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Custom Boat Shafting and Machine Shop


We feature Aqualoy marine shafting (AQ19 & AQ22) ranging from ¾" to 8" with lengths up to 28' machined to meet any required specifications.

AQ19 (standard boat shaft) always available with quick turn-around time in the machine shop.

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 Available Sizes
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. They are available up to 12 inches (304.8 mm) in diameter and up to 38 feet (11.59 m) in length.

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AQ22 (high-strength boat shaft) is stocked locally and readily available for special order.

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 Available Sizes
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. 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.

Aqualoy 22 High Strength
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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Kruger & Sons

4463 26th Ave W.
Seattle, WA 98199
+1 (206) 283-7707
+1 (800) 762-7767
+1 (206) 283-0586 - FAX


Monday - Friday
8:00 AM - 4:30 PM PST

Saturday-Sunday: Closed

Seattle Propeller Service