Mason 33
Built 1984–1989 by Ta Shing Yacht Building (Taiwan)
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About the Mason 33
Researched from public sources for this model. Any individual boat may have been modified or repowered — confirm before relying on any figure.
- Built
- 1984–1989
- Builder
- Ta Shing Yacht Building (Taiwan)
- Designer
- Al Mason
- Length
- 33.75 ft
- Waterline
- 25.42 ft
- Beam
- 10.83 ft
- Draft
- 5 ft
- Displacement
- 14,269 lb
- Ballast
- 5,320 lb
- Hull / keel
- full keel
- Rig
- sloop
- Propulsion
- inboard
- Fuel
- 35 gal
- Water
- 65 gal
- Water heater
- standard
- Number built
- 20
- Stern thruster
- not fitted
- Steering
- tiller
Tank capacities — where the figures come from
-
Fuel 35 gal
“Fuel capacity 35 gallons; One black iron fuel tank totaling 35 gallons” — brochure (hulls 1-10), mason-sailboats.org · “Total Fuel Capacity (One Tank) 30 Gal.” — builder (1982 design drawing), mason-sailboats.org · “Smaller fuel (35 gal)” — search excerpt, fairkeel.comThe factory specification sheet for hulls 1-10, issued by the builder's Dana Point dealer, gives one 35-gal black-iron tank. The designer's 1982 cabin plans show one 30-gal tank but were drawn around a Westerbeke engine; production boats had a Yanmar, so 35 is taken as built. Later hulls aren't covered.
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Water 65 gal
“Water capacity 65 gallons; Two s.s. water tanks total 65 gallons” — brochure (hulls 1-10), mason-sailboats.org · “Total Water Capacity (Two Tanks) 65 Gal.” — builder (1982 design drawing), mason-sailboats.org · “water (65 gal in two tanks)” — search excerpt, fairkeel.com · “two tanks with a combined capacity of 65 gallons” — search excerpt, listingsport.comFactory spec sheet (hulls 1-10) and the designer's cabin plan agree: two stainless tanks, 65 gal total (under the main-cabin berths).
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Holding unknown
Factory spec sheet says the manual head can be pumped overboard or into a holding tank but gives no size. One guide mentions a 20-gal shower sump, not a holding tank.
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Water heater standard
“ELECTRICAL: ... 30 amp AC shore power connection ... Hot water heater; GALLEY AND HEAD: Large double s.s. sinks with pre” — builder (hulls 1-10 (c. 1984)), mason-sailboats.orgThe Mason 33 specification sheet for hulls 1-10 (from Lemest Yacht Sales, which shares the builder's Dana Point address) lists a hot water heater and pressure hot/cold water, and marks items such as teak deck overlay and pedestal steering optional, but not the heater. Capacity and heat source not given; water 65 gal.
Tanks are often replaced or added on older boats — check the tank labels or a survey for yours.
Thrusters and steering — where this comes from
-
Bow thruster unknown
The hull 1-10 specification sheet lists equipment and one option (pedestal steering) but no thruster; it is not a full option list.
-
Stern thruster not fitted
Our earlier figure of none has no source, and nothing was found either way.
-
Steering tiller
“STEERING: Laminated teak and spruce tiller with stainless steel tiller head; Pedistal steering optional (Mason 33, Hull” — brochure (1984), mason-sailboats.orgTiller standard with pedestal wheel steering optional, according to the hull 1-10 specification sheet issued by Lemest Yacht Sales (the Dana Point dealer for PAE/Mason) and kept by the owners' site. Later hulls aren't documented.
Thrusters and steering are often replaced — check the units on your boat before ordering parts.
Sources disagree on hp (Westerbeke 27) — left blank rather than guessed.
Mason design S-116; rare (sailboatdata lists 20 built).
Engines fitted
-
Westerbeke 27 — diesel, single
standard
Practical Sailor says early boats came with a 21 hp Westerbeke (model not named). A 1985 boat is listed with its 1985-year Westerbeke 27 at 22 hp (page read), and a Boat Trader listing for another 1985 boat names a Westerbeke 27 (search excerpt). hp left null: 21 vs 22, see disputed.Sources: practical-sailor.com · rubiconyachts.com · boattrader.com
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Yanmar 3GM30F — 27 hp, diesel, single
standard
Practical Sailor says later boats have a 27 hp three-cylinder Yanmar (model not named); a 1986 boat is listed with a Yanmar 3GM30F, not stated as original. Changeover year not documented.Sources: practical-sailor.com · easternyachtsales.com · listingsport.com
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Yanmar 3YM30 — 30 hp, diesel, single
common repower
A 1985 boat repowered with a 2014 Yanmar 3YM30 (single listing).Sources: ecys.com
Boats of the same model can differ — check which engines yours actually has before ordering parts.
Generator
The hulls 1-10 specification lists shore power, batteries and the AC/DC panel; no generator.
Manuals and brochures online
- Document PAE/Mason owners site - Boats page (index of builder brochures, spec sheets and drawings per model, as PDFs) — mason-sailboats.org
- Spec sheet Mason 33 specifications (hulls 1-10) with Al Mason sail plan and cabin-plan drawings — mason-sailboats.org
- Document Mason 33 profile and interior layout drawing — mason-sailboats.org
Hosted by the builder or an owners' association; they own the copyright.
Known problems for this model
No well-sourced problem reports found yet.
Engines & parts
Yanmar 3GM / 3GM30F parts: good
Factory standard engine — you entered “Yanmar 3GM30F”
Very popular (used 3GM30Fs sell for $3,000+) and supported by a strong parts network. Cylinder head overhauls (valve seals, lapping, injector service) are a common, parts-supported repair.
Parts sources: Mack Boring & Parts (Yanmar distributor), HDI Marine (stainless exhaust elbows), Parts4Engines
Common problems (2)
-
Overheating at cruise rpm cooling
The 3GM30F has a known overheating tendency linked to its heat exchanger; owners also trace it to coked elbows, worn impellers, scaled heat exchangers or air in the raw water circuit. Some heat exchangers were replaced under warranty.forums.sailboatowners.com
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Mixing elbow corrosion exhaust
OEM elbows corrode internally and should be inspected or replaced with stainless versions before they let water into the engine.practical-sailor.com · facebook.com
Maker’s service schedule (2)
| Fuel filters & water separator | 250 hrs | “The normal replacement interval for the element is 250 hours ... Filter cleaning First time 50 hours Filter element repl” — manufacturer, c320.org |
| Air filter / intake silencer | 250 hrs | “Washing period Every 250 hours” — manufacturer, c320.org |
Service part numbers (10)
| Oil filter | Yanmar 119305-35170 Replaces 119305-35151, 119660-35150 |
“3GM30F Basic Service Kit ... 119305-35170 1 FILTER ASSY, D68XL65” — dealer, oldportmarine.com · “Maintenance kit Yanmar 2GMF, 2GM20F, 3GMF, 3GM30F ... Yanmar 119305-35170 Oil Filter” — dealer, marinedustrie.com |
| Fuel filter | Yanmar 104500-55710 | “Fuel Filter Element 1 104500-55710 / Fuel Filter O-Ring 1 24341-000440” — dealer, ellebogen.com · “3GM30F Basic Service Kit ... 104500-55710 1 ELEMENT, FUEL FILTER” — dealer, oldportmarine.com |
| Raw-water impeller Japan-built 3GM / 3GM30(F) (serial not starting with E) |
Yanmar 124223-42092 | “Impeller 1 124223-42092 / Impeller Gasket 1 124223-42110” — dealer, ellebogen.com · “3GM30F Basic Service Kit ... 124223-42092 1 IMPELLER, PUMP” — dealer, oldportmarine.com |
| Raw-water impeller European-built GM-YEU (serial starting with E) |
Yanmar 128990-42570 Replaces 128990-42200 |
“(Supersedes part number: 128990-42200) ... 3GM30-YEU, 3GM30C-YEU 3GM30F-YEU, 3GM30FC-YEU” — dealer, palmerpower.com · “It fits Yanmar 2GM20F, 2YM15, 3GM30F, 3GM30FC, 3TN30F, 3YM20, 3YM30, 3YM30AE engines. Cross Reference: 128990-42200” — dealer, deltadieselparts.com |
| Drive belt | Yanmar 25132-003700 | “Alternator Belt 1 25132-003700” — dealer, ellebogen.com · “3GM30F Basic Service Kit ... 25132-003700 1 V-BELT, A37” — dealer, oldportmarine.com |
| Drive belt | Yanmar 104511-78780 | “S/W Pump Belt 1 104511-78780” — dealer, ellebogen.com · “3GM30F Basic Service Kit ... 104511-78780 1 V-BELT, M/19” — dealer, oldportmarine.com |
| Air filter | Yanmar 128270-12540 | “Air Filter Element 1 128270-12540” — dealer, ellebogen.com · “3GM30F Basic Service Kit ... 128270-12540 1 ELEMENT, AIR CLEANER” — dealer, oldportmarine.com |
| Zinc / anode raw-water 3GM / 3GM30; also sold for the F (heat-exchanger) versions |
Yanmar 27210-200300 | “27210-200300 Yanmar Engine Zinc Anode For 2GM(D), 3GM(D), 2GM20, 3GM30” — dealer, zincsforboats.com · “It fits Yanmar 2GM, 2GM20F, 2GM15, 2GM20, 3GM30F, 3GMF, 3HMF, 3GM30H engines.” — dealer, deltadieselparts.com |
| Thermostat 3GM30F / 3GMF (fresh-water cooled) |
Yanmar 121750-49800 | “Thermostat 1 121750-49800 / Thermostat Gasket 1 129350-49541” — dealer, ellebogen.com · “Thermostat for Yanmar 2GMF, 3GMF, 3HMF, 2GM20F, 3GM30F, 3HM35F / REC121750-49800” — dealer, marineparts.eu |
| Thermostat 3GM / 3GM30 (raw-water cooled) |
Yanmar 105582-49200 | “Replaces Yanmar Marine 105582-49200 ... 1GM, 2GM, 3GM, 1GM10, 2GM20, 3GM30” — dealer, repowermarine.com · “1GM10, 2GM20 & 3GM30 Thermostat to fit raw water cooled engine versions ... equivalent to 105582-49200” — dealer, parts4engines.com |
From the engine maker’s parts lists, or two independent parts dealers. Numbers change with serial number and get superseded — check yours before ordering.
Yanmar 3YM30 / 3YM20 parts: good
Factory common repower engine — you entered “Yanmar 3YM30”
Current-generation Yanmar with full dealer support; raw water pump impellers are Jabsco-compatible.
Parts sources: Mack Boring & Parts (Yanmar distributor), Yanmar USA genuine parts
Common problems (3)
-
Leaking heat exchangers and overheating cooling
Owners report heat exchangers leaking (pressed-in tube joint) and overheating; trapped air in the freshwater circuit and failed impellers are other common causes.forums.ybw.com · forums.sailboatowners.com
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Seawater pump leaks cooling
The Johnson seawater pump is a frequent leak source, and leaks near the elbow hose can corrode the starter and heat exchanger studs.forums.ybw.com
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Restrictive cast iron elbow exhaust
The cast iron exhaust riser/elbow clogs with soot, raising back pressure.forums.ybw.com
Maker’s service schedule (18)
| Engine oil & filter change | 150 hrs or 1 yr | “4.3.4 Inspection Every 150 Hrs (or one year). (1) Replace the Engine Oil” — manufacturer, j30.us |
| Replace engine oil filter | 250 hrs or 1 yr | “4.3.5 Inspection Every 250 Hrs (or one year).” — manufacturer, j30.us |
| Transmission fluid change KM marine gear (shaft drive) | 150 hrs or 1 yr | “4.3.4 Inspection Every 150 Hrs (or one year). ... (2) Replace the Marine Gear oil” — manufacturer, j30.us |
| Transmission fluid change SD sail-drive installations | 100 hrs or 6 mo | “4.3.3 Inspection Every 100 Hrs (or six months). (1) Replace the Sail Drive Oil” — manufacturer, j30.us |
| Fuel filters & water separator | 250 hrs or 1 yr | “4.3.5 Inspection Every 250 Hrs (or one year). (1) Replace the Fuel Tank Refer to 4.3.1(4). (2) Replace the Fuel Filter” — manufacturer, j30.us |
| Drain fuel/water separator | 50 hrs or 1 mo | “4.3.2 Inspection Every 50 Hrs. (or Monthly) (1) Drain the fuel/water separator.” — manufacturer, j30.us |
| Drain fuel tank (water/sediment) | 250 hrs or 1 yr | “4.3.5 Inspection Every 250 Hrs (or one year). (1) Replace the Fuel Tank Refer to 4.3.1(4).” — manufacturer, j30.us |
| Raw-water pump impeller | 1,000 hrs or 4 yrs | “The impeller must be replaced with new one periodically (every 1000 hrs or 4 years whichever comes first).” — manufacturer, j30.us |
| Coolant replacement & freeze-point test | 1 yr | “Replace the fresh water coolant Every year When long life coolant is used of a specified type (see page 24), a replaceme” — manufacturer, j30.us |
| Air filter / intake silencer | 250 hrs or 1 yr | “4.3.5 Inspection Every 250 Hrs (or one year).” — manufacturer, j30.us |
| Exhaust mixing elbow inspection | 250 hrs or 1 yr | “4.3.5 Inspection Every 250 Hrs (or one year).” — manufacturer, j30.us |
| Drive belts inspect / replace | 250 hrs or 1 yr | “Replace the alternator driving belt with new one every 1000 hours or four years, whichever comes first, even if there is” — manufacturer, j30.us |
| Valve clearance check / adjust | 1,000 hrs or 4 yrs | “4.3.6 Inspection Every 1000 Hrs (or 4 years). (1) Inspection and Adjustment of Intake/ Exhaust Valve Clearance.” — manufacturer, j30.us |
| Injector test / service | 1,000 hrs or 4 yrs | “4.3.6 Inspection Every 1000 Hrs (or 4 years). ... (2) Inspect and Adjust the Fuel Injection Spray Condition.” — manufacturer, j30.us |
| Inspect/adjust fuel injection timing (dealer) | 1,000 hrs or 4 yrs | “4.3.6 Inspection Every 1000 Hrs (or 4 years). ... (4) Inspect and Adjust the Fuel Injection Timing” — manufacturer, j30.us |
| Replace flexible engine mounts | 1,000 hrs or 4 yrs | “Be sure to replace the Yanmar flexible engine mounts every 1000 hours or 4 years, whichever comes first.” — manufacturer, j30.us |
| Breather diaphragm assembly inspection (dealer) | 1,000 hrs or 4 yrs | “4.3.6 Inspection Every 1000 Hrs (or 4 years). ... (5) Diaphragm assembly inspection” — manufacturer, j30.us |
| Check wiring connectors | 250 hrs or 1 yr | “4.3.5 Inspection Every 250 Hrs (or one year).” — manufacturer, j30.us |
Service part numbers (9)
| Oil filter | Yanmar 119305-35170 Replaces 119305-35151, 119660-35150 |
“3YM30 Basic Service Kit up to serial #E01732 ... 119305-35170 FILTER ASSY, D68XL65 (Oil)” — dealer, oldportmarine.com · “It fits Yanmar 1GM10, 2GM20F, 2YM15, 3GM, 3GM30F, 3JH2E, 3YM30, 4JH3E engines. Cross Reference: 119305-35151 119660-3515” — dealer, deltadieselparts.com |
| Fuel filter | Yanmar 104500-55710 | “Fuel Filter Element 1 104500-55710 / Fuel Filter O-Ring 1 24341-000440” — dealer, ellebogen.com · “3YM30 Basic Service Kit up to serial #E01732 ... 104500-55710 ELEMENT, FUEL FILTER” — dealer, oldportmarine.com |
| Raw-water impeller | Yanmar 128990-42570 Replaces 128990-42200 |
“3YM30 Basic Service Kit up to serial #E01732 ... 128990-42570 IMPELLER KIT” — dealer, oldportmarine.com · “(Supersedes part number: 128990-42200) ... 2YM15 3YM20 3YM27A, 3YM30R 3YM30” — dealer, palmerpower.com |
| Drive belt early 3YM30 / 3YM20, below the serial break |
Yanmar 128990-77350 | “128990-77350 3YM30 up to serial #E01732 Belt” — dealer, oldportmarine.com · “S/W Pump Belt 1 128990-77350 < E00304” — dealer, ellebogen.com |
| Drive belt later 3YM30 / 3YM20, from the serial break |
Yanmar 104511-78780 | “104511-78780 3YM30 starting serial #E01733 Belt” — dealer, oldportmarine.com · “S/W Pump Belt 1 104511-78780 E00305 >” — dealer, ellebogen.com |
| Drive belt June 2004 up to serial E20847 |
Yanmar 129612-42290 | “Alternator V-Belt 1 129612-42290 June 2004 > / < E20847” — dealer, ellebogen.com · “3YM30 Basic Service Kit up to serial #E01732 ... 129612-42290 V-BELT, A37.5 (Alternator)” — dealer, oldportmarine.com |
| Drive belt from serial E20848 (120 A alternator) |
Yanmar 128990-77580 | “Alternator Flat Belt 1 128990-77580 E20848 >” — dealer, ellebogen.com · “3YM30 Basic Service Kit starting serial #E20848 ... Serpentine belt 128990-77580” — dealer, oldportmarine.com |
| Air filter | Yanmar 128270-12540 | “Air Filter Element 1 128270-12540” — dealer, ellebogen.com · “128270-12540 Air Element” — dealer, oldportmarine.com |
| Thermostat | Yanmar 128990-49800 | “Thermostat 1 128990-49800 / Thermostat Gasket N/A Not Fitted” — dealer, ellebogen.com · “128990-49800 Thermostat” — dealer, oldportmarine.com |
From the engine maker’s parts lists, or two independent parts dealers. Numbers change with serial number and get superseded — check yours before ordering.
Model sources (8)
sailboatdata.com · practical-sailor.com · rubiconyachts.com · boattrader.com · easternyachtsales.com · listingsport.com · ecys.com · mason-sailboats.org
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Researched from public sources. Spotted an error? The sources are listed above — tell us what they got wrong.