Fiberglass vs Steel Hull they both claim the best

Steel and salt water just don't play well together. You go with steel when you need strength such as a commercial vessel or a large yacht where fiberglass doesn't have enough strength. As far as maintenance is concerned, the difference is between waxing vs; painting and welding. In the middle of the two is aluminum.

The manufacturers claim modern coatings cut down a whole lot on maintenance of steel. I'm still not sure it makes sense for yachts much under 100'. I was reading through a random selection of hyperlinks and came to an article saying the best hull material for yachts might be monel or titanium. I shudder to think what a titanium hull would cost but it would probably be something you grand kids could use.

Not much difference in costs for a large yacht on an annual basis when real maintenance is performed rather than just waiting for problems to show up.

If you are on fire, steel is a lot better.

This question will always yield a long list of opinions, ideas, facts, and preferences. It will give you about the same about of certainty if you asked "which is better; mono or multi hull" in a sailing specific forum.

Each have their respective pros and cons.

I am an emphatic believer in quality built steel hulls. Damage due to fires, groundings, bumps in the night, and operator errors are far less likely on steel yachts. Steel trawlers usually have hull forms and displacement that provide greater stability without the need for active stabilization systems.

With hulls that are built with treated steel and proper prime and paint jobs, the maintenance should be easy and relatively insignificant, especially when compared to the haul-outs or haul-ups required from hitting docks, pilings, submerged objects, rocks, other boats, or "buoys." Yep, no delamination or wet cores here.

I would feel better about having a steel boat sit unattended for 6 months than most fiberglass boats. Superficial corrosion is an easy clean-up job and is usually only cosmetic in nature.

Ask a steel trawler owner if they would go fiberglass and I think you'll find an almost 100% consensus for a repeat steel yacht.

Judy Waldman

Materials

For Displacement hull weight is less of an issue so favor tips for steel in larger yachts.

Fiberglass is stronger than steel - sorry. Steel however is stiffer (higher modulus) than fiberglass. Solid Fiberglass while heavy has excellent damage tolerance and superior weatheribility to Steel, especially in Salt Water. Just ask the "Blow Boaters".

In a big fire - no matter what - you are in big trouble. One burns to the water line, the other the plates buckle and you sink. (Aluminum melts to the water line). The important issue here is detection time, decision time and abandon ship time....

As a cajun friend of mine once said " You know what we call a steel box in a fire? - A coon-ass microwave."

I'm with Judy. Part of a listing on a steel trawler (and that's the rub--steel has it's place here in LRCs, while 'glass makes more sense for fast fish boats and motoryachts) that I wrote years ago:


WHY STEEL?

All Real Ships including “Kellikins” have been built in steel due to a simple premise: Steel is the safest material for cruising and passagemaking. With it’s greater yield strength, and much higher ultimate strength ( simply put, how strong a material is before it bends and then finally breaks ) than aluminum or fiberglass, this steel hull will survive severe impacts, whehter they be against a semi-submerged shipping container or a coral reef. In addition, the integral fuel & water tanks create a double bottom over a good portion of the submerged surface.

What about rust? Like all Real Ships, the steel is treated by inorganic zinc primers and fairing prior to epoxy and polyurethane top coats. These paint jobs last! And, with the fully-faired hull, she looks like a fiberglass boat.

Though quite rare, a fire at sea is always a possibility. While steel begins to melt at 2800F, aluminum is next at 1220F, and fiberglass will burn at a measly 500 degrees. Unlike fiberglass composites, vessels built of metal easily meet IMO ( creators of the SOLAS rules ) fire containment standards.

Hull-to-deck joints are welded together, going one better than the screwed & bonded procedure normally found on FRP boats. Welded decks don’t leak and there is no core to rot out or delaminate over time.Welded-on components such as chocks, cleats, and towing bits are there to stay.

Lastly, over the years, a surveyor can inspect weld integrity and plate thickness with precision using ultrasound and X-ray techniques which take the guesswork out of determining structural integrity—what you see is what you get, unlike with FRP composites.

Yeah, but a little fire in a fiberglass boat can become a big one faster than it can be detected and firefighting efforts initiated.

A well trained and properly equipped crew can contain, fight, and extinguish a massive fire on a steel vessel.

Fire on Board

If the fire is massive and I have a place to go I am getting off... While the boat may be heat and toxic smoke resistant, I am not.

Fire on Board II

Loren - interesting mix. I would have used residual structural properties measure for this. You would see Steel, Fiberglass, and wood to be quite good in a fire with aluminum pulling up the rear. Interesting thing about wood is that the char insulates and protects.

FYI - E-Glass Melts at 3630 deg F. This has the effect of making it self insulating after the surface resin burns off.

SOLAS treatment of Aluminum is as a 'special' case, as is composite construction.

As regards wood, the Spanish sailors in the Armada might take issue with your position.
As regards the high melting point of E-Glass, would the occupants of a vessel made of such a material be left with something buoyant in the aftermath of a conflagration? ("Just hang in there 'til the resin burns off".)

Whiskey Tango Foxtrot?

Ah, therein lies the rub ... ships at sea don't often provide "a place to go" when things go wrong. The modern way of looking at safety at sea is to design higher levels of damage tolerance and protection from fire so that "a place to go" doesn't have to mean abandoning the ship.

Construction and design of modern steel vessels includes ventilation systems that reduce the risk of exposure to toxic fumes, and utilize materials that produce less toxic products of combustion when they do burn.

There is no way on earth or at sea for a fiberglass boat to meet those standards of protection or fire safety. In addition, once the resin is burned from any composite material, it has no more structural value than the fabric component by itself, which is zero as far as girder strength or compressive loads are concerned.

And who cares what temperature glass melts when long before that point is reached the material has become the structural equivalent of a pillow case?

I think we are talking about Yachts, not cruise ships. Do you think the machinery spaces are A60 rated in most Yachts? I would not charaterize most Yachts as damage tolerent especially with regard to Fire.

Ventilation while removing toxic fumes adds Oxygen to the fire. Metal decking gets hot very quickly making fire fighting difficult. Heat transmission thru uninsulated bulkheads can result in auto ignition in adjacent compartments.

My point is this issue is more about proper design and construction than materials.

While I am actively involved in lightweight materials businesses, that does not always mean non-metallics.

Loren - nice mouth - really...

Pelagic,

You might want to get in touch with Wray West. He and has family ran a Cape Horn 65 for several years. Cape Horns were heavily promoted with safety in mind and stout steel construction. When he and his wife downsized, they chose a 55' Bering Yacht wanting to continue with the strength and security a steel hull offered.

The West Family Website - http://www.anjumal.com/

An additional West site - http://coastalexplorer.net/users/wraywest/blog

Both are a little overdue for an update, but still interesting reading.

"...ventilation systems that reduce the risk of exposure to toxic fumes ..."

Does not equate to supplying a fire with oxygen.

Proper design and construction is not exclusive of materials or their application within the operational envelope of the vessel their use is intended. If you don't consider the materials and their limitations you cannot claim "proper design."

I am not talking about cruise ships either, I am talking about modern concepts of marine safety and construction in all forms of vessels.

Composite materials have their place, but I personally would not select them for marine applications for other than near shore voyages within rapid rescue capability because of their inability to survive a fire that in all probability would not be life threatening on a steel vessel.

As a part time student of naval history - I had to check on the Spanish Armada reference. Interesting in that the majority of Spanish ships were converted 'Freighters'.

"Ironically not one Spanish ship was damaged by a fireship." from http://hubpages.com/hub/Parallels-Between-the-Defeat-of-the-Spanish-Armada-and-the-Battle-of-Britain

Enjoy.

If you're going to spend 6 months a year cruising, I suppose you'll be doing extensive passagemaking. In that case, steel has the advantages mentioned before:
- fire resistance
- ductility: upon contact or grounding, steel will deform a lot more before breaking than fiberglass or aluminium

Additional advantages which haven't been mentioned yet:
- you can get steel repaired almost anywhere in the world, as it is the material of choice for commercial ships.
- damages are visible, which isn't always the case with cored composite hulls.

As for longevity: when treated with a good paint system and corrosion protection (anodes / ICCP), and properly maintained, steel will easily last a lifetime. Corrosion problems occur mostly in the ballast tanks on cargo ships, which are not that common on yachts (preference for fixed ballast).

Aluminium is used a lot for superstructures (weight saving aloft, needs less corrosion protection, easier to build). Also suitable for hulls, especially where speed (read weight) is an issue.

Bruno