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2004 Mainship 400 Trawler

Bradenton, Florida


This Ever Popular Mainship 400 is the Ultimate in a Fast Trawler. Economical at trawler speeds 8-9 kts and a fast cruise planning up to 18 kts. Loaded with many features and safety with large walk around decks and railings. She has been well cared for and Has A Great Options Package.  Her 2 Stateroom Layout Makes This A Perfect Choice For The Great Loop Or ICW Cruiser. Twin Yanmar 240hp, Bow Thruster,  2005  AB model 10VS Inflatable Dinghy Included.   Enclosed Bridge deck with new canvas in 2021 for when the kids sleep over, rain protection and open-air enjoyment dockside or cruising. Bridge complete with Jenn-air grill, bar sink and combo. One of the largest bridge decks on any 40-footer.  Cockpit area and walkways all have overhead rain protection.  Large swim platform, Outboard bracket, transom door and boarding ladder. Complete dual upper and lower station controls with Raymarine Chartplotters, Depth sounder, 48 mile digital radar, dual VHF radio, Raymarine Autopilot with a wireless remote.  Dual VHF antennas.  Both stations have full engine, bow thruster, trim tab, and remote windlass controls. Remote searchlight control, dual trumpet horn.  Full engine instrumentation. Bridge stereo system with remote control.   Set up for vacationing or long-distance cruising, self-contained capability in a trustworthy hull. Easy to manuver when docking - this vessel is perfect for the cruising couple or single handing. 

Recent Upgrades include:

New Bimini in 2021

Both Air Conditioners Replaced in 2022

New Bottom Paint  September 2022

New Vacu Flush in 2022

New Batteries 2022

Engines Serviced to include coolers and heat exchangers 2022\7 4555555+

Basic Boat Info

Boat Name: Seventh Sun III
Make: Mainship
Model: 400 Trawler
Year: 2004
Condition: Used
Category: Power
Construction: Fiberglass
Boat Hull ID: MPTND170D404
Has Hull ID: Yes


Length: 40 ft
Length Overall: 41'4 ft
Waterline Length: 38'4 ft
Beam: 14'2 ft
Max Draft: 3'8 ft
Bridge Clearance: 19'2 ft
Cabin Headroom: 6'6 ft
Dry Weight: 24,000 lb
Electrical Circuit: 12 V
Single Berths: 6
Cabins Count: 2

Engines / Speed

Engines: 2
Engine #1 Specs:
  • Make: Yanmar
  • Model: 4LHA STP
  • Drive Type: Direct
  • Fuel: Diesel
  • Engine Power: 240hp
  • Type: Inboard
  • Propeller Type: 4 Blade, Bronze
  • Year: 2004
  • Engine Hours: 1780
  • Engine Location: Port
Engine #2 Specs:
  • Make: Yanmar
  • Model: 4LHA STP
  • Drive Type: Direct
  • Fuel: Diesel
  • Engine Power: 240hp
  • Type: Inboard
  • Propeller Type: 4 Blade, Bronze
  • Year: 2004
  • Engine Hours: 1790
  • Engine Location: Starboard
Total Engine Power: 480hp
Cruising Speed: 13.9 kn
Propeller RPM: 2800
Maximum Speed: 17.38 kn


Fuel Tanks: 2
Fuel Tank Capacity: 150 gal
Fuel Tank Material: Aluminum
Water Tanks: 2
Water Tank Capacity: 65 gal
Water Tank Material: Plastic
Holding Tank Count: 1
Holding Tank Capacity: 47 gal


Heads Count: 1
Drive Type: Direct
Trim Tabs: Yes
Windlass Type: Electric
Boat Class: Trawlers, Motor Yachts


Dale Rudischhauser
Grand Slam Yacht Sales Inc


Grand Slam Yacht Sales Inc.
Main Office 16991 State Road 31
Fort Myers, Florida, US, 33905
The Company offers the details of this vessel in good faith but cannot guarantee or warrant the accuracy of this information nor warrant the condition of the vessel. A buyer should instruct his agents, or his surveyors, to investigate such details as the buyer desires validated. This vessel is offered subject to prior sale, price change, or withdrawal without notice.


Pricess 3 burner stove




Raymarine Smart Controller Romote Autopilot



Manufacturer Provided Description


There is plenty of room for seating and relaxing on the bridge. There is even a Summer Kitchen option providing a grill, sink and icemaker aft of the centerline helm. Wide molded steps offer safe and secure footing to the covered aft deck. Going forward, there are wide, lighted and recessed walkways with overhead protection leading to the foredeck. A stainless steel Sampson post and dual roller pulpit is perfect for setting the anchor and the optional windlass makes retrieval a snap. All rails, hatches and portlights are now fashioned from 316L stainless steel for easy maintenance and great looks. For 2003, all Mainships, including the new 400, are featuring beautiful cherry wood interiors. All cabinets, drawers and tables are solid cherry and the optional cherry and holly sole is very traditional as well as serviceable. The extended salon includes an Ultra leather( sofa, entertainment center with Bose( audio system, and Luce( flat screen TV. A starboard side galley offers a full size, dual voltage refrigerator and freezer, microwave, 3-burner range and oven, and even a coffee maker. Special attention has been given to general and dishware storage and the location for an under counter trash receptacle. To port of the lower station is a full dinette that seats four with a comfortable bench and two chairs. Forward, is a master stateroom with a centerline inner spring queen berth and plenty of hanging, drawer and locker storage. A second stateroom offers two single berths and an optional innovative desk arrangement, and the head, with a separate stall shower is accessible from the master stateroom or the companionway.
Mainship 400 Overview

Seventh Sun III is a 2004 Mainship 400 Flybridge Sedan Fast Trawler in nice condition. For Propulsion She offers the Economical and Desirable Twin Yanmar 240hp engine package, Kohler 8 kW generator 3 cylinder Diesel , bow thruster, oil change system, molded-in steps to the fully enclosed flybridge, AB Tender with Honda 15 HP 4Stroke, davit system on the swim platform. She is a Great Loop veteran, turn key and ready to cruise immediately. 


Recent upgrades and maintenance includes:

  • New bottom paint September (2022)
  • Batteries in port bank (2022)
  • New Refrigerator (2023)
  • Ice maker on flybridge (2023)
Vessel Walk Through

From the fiberglass swim platform, you walk through a starboard side transom door into the covered cockpit, where you can step up molded steps to the flybridge and aft upper deck or step out onto either side deck or enter the salon via the aluminum and glass french doors. Once inside the salon, you will find the apartment size refrigerator and freezer to starboard, galley further forward to starboard and the lower helm and side deck access door starboard forward. On the port side is the sleeper sofa and  dining table adjacent to the lower helm to starboard. Walk forward and step down to find the head with enclosed shower to starboard, guest stateroom to port and master stateroom forward. Engine room access is via salon sole hatches. On the flybridge is L-shaped seating to port, a bench seat to starboard, a centered captains chair with port and starboard molded seating and a fold up table for dining or entertaining. On the aft deck is the summer kitchen with Jennaire electric cooktop and sink.

Main Cabin


The salon offers a storage sofa with built in wine rack to port. Further forward is a 4 person Dining Table.  The entertainment center components including Bose cabin speakers and an apartment size refrigerator with separate freezer are to starboard. Forward to starboard is the full, L-shaped galley and lower helm forward to starboard with side deck access door. The sole is beautiful new carpet.  Opening side windows with screens, and blinds, aluminum and glass french doors with retractable screen door aft and an opening center windshield forward.



The galley is located along the starboard bulkhead in the main cabin and features a:

  • 120 vac apartment size refrigerator with seperate freezer
  • Turntable microwave oven
  • Princess 3-burner electric cooktop with oven
  • Large double basin stainless steel sink
  • Storage cabinets and drawers


Lower Helm

The lower helm is starboard forward in the salon with side deck access door and under-sole storage and features:

  • Raymarine Handheld Autopilot Controller
  • Uniden VHF Marine IC-M502 VHF Radio with DSC
  •  Bow thruster control
  • Trim tab and windlass controls
  • Handheld Search light
  • Seafire engine shutdown override system
  • Danforth compass
  • Throttle and transmission controls
  • Full set of engine gauges



Dining space is available at the 3 person corner dinette port forward in the main cabin and at the flybridge fold-up table.

Master Stateroom

The master stateroom is located forward and offers an island queen size berth, reading lights, overhead hatch with screen and sunshade, 2 portlights, storage drawers and lighted cabinets, hanging lockers, flat screen TV, carpeted sole and direct access to the head with enclosed shower.

Guest Room

The guest stateroom is located to port and offers side by side single berths, hanging locker, shelf, storage under the berths, hanging bar, port light, carpeted sole and overhead hatch. The head is to starboard with an enclosed shower.



  • Vacuflush Toilet
  • Stainless Steel Sink and Corian Countertop
  • Separate Shower\tub Stall with bi-fold Glass Doors
  • Opening Overhead Hatch
  • Portlight with Screen
  • Mirror and Teak Trim
  • Light with wall switch

The flybridge offers a full enclosure, helm centered forward with captains chair and two molded seats at the helm, bench seat with storage on each side, fold-up centerline table and non-skid deck, open aft deck with a summer kitchen with Jennaire electric cooktop, sink, and ice maker, small table, and hinged mast and features:

  • New Canvas 2021
  • Raymarine Radar
  • Raymarine Autopilot
  • VHF Marine IC-M506 VHF Radio with DSC
  • Bow thruster control
  • Trim tab and windlass controls
  • Seafire engine shutdown override system
  • Danforth compass
  • Throttle and transmission controls
  • Full set of engine gauges
  • Stereo with speakers

The cockpit offers a hardtop, non-skid deck, transom gate to the fiberglass swim platform and tender, molded steps to the flybridge, side deck access, lazarette, water maker and generator access, transom storage compartments and a fresh water shower.

Audio Video Equipment

This yacht features the following audio/Video equipment:

  • 24" flat screen TV in the master stateroom
  • 32" flat screen TV in the main cabin
  • Bose surround sound system with speakers
  • Dual MXD340SXM Stereo with speakers on the flybridge
Additional Information


Overall length 41’4”

Beam 14’2”

Draft   3’-8”

Headroom 6’6”

Sleeping Capacity 6+ enclosed bridge lounges

Displacement 24,000 lbs dry

Fuel capacity 300 gal twin alum’ baffled tanks

Water 130 gal in 2 tanks

Holding tank 47 gal


Power & Systems

Twin Yanmar 240 hp Turbo Diesels

Engine 1 -   hrs

Engine 2 -  hrs

Shafts 2” stainless with 4 blade bronze props

Dripless shaft logs

Hydraulic trim tabs

Muskrat Guards in exhausts & Sea Strainers

Engine oil change system for all 3 diesels

Freshwater cooling

Engine alarm system

Seacocks on all thru hulls easily accessible

Bronze struts and Rudders

Upper & lower Rudder indicators

Hull bottom Sealed with anti-fouling and has bottom paint maintained



Kohler 8-kw (Yanmar 3cyl diesel) in sound shield  hrs

Xantrex Freedom Inverter 3000w


Batteries & Charger

4 - Group31  batteries 

1 Group 24 deep cycle Generator 

xantrex TrueCharge

Anchoring, deck, hardware

Delta 35 lb plow with 200’ galvanized chain  

Chain/rope windlass w triple controls deck, upper, lower helm

Large stainless Sampson post

Bow locker has Sea Water Washdown

Stainless cleats bow, stern, spring, & aft folding for fenders

10 Newer Fenders

Bow lockers (2)

Stern lockers (2) for Accys and Docklines

Cockpit Fresh Water washdown

Cockpit hot and cold shower

Multiple dock lines and lengths

Folding radar mast also with digital TV antenna

Bridge deck has protected interior folding table

Blue Awlcraft Urethane painted hull (Factory)


Interior Features

Double freedom doors to Salon & cockpit

Full sliding pocket screen door

Sleep Sofa converts to Double bed with storage under

Cherry interior

Dinette with storage under bench, cherry table, & 2 stools

Central Vacuum w attachments

Window Binds on Salon windows

Main salon Heat and A/C

Sliding windows and screens

Lower station full forward windows -w- Washers and Wipers

Custom ships wheel lower station & full instrumentation

Sliding door lower station to deck

Bose 321 stereo system with CD/DVD player

Flat panel TV wired for dockside cable and digital air TV

Lower helm center window opens

Interior lighting overhead and safety lighting

Carpeted staircase to lower-level cabins

Combination Washer & Dryer berth area


Master State Room

   Queen island bed, storage under

   Inner spring mattress, custom sheets & bedspread

   Cedar lined closets

   Overhead and reading lights

   Automatic closet lights

   Storage drawers

   Flat panel TV

   Access to bath

   Opening hatch with sliding screen & shade

   2 screened opening portlights

   Second A/C for berth areas


Guest Stateroom

   Hanging locker, Auto lighting, and shelves

   Two single berths with high density foam mattresses

   Opening hatch with screen

   Open portlight with screen

   Cherry storage cabinets & Reading lamps



All molded fiberglass

Separate tub/shower with seat & shower door

Built in vanity and two storage bins

Electric toilet w/Holding tank

Macerator pump

Mirror and towel holders

Opening hatch with screen/sunshade

Opening screened portlight frosted

Panned floor with drain

Dual entry access from master stateroom and hall



Corian counters with Corian edge protection

Dual Stainless sinks

Dish & Cup locker with glass display front

Refrigerator / freezer 120/12 volt

Electric three burner range/oven with cutting board top


Over/under counter storage & drawers

Trash bin drop, within counter



50 Amp 50 foot Shore Power cord w storage fwd / aft

Reverse Y capability limited marinas w (2) 50’ 30 amp cords

Forward and Aft shore power connections

Assortment of shore power adaptors 30 & 50 amp

Charles built in Isolation transformer for safety

Bonding system with anodes for fresh water

Circuit breakers AC/DC panels

4  Bilge Pumps, Fwd, Mid low, Mid high Emergency 4K, Cockpit Bilge

GFCI protection throughout

Water heater

Tank Tender monitors

Cable TV / Phone dockside connections w cables



A bin of spare filters, belts, impellors, parts, pump

Variety of life jackets


Automatic fire extinguisher engine compartment

Automatic fire extinguisher generator compartment

Multiple ABC hand held fire extinguishers

All Manufacturers Manuals and notebooks

    Schematics, wiring, plumbing, etc.

This Mainship is loaded and ready to cruise or just entertain dockside as your second home!

The Company offers the details of this vessel in good faith but cannot guarantee or warrant the accuracy of this information nor warrant the condition of the vessel. A buyer should instruct his agents, or his surveyors, to investigate such details as the buyer desires validated. This vessel is offered subject to prior sale, price change, or withdrawal without notice.

Disclaimer This calculator is intended solely for general informational purposes, and to provide a rough estimate based on the information you provide. You should not base your decision on this estimate alone.