Pirm Udom Sub: Sustainable Diving on Koh Chang with Modern Technology
Diving on Koh Chang is an adventure that combines nature and excitement. With the Pirm Udom Sub, our specially converted dive boat, you can explore the stunning underwater world around Koh Chang in comfort and sustainability. Originally built as a marine patrol boat, the Pirm Udom Sub has been transformed into a modern platform for our diving expeditions.
From a Wooden Boat to the Pirm Udom Sub – A Step Towards Sustainability
In 2020, we retired our large wooden boat, which accommodated up to 45 divers, to focus on a more efficient and sustainable model. We chose the Pirm Udom Sub, a marine patrol boat with a half-glider steel hull. After extensive modifications, it now meets all the requirements for safe, comfortable, and eco-friendly dive expeditions.
This change has helped us reduce our environmental impact while providing a more personalized and higher-quality diving experience for our guests.
Why the Pirm Udom Sub is Perfect for Our Diving Guests
- Space for 36 tanks, 10 divers, and 3 crew members with full equipment.
- The boat has a maximum capacity of 20 passengers + 2 crew members, but we limit occupancy to 10 divers and 3 crew for optimal comfort and safety.
- A spacious dive deck at the stern for easy water access.
- Stable and safe rides thanks to optimized weight distribution and trim.
Travel Data for Our Dive Trips:
- Cruising Speed: 14 km/h at 2000 RPM – ideal for relaxed journeys to the best dive sites.
- Fuel Consumption: Efficient 30 liters per hour.
Why We Limit Our Boat to a Maximum of 10 Divers
Although the Pirm Udom Sub is licensed to carry up to 20 passengers plus crew, we have deliberately chosen to limit our dive operations to a maximum of 10 divers and 3 crew members.
This decision is a core part of our diving philosophy and directly affects safety, comfort, dive quality, and personal attention.
Quality Over Quantity – How Our 10-Diver Concept Works
Our dive days usually include up to three dives, and the 10 available diver spots are carefully allocated depending on experience level and course requirements.
To ensure smooth operations and relaxed diving, divers are typically divided into two smaller groups:
- Group 1: Certified fun divers (maximum 5 divers)
- Group 2: Courses, try dives, refreshers, or training dives
This structure allows us to adapt every dive day individually.
Practical Examples from Daily Operations
-
5 certified fun divers +
2 Advanced Open Water courses
→ The boat is considered fully booked with 7 divers, as we operate with two instructors: one instructor leads the certified fun divers, while the second instructor conducts the Advanced Open Water training. -
10 certified fun divers
→ The boat is fully booked, and no courses are scheduled, allowing both instructors to focus on guiding certified divers in small, relaxed groups. -
5 fun divers + 2 Open Water students + 2 try divers + 1
refresher
→ 10 divers total – fully booked. One instructor leads the certified fun divers, while the second instructor conducts the 2 Open Water students, 2 try divers, and 1 refresher, as these programs share the same basic skill performance requirements (equivalent to Open Water Dive 1 and 2) and can therefore be conducted together under one instructor.
This flexible system ensures that no group is rushed, instructors can focus properly on their students, and certified divers enjoy relaxed, uncrowded dives.
What This Means for Our Guests
- More space on deck and at gear stations
- Smaller dive groups and shorter entry times
- Better supervision and higher safety margins
- A calm, personal atmosphere instead of mass tourism
By limiting our numbers, we create a diving experience that is safer, more enjoyable, and more personal – exactly what many of our returning guests appreciate most.
Innovative Antifouling System for a Cleaner Environment
Our Pirm Udom Sub is equipped with advanced HD4 and HD1 Hull Shield Ultrasonic Antifouling Systems. This technology provides continuous protection against biofouling, keeping the hull clean without using harmful chemicals.
Benefits of the Hull Shield Technology:
- Reduced Cleaning: Less effort to remove algae and marine life.
- Lower Maintenance Costs: Longer lifespan of bottom paint and reduced repair expenses.
- Effective Protection: Continuous impact on hulls, drives, rudders, and more.
- Eco-Friendly: No chemical residues in the water.
Sustainability and Modern Technology Onboard
In addition to the innovative antifouling system, the Pirm Udom Sub features an integrated solar power system that reduces energy consumption and ensures reliable electricity onboard.
Our Solar Power System:
- 1800-Watt Solar Panel System: Powers the main onboard systems.
- 45-Watt Solar Panels: Separate chargers for consumer and starter batteries.
- Inverter Charger (24V/200Ah): Enables the use of 220V power for lighting and electronic devices.
Discover the Best Dive Sites on Koh Chang
With the Pirm Udom Sub, we take our guests to the most spectacular dive sites around Koh Chang, including:
- HTMS Chang – Thailand’s largest wreck, a paradise for wreck divers.
- Hin Luk Bat – A stunning coral reef teeming with marine life.
- Secret Reef – A hidden gem with pristine underwater landscapes.
Our trips offer a perfect diving experience for both beginners and experienced divers alike. Visit our Fun Dives page for more information.
Technical Highlights of the Pirm Udom Sub
- Engine: Cummins 6BTA-M1 with 260 HP.
- Propeller: 24-inch diameter, 19-inch pitch – ideal for stability and efficiency.
- Trim System: Specially designed trim tabs ensure optimal balance.
Book Your Diving Adventure on Koh Chang!
Explore the stunning underwater world with us and the Pirm Udom Sub. Learn more about our dive trips and courses at Chang Diving Center.
We look forward to showing you the best dive sites on Koh Chang – sustainably and unforgettable!
