Custom Boat Shafting
Quality Propeller Shafting That Lasts
If your shaft is repairable, we have the capabilities to straighten shafting up to 12” diameter steel, and 10” diameter stainless steel. If we are not able to fix your current shaft, we offer the following new shafting replacements:
We feature precision finished stainless steel Aqualoy propeller shafting in four different grades: AQ17, AQ19, AQ22 and AQ22 High Strength.
Most crew boats in this country that service offshore drilling rigs are equipped with Aqualoy 17 shafts. So are shrimp trawlers…as well as many pilot boats, patrol boats and numerous other types of work craft. The reason for such wide acceptance in rugged service is simple: Aqualoy 17 shafts have proven themselves to have the finest combination of strength and toughness of any shafting material currently in use. When installed as original equipment, 17 shafts can be used in smaller diameters because of their extra strength. This means lighter struts and smaller bearings for less weight, less underwater drag and lower cost.
Aqualoy 17 is a precipitation hardening stainless steel, which has the highest strength, and hardness of all stainless steel boat shafting alloys over 2 inches in diameter. The composition of Aqualoy 17 has been carefully balanced to offer the maximum corrosion resistance possible in a heat treatable stainless steel. Corrosion resistance in seawater will approach type 304 but will be less than 19.
Although 17 has been used successfully for years it is more prone to pitting corrosion than the other marine alloys. Due to its composition the Aqualoy 17 is more prone to pitting and crevice corrosion than either Aqualoy 19 or 22. If the intended service conditions make the shaft vulnerable to either pitting or crevice corrosion we strongly recommend considering either the Aqualoy 19 or 22 products. Use of sacrificial anodes and elimination of stagnant water conditions have proven successful in limiting corrosion failures in this grade. We will provide Aqualoy 17 if specified by the customer but will not entertain claims for pitting or crevice corrosion since Aqualoy 17 is our least corrosion resistant offering.
Aqualoy 17 Available Sizes-
Aqualoy 17 boat shafting is produced in sizes up to 12 inches (304.8 mm) in diameter and up to 38 feet (11.59 m) in length. Aqualoy 17 boat shafting is available by special order.
Aqualoy 19 shafts have proven to be successful in several types of boats including sport fishing, and other pleasure crafts, as well as workboats where improved corrosion resistance is desired.
Aqualoy 19 boat shafting is a chromium-nickel stainless steel that is fully austenitic, nonmagnetic, and strengthened by a nitrogen addition. Corrosion resistance is superior to type 304 and better than Aqualoy 17 shafting. However, like type 304, Aqualoy 19 is susceptible to crevice attack when allowed to remain idle for prolonged periods in salt or brackish water. All shafts should have proper cathodic protection against corrosion. Navy Grade zinc anodes, sufficient in number and properly installed, usually provide satisfactory protection.
Aqualoy 19 has also proven itself in demanding service on shrimpers, crabbers, scallopers, and other fishing boats as well as on pleasure boats. Aqualoy 19 provides superior toughness and strength, and Aqualoy 19 shafts are competitive with most carbon steel shafts since the latter are fitted with sleeves and are frequently covered with fiberglass. With 19, there is no need for such sleeves or fiberglass, and smaller bearings and stuffing boxes can be used, resulting in lower overall cost.
Aqualoy 19 boat shafts are manufactured to meet the straightness requirements of Federal Specifications QQ-N-281 and QQ-N-286, and American Boat and Yacht Council* P-6, unless otherwise noted.
Aqualoy 19 Available Sizes-
We stock Aqualoy 19 in sizes up to 5” in diameter and 30ft. However, They are available up to 12 inches (304.8 mm) in diameter and up to 38 feet (11.59 m) in length for special order.
AQ22 & AQ22 High-Strength
Aqualoy 22 provides the best combination of corrosion resistance and strength for marine applications for 2” diameter and under. It is ideal for pleasure boats, considering that these boats spend much of their time docked where corrosion factors may be highest.
Aqualoy 22 has corrosion resistance better than any other boat shafting material, even better than most high-nickel alloys. Aqualoy 22 boat shafting provides yield strength in torsion up to 3.5 times that of most boat shafts now used, plus excellent toughness. Special processing controls provide consistent, high-quality 22 boat shafts that are precision straightened, centerless ground and polished to exacting marine tolerances. Aqualoy 22 is an austenitic alloy and is non-magnetic.
Superior Corrosion Resistance
Aqualoy 22 provides outstanding corrosion resistance. For example, in quiet seawater tests, Aqualoy 22 proved superior to type 316 stainless steel, long considered the standard for corrosion resistance in marine environments. After immersion for nine months, both alloys were covered with barnacles and other marine organisms. After cleaning, the 22 boat shaft was found totally unaffected, while type 316 exposed similarly suffered random pitting and crevice corrosion. Results of laboratory tests also demonstrate 22’s superior resistance to different types of corrosion. One such test involved a 50-hour exposure in an acidified 10% ferric chloride solution. Finally, an 18-month test in actual seawater was conducted comparing 22 with Alloy 400 (Ni-Cu). Results showed that Aqualoy 22 was superior. Even though 22 is so highly resistant to corrosion, cathodic protection is recommended to avoid galvanic corrosion in salt and brackish water. Navy Grade zinc anodes, sufficient in number and properly installed, usually provide satisfactory protection.
Aqualoy 22 boat shafts are centerless ground and polished and precision straightened to meet the straightness requirements of Federal Specifications QQ-N-281, QQ-N-286 and ABYC*-P-6
Aqualoy 22 Available Sizes – Available by special order only.
22 shafts are available up to 12 inches (304.8 mm) in diameter and up to 35 feet in length. Longer lengths are available by special inquiry.
AQ 22 High Strength- Available by special order only.
Aqualoy 22 High Strength provides the same corrosion resistance as the 22 but also offers the strength of the 17 in 2-1/4 inches through 6 inches in diameter. It is ideal for those vessels requiring higher strength shafts while maintaining the highest possible corrosion resistance available. Aqualoy 22 High Strength is an austenitic alloy and is non-magnetic.
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