# Fishing Trawler Repower with 320 HP Marine Diesel and Reduction Gearbox

> A trawler owner needed to replace a worn, high-fuel-consumption main engine before the next fishing season.

- URL: https://www.marine-equipment-supply.com/projects/fishing-trawler-repower-sdec-d683/
- Region: Vietnam — Southeast Asia
- Sector: Commercial fishing
- Customer type: Owner-operator of a 24 m steel offshore trawler

## Overview

A trawler owner needed to replace a worn, high-fuel-consumption main engine before the next fishing season. The vessel had a conventional single-shaft layout and a fixed-pitch propeller, so the replacement package had to match the existing shaft line and engine bed with minimal structural work.

## Challenge

The old engine was out of production and spare parts were becoming difficult to source. The owner wanted a modern water-cooled engine with a heat-exchanger cooling system, a matching reduction gearbox with the correct ratio for the existing propeller, and delivery within the six-week dry-dock window.

## Solution

| Item | Model | Qty |
| --- | --- | --- |
| Marine diesel engine | SDEC D683, 320 HP @ 2200 rpm, inline 6-cylinder, heat-exchanger cooled | 1 |
| Marine reduction gearbox | Advance 135A, ratio 4:1 | 1 |
| Propulsion accessories | Flexible coupling, engine mounts, wet exhaust elbow, instrument panel, wiring harness | 1 set |
| Spare parts kit | Filters, belts, impellers, gaskets for 2,000 hours | 1 set |

The engine and gearbox were matched at our workshop for flange alignment and shaft speed, then run-tested together before packing.

## Scope of supply

Engineering selection, factory test with report and video, export wooden-box packing, FOB Shanghai, installation drawings, and remote commissioning support by video call.

## Outcome

The package was installed within the dry-dock window. The owner reported lower fuel consumption at cruising speed and a full season without unplanned stops. A second vessel in the same family fleet has since been quoted with the same package.

## Products used

- [SDEC D683 (6CTA8.3-M220) Marine Diesel Engine (250-360 HP)](https://www.marine-equipment-supply.com/products/diesel-engines/sdec-d683-6cta8-3-m220-marine-diesel-engine-250-360-hp/)
- [SDEC D683 Marine Diesel Engine (320 HP)](https://www.marine-equipment-supply.com/products/diesel-engines/sdec-d683-marine-diesel-engine-320-hp/)
- [Advance 135A Marine Reduction Gearbox — Ratio 3:1](https://www.marine-equipment-supply.com/products/marine-gearboxes/advance-135a-marine-reduction-gearbox-ratio-3-1/)
- [Advance 135A Marine Reduction Gearbox — Ratio 4:1](https://www.marine-equipment-supply.com/products/marine-gearboxes/advance-135a-marine-reduction-gearbox-ratio-4-1/)
- [Advance 135A Marine Reduction Gearbox — Ratio 5:1](https://www.marine-equipment-supply.com/products/marine-gearboxes/advance-135a-marine-reduction-gearbox-ratio-5-1/)