You may be scratching your heads here wondering if the title is a ploy to just get your attention or if this is actually true! Well believe it, it is! Last year this project was proposed to us, and when asked if we could put a hot tub in the boat we said “sure thing” and then with the opportunity to add the new diesel outboards on the transom we jumped with excitement. You don’t get many of opportunities like this!
What did we think about the new OXE diesel outboards! In a nutshell we were impressed. They alter the expectation of what a diesel should look, sound, and perform like. If the cowling didn’t have the word diesel on the side, a novice boat owner might not even think to question what type of fuel to put in the tank.
Our 31’ GT Coupe would of paired better with the larger 300HP Diesel Outboards coming to market over the next year but due to the timeliness of the project the 200’s were the biggest we had to work with. The overall weight of the boat came to 10,200 lbs which is normal for our other GT Coupe builds, but those vessels normally also have a pair of 300HP Outboards at a minimum. The top end speed definitely suffered from the 200HP delta on this hull. We topped the boat out around 36 mph, which still allowed for a comfortable 28mph cruise speed. That cruise speed is comparable to other vessels we build in this category.
The vibration of the 4 cylinder diesel block is noticeable. To most at idle it will be apparent this is not a normal 4 cycle gas engine. Almost similar to that of the older two-stroke engines. But it quickly goes away with a little throttle. Once you reach 2,000 rpms the engine smooths out to a quiet purr. It rivals that of any other outboard on the market with little to no vibration at speed.
Throttle response was also a two sided situation. If idling and looking for a quick punch of acceleration, you find a fairly long period of throttle lag (2-3 seconds), due to the turbo spooling up. But once it get spooled up, it is on point. Throttle response goes from melancholy to exhilarating. You can really feel the punch from the turbo at speeds over 2,500 rpms. Even with a big heavy boat like ours.
The overall integration of the engine rigging was quite similar to that of other outboard brands as well. The digital throttle allowed for us to mount it on the Shockwave Seats armrest. We do this so that it moves in suspension with the main operator. The engine display is shown here in the top right of the dash. It is a nice 7” display that gives all the engine data you will need.
We found the best fuel efficiency to be around 1.7 MPG on this boat. We obviously know the engines were a little under powered on this size vessel so they were not at the most fuel efficient RPM when we did reach our 28mph cruise speed. On a smaller 8000-9000lb vessel I think we would find a real fuel savings over other traditional gas outboards. But with all that said the recorded 1.7 mpg is still on par with the larger HP gas motors.
Conclusion
These OXE diesels are right there knocking on the door of the large gas outboard market. They have proven you can take a diesel engine, and apply the technology in an outboard application with success. For a lot of users this is what they have been waiting for. It now can eliminate the necessity of having gasoline on a larger yacht or fuel depot. Hats off to OXE for showing us that a diesel can be quiet, smooth, and responsive. It will be fun to see how the shoot out continues with the larger 300HP variants coming out from both OXE and competitor COX.
NOW THE FUN PART - THE HOT TUB
With two diesel boilers circulating hot water through a heat exchanger we were able to create a replica model of your at home system. With temperature able to reach 100+ degrees you can relax all evening after a long day out on the water. And with enough space for 4 adults you can invites your friends over as well!
The primary principle of the system works due to the amount of flotation we generate with our collar systems. In fact even with the hot tub full you will see how flat and stable the boat looks in the water.
This boat really was complete and ready for any adventure. We incorporated our drop bow door, in deck fish boxes, two top of the line suspension seats, seating in the main cabin for 7, a full electric flushing head, and of course the hot tub!
We will continue to offer this option for clients on a case by case basis. Overall this option will add an additional $19,000 to the bill. But it all depends on what else is incorporated into the build and if we need to account for any other unique options.