Originally Posted by clockwork orange
While I know this thread is about monohulls it may be useful for people to understand that a boat does not really need to be heavy displacement to be built without a core, there are a lot of boats with solid glass hulls, i have owned two multihulls with solid glass hulls and cored decks, a 31 ft Gemini
at 7000lbs and a Macgregor 36 at just 4000lbs. The key is to understand where you can and can not build without core. When i hear people claim ridiculous hull thicknesses i cant help but think either its either BS or its a poorly engineered boat built using the brute force and ignorance approach. Overbuilding just squanders payload on a cruising boat which is why you will often see heavy displacement boats that should have enough payload for everything you want to carry at DWL having their WL painted many inches higher. A well engineered hull will often utilize solid glass where it makes sense, ie, below the waterline where weight is beneficial and in areas of the hull with a lot of compound curvature which allows for solid glass without ridiculous thickness but then transitions to either a core or interior structure such as ribs and or stringers in areas that are flatter such as the topsides forward. I have an old Lindenberg 26 for example which is cored (Foam) above the waterline only from the bow back to the galley
with everything else being solid glass about 1/4" thick. They could have used stringers instead of core forward had they wished but coring gives a cleaner interior and using foam was a wise choice. The decks are foam and trouble free and light where it matters especially important on a boat with high freeboard. This is a well engineered boat, unfortunately some of the build did not match up to the engineering. BTW, the hulls on the Macgregor 36 were also well engineered and only measure about 3/16 to 1/4" overall but are realativly massive everywhere they need to be at about 3/8". Any thicker would be stupid heavy for no gain. The reason you don't see many solid glass decks is mostly because there are very few parts
with compound curvature ( think eggshell) that would allow for reasonable weight and most boats can not afford the loss of headroom
that interior structure would take up.
Mate, long time ago builders dont have the knowledge and experience with the new stuff , in any case they build this boats with stupids layups and today this boats are still sailing , some are survived to reefs
, hurricanes and collisions, if a 40000 pounds boat with a insane hull ticknes make 6 or 7 knts in 15 or 20 knts of wind
sounds cool to me and is enough for cruising , and here we goo again with the assumption that heavy weight boats are slow by nature, some yes and some not, we cross the pond 25 years ago in a 62 ft Steel cutter
with a weight of 40 tons averaging 9 knts all the way , i can agree with you that dont make any sense anymore to build thick and heavy due new building techniques , cores, exotic materials etc... you can make a light and strong boat today, from what i see this days, solid decks are timeless, same as hulls if they get proper maintenance
, core decks are something in the maintenance
list same as hulls with core, something to wacht and take care, solids decks have advantages and downsides, recoring a deck
is a expensive job, moisture and wet cores make the whole thing no sense, again , i will take any well made it coredeck v solid anytime, and i will take any well made it solid deck
v bad core deck anytime, time put everything in place, having owned 2 core boats in the past i swicht to a solid construction, to me the only drawback is a penalty in light airs and i made some modifications to mitigate that, light sails
, and deck gear
, and i swear that in many cases sailing alongside to other light construction boats the diference is minimal or nonexistent, ..
To be honest if thicknes is a negative aspect in boat construction , mould liners to hide and support a weak structure is a criminal offense, and we know that FG bulkheads and stringers is endangered... you can get a wonderful foam core deck resting in a weak thin mould lined hull with bulkheads resting in plastic slots , heeee, hell yes,
Thick hulls and decks make a strong structure if is supported by proper stringers and bulkheads , weight is a isue , but the days of spruce masts and cotton sails
are over, my hull is 36 years old, no delamination
, moisture, oil
canning or any other kind of BS , its surveyed 2 times since im the owner, and in both reports the result is satisfactory, my 2 cents that many 36 years old core hulls and decks cant say the same?
Im not a core hater , no, in fact my next boat is going to be cored,but i know this will be a expensive proposition, few brands made well designed and well enginered core boats, the rest is just playing nuts with customers, the saying about in the past builders dont know much about FG and lay FG like demons thinking how many layers need the hull to be strong enough can be twisted as today many builders are scrachting their brains thinking how thin and light the hull can be to be strong enough, hehe.
The troglodites from the past made thick and heavy hulls , and strong structures , they are still strong this days and still sailing, some yuppies in elegants offices are thinking in how to save costs and make more profit more profit at the expense of safety
and proper build techniques .
Saying that both metods of construction are well suited in some circurmstances , others not.