Irwin 37
Built 1971–1982 by Irwin Yachts
About the Irwin 37
Researched from public sources for this model. Any individual boat may have been modified or repowered — confirm before relying on any figure.
- Built
- 1971–1982
- Builder
- Irwin Yachts
- Designer
- Ted Irwin
- Length
- 37 ft
- Waterline
- 30 ft
- Beam
- 11.5 ft
- Hull / keel
- fin keel
- Rig
- sloop
- Propulsion
- inboard
- Stern thruster
- none
Sources disagree on engines, displacement, ballast, draft, fuel tank, water tank, number built — left blank rather than guessed.
Center-cockpit aft-cabin cruiser built in versions 37-1 through 37-5 (Mark V was the last, 1982); roughly 600 sold. Sloop standard, cutter or ketch optional; a bowsprit was added from 1976 (37-2). Keel options: deep fixed, shoal fixed, and keel/centerboard (4.0 ft board up). Displacement, ballast, draft and tank sizes vary by version and source, so they are left null (see disputed). The original engine was the Perkins 4-107; later boats have the 4-108. LOA, LWL and beam agree across sources. Engine access through the walk-through passage is praised. Hull laminate type (solid vs cored) not stated in sources read.
Known problems for this model
-
Gate valves on through-hulls plumbing
Practical Sailor found gate valves fitted on the through-hulls of the boats it examined, which it considers a serious shortcoming; replace with proper seacocks.practical-sailor.com
-
Bottom hollows and print-through hull
Some later hulls showed deep dished areas in the bottom, blamed on hulls being cradled before fully cured; earlier hulls often show roving print-through in the topsides gelcoat.practical-sailor.com
-
Gelcoat defects and crazing deck
The model had a record of warranty claims for thin, thick, discolored or crazed gelcoat, and the diamond-pattern nonskid used into the early 1980s is hard to repair invisibly. The fiberglass bowsprit could flex and craze the gelcoat when the rig was tensioned.practical-sailor.com
-
Screwed hull-to-deck joint deck
The hull and deck flanges are bonded with polyester slurry and held by self-tapping stainless screws at roughly 6-inch spacing rather than through-bolts, so check the joint for leaks and movement.practical-sailor.com
-
Chainplates glassed into topsides rigging
Chainplates are stainless webs laminated into the hull sides during layup, so they cannot be pulled for inspection like bolted plates; any corrosion or leakage there is hard to assess.practical-sailor.com
1 more
-
Heavy helm steering
Owners report a stiff, attention-hungry helm under sail and power, which the reviewer attributes to an unbalanced rudder, a small wheel and a long steering run around the aft cabin.practical-sailor.com
Engines & parts
Perkins 4.108 parts: good
Factory optional engine — you entered “Perkins 4-108”
Out of production but very well supported. Trans Atlantic Diesels (TAD) sells complete aftermarket rebuild kits (pistons, liners, rings, bearings, gaskets, valves, guides, seals), heads, blocks, crankshafts, genuine Perkins camshafts, rebuilt injection pumps and injectors, Jabsco/Sherwood raw water pumps, heat exchangers, starters, alternators and elbows, plus rebuilt exchange engines. The Westerbeke 4-107/4-108 family and some industrial engines share the base design.
Parts sources: Trans Atlantic Diesels (TAD), Foley Engines
Common problems (1)
-
Rear main (crankshaft) seal leak engine
The original rope-type rear seal is notorious for leaking and often starts leaking again a few hundred hours after replacement; Foley sells a nylon/Teflon replacement seal meant to cure it, and owners check the crankshaft sealing surface for pitting.foleyengines.com · boatdesign.net · forums.sailinganarchy.com
Model sources (6)
sailboatdata.com · sailboatdata.com · sailboatdata.com · practical-sailor.com · sailrite-saildata.nyc3.digitaloceanspaces.com · goodoldboat.com
Other Irwin models
- Irwin 10/4 1975–1982
- Irwin 30 Citation 1977–?
Researched from public sources. Spotted an error? The sources are listed above — tell us what they got wrong.