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KevinBarr 05-06-2009 05:36 PM

Hi Folks,

I am hoping to tap into your collective experience in creating a shortlist of boats that have a solid fiberglass hull without core material. It is my understanding at this point that older boats have a solid hull, but that this changed sometime in the 80's? I have gleaned that the Rawson 30 is an older boat that has a solid fiberglass hull? I understand the speed-wieght tradeoff but I have never been much of one to get there fast as that kind of defeats the purpose for me.

A lot of what I have read here has given me food for thought and leads that I could follow up to expand the research I have been doing. One thing that I am having trouble with is how to determine those boats that have cores and those that are solid fiberglass. Does anyone know of a way of finding out about their composition other than researching each boat at a time, individually?



redbopeep 05-06-2009 06:00 PM

When we saw a boat advertised that looked interesting to us, if we didn't know what it was we'd look into it--owners' groups etc. There, you find a lot of info. Then, of course, one begins to have a "list" of boats of interest to them. Fairly quickly, we moved away from classic fiberglass boats into pre-WWII wood boats as we decided that we wanted to combine our interest in historic preservation with our desire to voyage on a sailboat. Therefore, my research is basically useless to you.

You can request a sailboat hull surveyor to help you in your search--if it is someone in their 50's or 60's or older, they will usually have encyclopedic knowledge of boat construction. Further, they are likely to know of reference books available to surveyors.

USA-built boats that were designed in the 1950's or early 1960's would be likely to be solid fiberglass (this would include the Rawson 30 which was designed in 1957-58 timeframe). If the earliest year a boat was built is after 1975-ish, there is likely to be core material unless the boat is quite large and then it might still be solid fiberglass. If you're only looking at small boats, you'll likely find core materials show up somewhere in the 70's build dates.

Sorry I don't know a more methodical way to learn which hulls are solid fiberglass. I hope other CL contributors can help us out here with additional knowledge.

Fair winds,

osirissailing 05-09-2009 11:23 PM

You did not specify whether you are interested in power boats or sail boats. Generally, powerboats have cored hulls below the waterline. Generally older monohull sailboats have solid hulls below the waterline and are mixed about whether they are cored or solid above the waterline. Decks are normally cored in the walking areas.

** But be careful, newer or the newest sailboats do follow the convention for solid hulls below the waterline, but are now making them drastically thin. I just looked at a new Dufur 50 that went on the rocks here in Martinique and had its lower hull ripped apart by the rocks. It was only about one quarter inch / 6mm thick which is less than a third of the standard for a 50ft / 16m boat. The new fiberglass materials and techniques allow stronger hulls that are much thinner than traditional hand laid hulls. But put them on the rocks or in a collision and they are like eggshells. So look for both features - cored/solid and thickness. ABYC and other "standards" organizations have guidelines for the thickness of hulls versus LOA. But they are only guidelines and as manufactures try to cut production costs to keep prices down, such standards are ignored or "revised."

delatbabel 05-10-2009 01:16 AM

Any boat where you can watch the sun set through the hull ... don't buy it. And I've seen a few.

KevinBarr 05-11-2009 12:12 PM

Thanks for the tips, tout le monde!

I am not so much looking to buy at the moment as inform myself of what is out there. Leaving aside the "newer, newest" boats for the moment, can anyone identify some models that are solid fiberglass?



Wildernesstech 05-12-2009 02:51 AM

The Alberg 35 and the Pearson Vanguard come to mind, both being tied up at the dock I am sending this from... 1964 & 1966 respectively.

redcobra 05-12-2009 03:03 AM


Originally Posted by Wildernesstech (Post 33212)
The Alberg 35 and the Pearson Vanguard come to mind, both being tied up at the dock I am sending this from... 1964 & 1966 respectively.

My Alberg 30 (66) was solid fiberglass hull while the topsides were masonite cored fiberglass. Might as well have been solid fg.

Trim50 05-12-2009 03:25 AM

Seems the 1966 Cal 40 has some delam issues...

osirissailing 05-12-2009 01:45 PM

Almost all of the monohull sailboats below 50 feet LOA are solid FRG below the waterline. Any boats built before the mid-1990's will be suffering osmotic blisters and possibly delamination depending upon the manufacturers techniques used to lay-up the layers of fiberglass. After the mid-1990's the manufacturers switched the resin they were using and improved the lay-up techniques to greatly reduce "osmotic blisters" problems. The better manufacturers began offering 10-year warranty's on blisters while the "problem/suspect" manufacturers offered only 5-year or no warranties on blisters. Since it takes an average of 10 years for blisters to appear any warranties below 10 years are worthless and the manufacturers are "suspect."

You can easily detect cored hulls by tapping on the hull with a ballpeen hammer or similar steel/hard iron tool. The sound is distinctly different. Actually a bright light or sunlight will pass through solid laminate hulls while not through cored hulls so it is not a good indicator.

Very few reputable manufacturers of sailboats will use "cored hulls" below the waterline. One-off and specialty racing sailboats will used cored hulls to reduce dramatically the weight of the boat and therefore increase the speed/acceleration potentials. But these boats are only designed for a few races and then "thrown away". Delamination of cored hull racing boats in long distance ocean racing was a major and frequent problem which convinced the recreational sailboat builders to avoid cored hulls below the waterline. The major issue now is whether the solid FRG hull is thick enough to withstand the pounding and occasional grounding and reef encounters. The technology of FRG hulls was not very advanced in the "olden" days so the builders built the hulls "extra-thick" to allow for design errors. Modern manufacturers now have sophisticated design computers and build with minimal thickness to reduce cost of materials and weight. That is fine for "marina" boats and "coastal" boats that will never see the "big" ocean or the unmarked rocks and reefs found elsewhere in the world. "Blue water" boats are built strong and heavy and as a result are also slow and not very nimble. So if your intentions are to sail the world - look for a "blue water" boat. If your intentions are week-end or island sailing then the lighter, thinner-hulled boats are fine. They are faster and more agile and subsequently more fun. But like a sports car versus a "Mack-truck" they are designed for different purposes and operating environments.

KevinBarr 05-14-2009 06:55 PM

So I have a list of the Rawson, Alberg, and the Pearson Vanguard. No Rawsons for sale, at this time. I have found an Alberg from 1966 and another from 1978. Did Alberg change their processes at all? Did they still produce solid fiberglass in 1978? One is selling for 15K and the other is going for almost 19K.

By the way, is there a way to check the integrity of the fiberglass hull?

Thanks for answering my questions!>/biggrin.gif


Wildernesstech 05-21-2009 04:47 PM

Yes... There is a way to check the integrity of a FRG hull... It is called a "SURVEY"! Doing without one is a gamble, but the quality and experience of the surveyor is what tells the story. I have not always got one, but learned to do so fast!


osirissailing 05-22-2009 01:08 PM

The vast majority of "blisters" on FRG hulls are "gel-coat blisters" and are a cosmetic problem and not a structural problem. With the boat on the hard you will see the hundreds if not thousands of little "bubble" blisters usually from 1/4 inch to one inch in size. "Laminate blisters" are a structural problem and will show up as you sight down the hull with your head close to the surface of the hull. They will be much larger "domes" compared to gelcoat blisters. Tap the hull with the round end of a ball peen hammer and listen to the tone of the sound. Solid laminate will sound sharp and high while blisters will sound "Thud-ish" or dull. Tapping around a suspect spot and you will hear the definite difference in sound between solid and blisters. Also it takes about a week on the hard before some of the laminate blisters will show up.

Books talk about "core samples" and furnace burn tests. Core drilling a prospective boat will definitely not make the present owner happy and even if you own the boat you are left with lots of holes - like swiss cheese - through your hull and a major expense of patching these holes. So it is not a viable or logical way to test a hull. Besides an area 2 feet away from your "core sample" will have totally different characteristics.

Gel coat blisters are an easy fix by peeling the gelcoat off or sanding it off and then patching any remaining cavities. Then apply a reputable barrier coating system and repaint the bottom with anti-fouling paint.

Laminate blisters require extensive drying of the hull which can take many months on the hard and then expert grinding out the compromised fiberglass; dishing the resultant cavity and then laying up new polyester resin and fiberglass cloth to restore the original hull surface. ** And there was a major change in the resin used in the mid 1990's so make sure you use the same type of polyester resin as the original hull. **

Fiberglass hulls are "ultimately" repairable which means whole sections can be ripped out or damaged and with proper techniques the repairs will restore the original integrity of the hull. However, beside the shell of the hull - if there is major damage due to grounding or collisions - you must inspect and restore the interior bonding between bulkheads and the hull shell. That can be quite involved and not cost effective. Be sure to find out if your prospective boat has had a collision or major grounding incident and repairs before considering purchase. FRG hulls are laid / constructed with stress analysis considerations determining the orientation of the fiberglass lay-up. Repairs to severely damaged hulls without considering such factors - a very common problem with "native workers" - can result in the repair separating from the original hull at the most inopportune times while many miles from shore.

KevinBarr 05-22-2009 01:50 PM

Thanks Osiris! THAT was exactly what I needed. I found a course being offered this fall at one of the local sailing schools where they bring in lads who work with fiberglass and teach how it is done, particularly for this special application.


Apolima 05-28-2009 11:21 PM

Hi all,

Just a quick note on my experiences with cored hulls. Over 30 years ago I ordered a boat built that was designed with a "Airex Core" hull and balsa core decks. It was light, fast and roomy. Took my wife and 4 kids to Alaska on shakedown then down the west coast and on to the South Pacific. Five years later hull was waterlogged below waterline, chain plates raising deck off bulkheads 2" and stainless bolts below waterline suffering from oxygen-starvation corrosion. Good boat for local cruising but not for serious offshore work.

My Present boat, A Durbeck 46, has an overbuilt solid glass hull which does not pant, pump or flex when sailing. Overbuilt? Yes. Overweight? Yes if you want to surf on a reach or downwind. To me it is a safe, sea kindly boat that will take me anywhere I want to go and back. Previous owners have done the Antartic,The Horn, all the southern capes and more.

To each his own. So far our government bureaucracies have not dictated how we can sail so it is up to each one of us to decide what is right for us.

Pleasant sailing all.

KevinBarr 05-29-2009 03:21 PM

Apolima, that is a beautiful boat. I don't think I will be able to go for a 42' right off the bat you never what might happen eventually. I went looking for info on the Durbeck but I could not find a company web-page or a spec sheet. Do they make smaller boats? I will keep looking...


SeaVenture 06-06-2009 12:33 AM

Sea Venture has one of those overbuilt, solid glass hulls. Nary a blister, and she was built in 1977. Her teak decks needed replacing when we bought her in 2003, but the rest of her was solid -- so well built that she managed to go up in a waterspout off Central America with her owners watching (assuming the worst, of course), and then land with the only damage being that sustained to the port aft quarter rail. Fascinating story, which explained the less than stellar wood work on that rail.

She has taken us in big seas and 47 knots coming south from SF to Mexico, smaller seas but not very nice ones off Isla Ceralvo near La Paz in winds on the nose of 50 plus. She lost her engine north of Cabo and sailed us over to Mazatlan for a repair. We love the fact that when replacing all the thru hulls, we saw the thick underbody and now have experience with her hull integrity. She won't win most races around the buoys, but she'll keep afloat in the bad weather.

KevinBarr 06-08-2009 12:35 PM

Ah, it took some digging on your web page, but SeaVenture is a Hudson Force 50. That is a BIG boat, but very pretty. Two masts. That must be a lot of work!

Johnde 08-25-2016 01:15 AM

Durbeck 46
Apolima, I am looking at a Durbeck for sale. Please tell us more about the construction and the positives and negatives you have found with your Durbeck. Thanks very much.

haiqu 08-25-2016 03:21 AM

Yet another necropost. Last entry on this thread was in 2009.

Cowboy Cruiser 08-25-2016 11:52 AM

What's 7 years among friends!

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