Marine ventilation parts need matching duct size and collector-box geometry, not just a similar louver shape. Attwood's 1494 and 1495 vent series use different collector arrangements, while the modular 1438F1 is a centre section rather than a full vent kit. Use the original MPN and duct diameter to identify the replacement.
Identify the part before changing a duct
The louvered opening admits or exhausts air. Its shape and mounting hole must match the hull.
A shaped fitting connects the vent to one or two ventilation ducts of the specified diameter.
An inline 12V fan moves air through appropriate ventilation ducting. Match its diameter and electrical rating.
Attwood vent and blower identification by MPN
The 1494A1/1494A5 vent variants are associated with 1341 or 1342 collector boxes; 1495-1 uses 1345; and 1438F1 belongs with the 1348 modular system.
| Part number | Component | Duct diameter | Matching system / specification |
|---|---|---|---|
| 1494A1 | Black louvered vent | 3 or 4 in | 1341 for two 3-in ducts; 1342 for one 4-in duct |
| 1494A5 | Black louvered vent | 3 or 4 in | 1341 for two 3-in ducts; 1342 for one 4-in duct |
| 1495-1 | Off-white louvered vent | 3 in | 1345 collector for two 3-in ducts |
| 1438F1 | White modular centre vent | 4 in | 1348 collector; 1439F1 end pieces for complete modular vent |
| 1733-4 | Turbo 3000 inline blower | 3 in | 12 V DC; 120 CFM open flow at nominal 12 V |
| 1749-4 | Turbo 4000 inline blower | 4 in | 12 V DC; 200 CFM open flow at nominal 12 V |
Collector boxes, modular end sections, hose and installation hardware are separate components unless a specific product's listed package contents say otherwise.
Reading Turbo 3000 and Turbo 4000 blower ratings
Attwood lists 1733-4 as a three-inch Turbo 3000 and 1749-4 as a four-inch Turbo 4000, both water-resistant 12V models. Their manufacturer ratings change with the test voltage and duct conditions.
Attwood's reference system with three feet of duct, a 90-degree bend, a collector and louver produces lower airflow than an unobstructed blower. Actual performance depends on the complete installation. Match duct size before choosing the blower.
Before ordering a replacement
Measure the existing hose inside diameter, the hull cutout and the original collector-box connections. Check any loose or missing modular end pieces and confirm the 12V blower voltage and fuse arrangement.
Do not treat a passive vent as a powered blower replacement. Check the vessel's ventilation requirements before substituting or changing parts.
Find the matching Attwood part number
Open each MPN to check the current listing and availability.
Attwood 1494A1
Louvered vent from the 1494 family. Compare the mounting opening and the original 1341/1342 collector box.
Check product details and availability
Attwood 1494A5
Compare with 1494A1: manufacturer catalogue lists these in the same vent style, with different package identifiers.
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Attwood 1495-1
Identify the off-white 1495 louver and the matching two-duct 1345 collector, not a 1341 box.
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Attwood 1438F1
Identify this as the 1438F1 modular centre section. A finished assembly also uses matching end sections.
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Attwood 1733-4
Check the 3-inch Turbo 3000 housing, 12V rating and 1733-4 package number.
Check product details and availability
Attwood 1749-4
Larger 4-inch Turbo 4000 blower, not the 3-inch model despite the similar white housing.
Check product details and availabilityOther Attwood bilge equipment
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