.
Our site needs your help!
Site categories

Characteristics of Different Types of Construction Materials

Join Our Telegram (Seaman Community)

Explore sailboat materials with our comprehensive guide covering fiberglass, wood, composites, steel, aluminum, and ferrocement. Learn about the strengths, considerations, and suitability of each material to make an informed choice for your sailboat.

СодержаниеСвернуть

One of the major issues in the decision process is the type of construction material for the hull and deck. The major factors in selecting material are cost, maintenance, performance, and use. If you can eliminate several materials or focus on one type, it will immediately simplify your selection process and reduce the number of boats you must consider. While most buyers are now interested in fiberglass boats, the other available materials have characteristics that may be more suited to your specific needs. The following section discusses the primary characteristics of each type of construction material.

Fiberglass

Fiberglass is relatively easy to work and to mold into many different shapes. Consequently, it imposes few restrictions on the shape of the hull and keel. It tends to be a strong material and has a good strength to weight ratio. If properly laid, fiberglass is almost maintenance-free when compared with other materials. Normal wear and tear and aging are usually manifested only in cosmetic deterioration. Small repairs are relatively easy and can be learned by the amateur. Fiberglass is an expensive material, but cost is offset to a large degree by the efficiencies of mass production.

Wood

Most of the older classic designs were made in wood. Now wood is commonly used for the interiors and joiner work in most boats, whatever their hull-deck construction.

Wood is an easy-to-work material using traditional woodworking tools (as well as modern electric tools) and skills. If you already have experience with wood construction through house remodeling, cabinetmaking, or furniture making, you are well on your way to being able to work on a wooden boat.

For many people, wood is aesthetically pleasing and has a warmer and more traditional appearance.

Unless the boat is constructed of an epoxy laminate, the wooden boat will generally be heavier than a comparable fiberglass or aluminum boat. There is often less room inside a boat of traditional wood construction because of the space taken up by stringers, ribs, and bulkheads, and because the older designs in wood used less freeboard and lower cabin trunks. Standing headroom in older designs was rare under thirty feet LOA (length overall), and fewer bunks were generally included.

Wood requires more maintenance than most other construction materials. Major concerns are:

  • rot,
  • surface finish,
  • sealing of fastenings,
  • deck leaks,
  • hull leaks,
  • caulking,
  • and worms.

A wooden boat has to be constantly maintained to prevent major problems. If it is not taken care of for a year or more, or tightly closed up without proper ventilation, serious problems can be expected.

Brown wooden boat on the water
Wooden boat
Source: unsplash.com

The cost of a wooden boat in less than mint condition will be substantially discounted. The price of a new wooden boat using traditional labor-intensive construction methods and top-grade wood will be comparable to or higher than the price of a new boat constructed of other materials. Financing and insurance will be harder to secure for any boat with a wooden hull.

Composites

“Composite” construction refers to the combination of several materials and techniques in a single hull or deck. The use of composites has recently increased dramatically, with the major initiative for experimentation in this area coming from the racing fraternity. The early use of composites was in the protection of wooden hulls, but they are now more commonly used to lower overall weight and increase weight-to-strength ratios. The more common composite construction techniques include:

  • fiberglass sheathing of wooden hulls and/or decks;
  • epoxy-saturated wood;
  • and coring of fiberglass decks and hulls with plywood, balsa, or foam.

Fiberglass sheathing of traditional wooden hulls, decks, and cabin trunks eliminates the need for caulking and minimizes some of the potential leaks of wood construction. It almost completely eliminates the chance of worm damage to the hull. It also provides additional strength to both the hull and the deck, but at the cost of a large increase in the boat’s displacement. Inspection for rot in the wood layers is much more difficult with fiberglass sheathing, as are repairs if a problem is found.

The use of epoxy-saturated wood has increased in the racing community considerably within the past several years. This technique is infrequently used for custom-built cruising or production boats. It produces a light boat with high strength. Unfortunately, this method is still considered “high-tech” and is relatively expensive. Because of its comparative rarity and the layered characteristics of the construction technique, repairs may be difficult for the amateur.

Read also: How to Choose the Perfect Sailboat: Tips on Selection, Ownership, and Alternatives

The technique of cored fiberglass is increasingly being used in all classes of new construction. Initially, marine plywood and balsa were usually used for the cores. Balsa and foam cores (Klegecell, Nomex, Airex, etc.) now predominate. Cores were long used in decks to reduce weight and increase stiffness. They have now become popular in hulls for the same purposes. Boat weight directly translates into cost, and manufacturers are desperately trying to hold the line on price increases while maintaining performance standards. A side benefit of this construction method is the heat and sound insulation provided by the cored hull and deck.

Steel

Steel-hulled and decked boats are immensely strong, providing a large safety margin in survival storms or against being holed in a collision or grounding. Few production boats are built with steel. Steel boats are usually custom-built boats or home built to purchased plans. After about fifty feet LOA, steel boats are more competitive in the weight and cost categories.

Steel construction, particularly in boats under fifty feet LOA, tends to be heavy, with high displacement-length ratios. This is because of the high weight and minimum plate thickness requirements of steel construction. Because of construction limitations and cost considerations, steel boats, particularly in the smaller designs, usually have full keels and are hard-chined (have sharp angles on the bottom where the plates meet rather than a smooth, continuous curve).

Yacht on the sea
Harmony III Yacht
Source: unsplash.com

The steel boat, unless properly insulated, will have heavy condensation and will be noisy. Steel requires meticulous rust and galvanic protection (galvanic corrosion occurs when an electric current is created by immersing two dissimilar metals in water, particularly salt water. The metal with the higher electrical potential gives off a current that causes it to lose its molecular structure, corrode, and eventually dissolve or disappear completely). Sophisticated compass correction is also usually required on the steel boat.

Aluminum

Aluminum produces a very light but strong hull with a high strength to weight ratio. As with steel, great care must be taken to protect it from oxidation and galvanic corrosion.

Because of the high cost of marine-grade aluminum alloys and the sophisticated welding and plate-bending techniques required during construction, aluminum is a very expensive material. Although it is rarely used in production boats, aluminum is more common in custom work.

Ferrocement

A ferrocement boat is usually built from purchased plans by the home builder or as a custom design. Ferrocement boats usually have full keels and are very heavy, with high displacement-length ratios. In larger boats, however, the weight ratio becomes more comparable to other construction materials. As a rule, ferrocement hulls have a low weight to strength ratio.

The major cost savings (usually about 10 to 15 percent) with the ferrocement boat are in the hull material and in labor if it is home built. The deck and deckhouse are usually made of wood or wood with fiberglass sheathing. Construction costs following the hull lay-up are similar to those for wood and/or fiberglass hulls, assuming comparable quality in the rigging, engine, hardware, and other features.

During a survey it is very difficult to ascertain the quality control used in the lay-up of the hull, unless there are obvious problem areas. The hull must use sufficient reinforcing rod (this is what gives it its strength), which must be rust-proofed. The cement plaster must be mixed correctly and have no voids. Voids or inadequate rust-proofing can result in corrosion, including galvanic corrosion, of the reinforcing rods, threatening the hull’s integrity.

The resale value of ferrocement boats is low, in some instances only 50 percent of comparable boats constructed of other materials. This is because of the difficulty of ascertaining the hull’s integrity in a survey and a history of poor quality control in the hull lay-up by many amateur home builders. Both of these factors have created a negative reputation for ferrocement hull boats.

Author
Author photo - Olga Nesvetailova
Freelancer
Literature
  1. Cruising World, Subscription Service Dept., P. O. Box 953, Farmingdale, NY 11737.
  2. Motor Boating & Sailing, P. O. Box 10075, Des Moines, IA 50350.
  3. Multi-hulls, 421 Hancock St., N. Quincy, MA 02171-9981.
  4. Nautical Quarterly, 373 Park Avenue South, New York, NY 10016.
  5. Sail Magazine, P. O. Box 10210, Des Moines, IA 50336.
  6. Sailing, P. O. Box 248, Port Washington, WI 53704.
  7. Small Boat Journal, P. O. Box 400, Bennington, VT 05201.
  8. Soundings, Soundings Publications, Inc., Pratt Street, Essex, CT 06426.
  9. The Practical Sailor, Subscription Dept., P. O. Box 971, Farmingdale, NY 11737.
  10. Wooden Boat, Subscription Dept., P. O. Box 956, Farming-dale, NY 11737.
  11. Yacht Racing/Cruising, North American Building, 401 North Broad Street, Philadelphia, PA 19108.
  12. Yachting, P. O. Box 2704, Boulder, CO 80321.
  13. Beiser, Arthur. The Proper Yacht, 2nd ed. Camden, Maine: International Publishing Co., 1978.
  14. Chapman, Charles F. Piloting, Seamanship and Small Boat Handling, 56th ed. New York: Hearst Marine Books, 1983.
  15. Coles, Adlard. Heavy Weather Sailing, 3rd rev. ed. Clinton Corners, N.Y.: John De Graff, Inc., 1981.
  16. Pardey, Lin and Larry. Cruising in Seraffyn and Seraffyn’s Mediterranean Adventure (W. W. Norton, 1981).
  17. Roth, Hal. After 50 000 Miles (W. W. Norton, 1977) and Two Against Cape Horn (W. W. Norton, 1968).
  18. Royce, Patrick M. Royce’s Sailing Illustrated, 8th ed. Ventura, Calif.: Western Marine Enterprises, Inc., 1979.
  19. Kinney, Francis S. Skene’s Elements of Yacht Design, 8th ed. New York: Dodd, Mead, 1981.
  20. Street, Donald M., Jr. The Ocean Sailing Yacht, Vols. I and II. New York: W. W. Norton, 1973, 1978.

Footnotes
Sea-Man

Did you find mistake? Highlight and press CTRL+Enter

Июнь, 18, 2024 71 0
Add a comment


Notes
Text copied