hull strengths 1 stronger than the other

[Randall]

I have searched the site for this specific topic and I cant seem to find what I am looking for. The question is what makes a hull stronger than another hull made today. You hear the term the hull is not strong it flexes. This boat is not a blue water cruiser the hull is not strong enough. If you compared a non blue water boat say a Catalina hunter beneteau and a blue water boat say a island packet what makes these two boats hull so different. Or are all hulls pretty much the same today but it’s the equipment in the boat that makes the difference. Looking for simple actual information thanks.

[forsailbyowner]

The actual thickness of the glass combined with the internal structures that makeup the framing, bulkheads, bunks etc... along with coring determine the stiffness of a hull. generally a stiffer boat has more bulkheads and more small spaces than open airy interiors which lack sufficient rigidity to control flex.

[jzk]

I don't see a Catalina or Beneteau really having a hull failure, but an unprotected spade rudder could be a big problem.

[dacust]

Next time you're at a boat show, rap on the hulls at various points with your knuckles. Then decide for yourself if they are all made about the same. There are big differences between different brands.

As forsailbyowner points out, though, this is only one indication of strength.

-dan

[s/v Beth]

Lets just not get into it, because some of us don't see IP as true bluewater either. But I'm not here to bait, just say their are areas of grey in the bluewater boat business...
I would look at those boats that have survived storms well- and have not broken- as being the "strongest". It is usually the combination of sound design with robust production and a careful experienced sailor that does the best. I will let others judge on what boats are missing what. Hull strength is only one factor (in that category IP does shine)
Sorry for no facts/figures. I do not want to flame or start a war. All of us have our pet boats. But you can start your education by looking at what other people are sailing and what they say about their boat in the conditions you wish to sail in.
BTW- I just bought a Valiant.

[Celestialsailor]

A strong hull does not mean that break downs will not occur. There are sails, rigging, engine, running gear, running rigging and so on and on and on. Any one of those could create a disaster in the right conditions. Rarely is a hull so flimsy, it will not ride out a blow or two. as I found out, the thousands of pieces of harware can give up the ghost when it damn well pleases.
We were heading into a tropical depresion last July in my Ingrid 38. The boat was handling 35 kts of wind and 15 ft seas. What I did not expect was the boom ripping out of the mast. Maybe a Clipper 21 would not have had that problem. Many forces work many different ways on many different sizes and designs of vessels. Like Captain Ron said..." If anything is going to happen to you...it's going to happen to you out there.

[SilentOption]

I agree with Celestial. If the hull is built so strong that it will not give under any condition the shock will be transferred else where like the rigging, the joinery or the humans standing on deck. Strong, heavy and rigid doesn't mean no shock or pounding and it doesn't guarantee a soft ride..
You can have the strongest hull afloat but running hard in rough seas will have some penalty eventually. Anyone here familiar with sportfishing boats? The Ocean earned the nickname Flexible Flyer because it was built light to go fast. Unfortunately the boats didn't fare so well in rough water. Things came apart. Hatteras on the other hand built heavy and could take a severe pounding. The boats could come down hard off a huge wave and keep on going. Unfortunately the same couldn't be said passengers.

[noelex 77]

The hull layup, over most of the structure, for blue water boats is typically only marginally stronger than a normal production boat, but that doesn’t mean there are not big differences. Keel attachment, rudder strength chainplate strength etc are all areas where the fundamental structure will be better. This means that the boat will stand a better chance of performing trouble free in the harsh blue water environment.
One criticism labeled at blue water fiberglass boats is it is impossible to make a fiberglass structure that is very puncture resistant, the material is just too brittle. Some designers like Amel overcome this problem by using watertight bulkheads to divide the boat into different areas, but most ignore the consequences of a collision with a container or stranding on a reef.
Metal boats are much better in this regard. Think of an aluminium can although incredibly thin and not very strong it can be crushed to an unrecognizable shape and maintain its water tight integrity .

[noelex 77]

Originally Posted by newt

Lets just not get into it, because some of us don't see IP as true bluewater either.

I have always admired IP, but have never seen one in person. (there don't see to be many in the Med or Australia). I would be interested in your thoughts. Maybe start a new thread, but please dont let it deteriorate into a slanging match. My view is critism of a boat or piece of equipment is OK althogh we may disagree and not like it if we own said equipment.

[Talbot]

Originally Posted by jzk

I don't see a Catalina or Beneteau really having a hull failure.

Cant speak for Catalinas, but there have been a number of incidents where the mass produced flat bottomed boats in heavy weather have crashed down so hard that the furniture inside the boat has started to break up. This indicates that the hull is mite to flexible for my tastes.

for GRP boats, puncture resistance is better in those boats that have a solid hull rather than a cored structure. They are however, heavier, so not so fast. (I would rather have the solid structure)

[Randall]

great lots of info thanks

[David M]

Flexing is not necessarily a bad thing. Even the largest ships flex. On ships in heavy seas you can see the ship flex and feel it resonate under your feet. Some things need to flex in order to not break, like aircraft wings.

[s/v Beth]

PM sent to noelex 77. I have my opinion, but you should form yours from as many facts as you can.

[Talbot]

Originally Posted by David M

Flexing is not necessarily a bad thing. Even the largest ships flex.

Dont disagree, in fact have been in a ship that had expansion joints in the superstructure to cope with that flexing.

However, the flexing should not break up the internal fittings. If it does, it is either flexing too much, or the internal fittings were badly designed.

[noelex 77]

Originally Posted by Talbot

If it does, it is either flexing too much, or the internal fittings were badly designed.

I think a lot of the problem comes from attaching bulkheads with tabs. This was pioneered, I believe, by Beneteau and has since been adopted by most similar production boat builders. It is a common problem area when these boats have been exposed to rough conditions. Companies like HR or most older fiberglass cruising boats attach there bulkheads much more securely and dont usally give problems.