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Old 03-07-2015, 05:35   #61
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Re: Solid Fiberglass Monohulls, a list

Yes that list is way wrong, nicholson 31 definetly cored, wouldn't rely on it to make any decisions.
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Old 20-08-2017, 21:43   #62
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Re: Solid Fiberglass Monohulls, a list

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Originally Posted by maj75 View Post
I've done a search, trying to find a list of solid fiberglass boats, i.e.: no core in deck or hull. I've read descriptions on Yachtworld. So far, I can't find much definitive information. A lot of opinions, or second hand knowledge. There is a thread in the Construction section right now regarding balsa coring, that prompted this post.

The topic comes up all the time, but there doesn't seem to be any definitive list. Please list any sailboats that you KNOW are solid fiberglass.

Thanks
Some of the boats people are listing here have solid hulls, NOT solid decks. The Spencer 35 has a balsa cored deck, as does the Block Island 40. Solid decks are rare. Unless very carefully designed and built, a solid fiberglass deck would be heavy in exactly the WRONG place (up high), raising the center of gravity, increasing the boat's tendency to heel, and reducing it's tendency to get upright again in the event of a knockdown. None of this matters as much in a multi hull. In a monohull, it's a bad idea. That's why you rarely, if ever see it.
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Old 20-08-2017, 22:06   #63
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Re: Solid Fiberglass Monohulls, a list

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Some of the boats people are listing here have solid hulls, NOT solid decks. The Spencer 35 has a balsa cored deck, as does the Block Island 40. Solid decks are rare. Unless very carefully designed and built, a solid fiberglass deck would be heavy in exactly the WRONG place (up high), raising the center of gravity, increasing the boat's tendency to heel, and reducing it's tendency to get upright again in the event of a knockdown. None of this matters as much in a multi hull. In a monohull, it's a bad idea. That's why you rarely, if ever see it.
The original Spencer 35 has a solid glass deck. The MKII is cored with foam I believe, same as the hull.
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Old 20-08-2017, 22:54   #64
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Re: Solid Fiberglass Monohulls, a list

My islander bahama 24 solid glass, my 63 columbia defender solid glass no core.
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Old 20-08-2017, 23:26   #65
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Re: Solid Fiberglass Monohulls, a list

My '78 Hunter has solid hull, but cored decks and most of the coach roof side appears to be hollow! It is stiff as hell, but hollow nonetheless. Makes wiring a little easier, but still makes me wonder..

The hull is pretty thick, and the mast step on the coach roof is either balsa core or plywood, I will find out which very soon now.

It will likely become epoxy and glass over ply, or maybe just epoxy and glass solid, depending upon what I can find about changing the modulus of torsion and flexibility by changing the material properties in the rebedding process will do to the overall safety and longevity of the repair. I don't want to create an additional issue where only a collapsing core is currently the problem...
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Old 21-08-2017, 03:14   #66
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Re: Solid Fiberglass Monohulls, a list

Outbound's hull is 100% hand-laid solid fiberglass and the deck is vacuum bagged Divinycel
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Old 22-08-2017, 13:25   #67
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Re: Solid Fiberglass Monohulls, a list

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Actually I'd be pretty surprised if any of those boats had solid fiberglass decks. And why would you want that anyway?
Solid fiberglass if properly maintained lasts 50.000 years - (so I am told ) - But I have read a lot about "soft" decks and delemaniation. No problem in new boats - but a lot of boats are 30-40-50 years old before they are affordable to some people. Maybe the core was not made to last that long.

Solid GRP just holds better - but has other drawbacks I guess.

I am no expert - just guessing and quoting what I have heard.....
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Old 22-08-2017, 14:06   #68
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Re: Solid Fiberglass Monohulls, a list

Solid decks tend to flex a bit in some large spaces , like the foredeck, but what's the harm in that?
It amazes me no one has done a grid to support solid decks in lieu of balsa core construction. It wouldnt take much, maybe just enough to support every sq ft or so. They make pans/grids for the hull floors/bottom.
With today's high strength glue type things, you could pre-make long channel or rounded channel shaped glass and just bond it on the deck underside prior to putting the deck on the hull.
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Old 22-08-2017, 14:12   #69
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Re: Solid Fiberglass Monohulls, a list

Solid fiberglass (or today, epoxy resin infused fiberglass) is heavy as hell, but very strong. However, you get very good strength and greatly reduced weight when using a core material to make up some of the thickness in the hull and coat (and infuse) that material with the resin as well.

Keeping that material density below the waterline (the density and mass caused by solid layups without core materials that are less dense than the hardened resins) keeps boats upright, but having that dense material on decks and cabin tops can lower the vessel's righting moment and makes it more susceptible to rolling because of the weight distribution then created. Ideally, all the hard layup would be in the lowest portions of the hull, at and below the waterline, therefore. That said, there are some other issues.

The hull that has solid layup on side decks will have stronger side decks, but will also be more tender at sea. This vessel will also be heavier overall, and may not make the same passage time due to total mass than another vessel with identical rigging and outfitting would make. Changing rigging or outfitting changes all this though.

The hull that is made today is made as cheaply as possible (in most production boats) and is made as a series of trays that are stacked and glued, riveted, bolted, or otherwise locked into one another, in many cases, and just is not the same level of solid construction that was common in the early days of fiberglassing.

As a result, those older vessels are outlasting the newer ones, and the public is slowly realizing that they represent a substantial deal over what is paid for today as "new" or "slightly used" in the resale market, provided the systems are in good shape or replaced with modern technology and the vessels have been refit to be in proper shape, at least to buyers who have knowledge of what a real deal is and what is purely window dressing. However, that said, many purchasers today have no idea what a sailboat is designed to do, and they are looking for more of a condo than they are a vessel to travel from A to B harbors.

The poor workmanship that has been foisted on the public over the years in some vessels, however, has really generated a problem for the modern potential sailor (and even power boaters, for that matter) because poor saturation of glass and improper layup procedures have resulted in many delaminations and thousands or even tens of thousands of boats that sit in grassy fields or among sprouted trees that have perfectly good hulls, but suffer from some other issue that could have been resolved for very little effort while the boat was new. Today, that issue has proceeded to the point that the vessel is worth more as scrap material than it can ever be on the water again, and I see that as a real pity.

It is a good thing I no longer live in the woods, because I would today have a boatyard of derilects, each being salvaged for the many tiny parts on board, in the attempt to recycle as much of each one as physically possible before they were committed to Davy Jones as reefs (I still believe that there is a valid method of stripping fuel systems and other soft parts from these wrecks and sinking them to rebuild reefs and recreational fishing areas that have been damaged by all manner of issues, and that these actions are less damaging that sinking an aircraft carrier in like manner in the attempt to do the same).

The chopper boats that make up the mass of the 1970's and especially 1980s boat markets are often at fault for the reputation of poor glassing processes because of the varied quality that this form of fabrication can produce, but I don't count those as "hand layup" vessels. Still, you have to learn to interpret what the salesman is saying because unless you physically LOOK, you often cannot tell which method was used. If they used a core, the issue is even more substantial and problematic.
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Old 22-08-2017, 16:08   #70
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Re: Solid Fiberglass Monohulls, a list

both my current Caliber 40 and my earlier caliber 33 have solid hulls and plywood cored decks
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Old 23-08-2017, 11:53   #71
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Re: Solid Fiberglass Monohulls, a list

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Solid fiberglass (or today, epoxy resin infused fiberglass) is heavy as hell, but very strong. However, you get very good strength and greatly reduced weight when using a core material to make up some of the thickness in the hull and coat (and infuse) that material with the resin as well.

Keeping that material density below the waterline (the density and mass caused by solid layups without core materials that are less dense than the hardened resins) keeps boats upright, but having that dense material on decks and cabin tops can lower the vessel's righting moment and makes it more susceptible to rolling because of the weight distribution then created. Ideally, all the hard layup would be in the lowest portions of the hull, at and below the waterline, therefore. That said, there are some other issues.

The hull that has solid layup on side decks will have stronger side decks, but will also be more tender at sea. This vessel will also be heavier overall, and may not make the same passage time due to total mass than another vessel with identical rigging and outfitting would make. Changing rigging or outfitting changes all this though.
I disagree that a solid deck boat would be much heavier, if any at all. A cored deck has 2 skins. On my boat as an example the inner and outer skin are both 3/16" thick, sandwiching 1/2" balsa core. A solid deck need not be as thick as these 2 skins together. !/4" to 5/16" would be plenty assuming a good glass layup. It would have fiberglass beams spaced at 12" to 18". The beams do not need to be very heavy to add the required stiffness.
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Old 23-08-2017, 13:01   #72
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Re: Solid Fiberglass Monohulls, a list

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I disagree that a solid deck boat would be much heavier, if any at all. A cored deck has 2 skins. On my boat as an example the inner and outer skin are both 3/16" thick, sandwiching 1/2" balsa core. A solid deck need not be as thick as these 2 skins together. !/4" to 5/16" would be plenty assuming a good glass layup. It would have fiberglass beams spaced at 12" to 18". The beams do not need to be very heavy to add the required stiffness.
Let me rephrase a bit because you are taking today's ideas and moving them against yesterday's tech to make a point about yesterday's vessels (as I was talking about yesterday's vessels and if we made them the same way today, not the latest in vaccuum bagging tech and kevlar, carbon fiber, etc...).

The boats of solid glass layup did not have fiberglass beams under the decks. At BEST some had wood structure that was then encased in fiberglass after the decks were initially laid upon it, and the entirety was then hit with a chopper gun to make the entirety into a cohesive shell of sorts.

A boat laid up in sheets of glass, without the benefit of extra support, would have decks far more dense and heavy than a cored deck. There is no argument about that, which is part of why decks are cored today. If that were not the case, they would still be solid and boats would weigh more. There is a reason my Hunter is 7200 pounds dry weight at only 27 foot OAL. It is because so much of the hull is solid. If it were cored, you could probably cut off about 1500 pounds of weight. And I have cored decks and I believe hollow coach roof sides!

Balsa weighs very little, and so if you put balsa into a deck and displace the glass that would be in it, even if that glass was thinner, the boat is going to be lighter. Now if you instead made a tray and used glass in a grid pattern to support that deck (what is done on some boats), you are in essence creating a support grid for the deck, but it is STILL a cored deck being used because of the benefits of using core materials (inclusive of greatly reduced labor costs, a key point in the way today's boats are made). Production boats did not lay up glass that well once they went to the cheap labor forces of the 80's and the economic disaster that followed.

There are so few production boats today that use uncored hulls and/or decks that I have a problem even coming up with one as an example (and I have been looking just for your comment's sake). Everyone is using a core of some sort, and boats are lighter in part because of that. They are also faster to produce, and cost less than if they were solid.

The US regulatory agencies that mandated lower resin content aside, the cost of all that new resin in an uncored deck alone would prevent any solid decks from being made today. Then we get into the relatively unskilled labor that is so often used to fabricate production line boats (again, cost reduction), and it just was not cost effective to do what you suggest in yesterday's vessels (and we are only talking about yesterday's vessels here, who knows what someone will attempt tomorrow). If they had used epoxy back then, we would be having another conversation, but they did not. You could probably do that today with epoxy, and then you would get what you are asking for, and in that we would agree.

Now, all that said, I do agree that some support system could be fabricated to make a solid glass layup deck useful on a boat in the production lines, but you had better have some decently skilled labor for fabrication and installation of that system, a very good naval architect to ensure that the stresses on the resultant structure would not pop the hull joint apart due to the ways that the grid distributed torsional forces as the vessel twists and bends at sea, and you would need to INCREASE the cost of the vessel to accommodate the change to your new system from the cored standard that is used internationally to fabricate recreational vessels.

You also still have to add some weight above the waterline relative to the cored versions that use whatever resin you are currently using, and your boat will be more tender, which is not necessarily horrible considering so many today are condos at the dock rather than something anyone gets offshore with.

There are no free lunches, and a solid deck will increase density of the deck material. If you want to be able to walk on it and allow it to accept impacts and point loads without cracking, it is also going to have to be thick and stiff enough to the point that it weighs more than two thin skins and some balsa wood. The resulting deck won't necessarily deflect in compression, but it will crack with impacts if it is not thick enough, and that will make it heavier than a cored deck of balsa and two thin skins, in my humble opinion (for whatever that is worth).
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Old 23-08-2017, 13:04   #73
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Re: Solid Fiberglass Monohulls, a list

We also agree that the beams don't need to be heavy, but they still need to occupy space internally, and so the interior must be designed around them. Additionally, they need to be able to deal with the compression, torsion, and panting stresses of a beam or quarter sea, so again, the architect is going to be involved, along with the associated costs. The price goes up, the vessel sells fewer units, the business suffers, the vessel is discarded from the lines.
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Old 23-08-2017, 14:01   #74
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Re: Solid Fiberglass Monohulls, a list

My Contest 32CS ketch is solid glass hull and decks. I do not know if it's the same with other Conyplex/Contest boats.
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