know how much extra Hanse charges for an epoxy hull and if it's any lighter?
08-11-2008 07:37 PM
Gramp34
Quote:
Originally Posted by monteh View Post
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.

Quote:
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.

Quote:
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?

Quote:
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.

Quote:
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
08-11-2008 03:36 PM
blt2ski Or maybe a friday before spring break or some such other long company shut down?!?!?! vs a monday hull?

Marty
08-11-2008 03:19 PM
monteh 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.
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