Dinghy loading/unloading and break-in runs

Got up early to prepare for some runs with out new dinghy “Coconut“.  The dinghy is a 12-foot Apex Inflatable with hard bottom with a 25 hp Yamaha outboard motor. The first project was to drill the hole to pass the fuel line into the anchor locker .  The 6 gallon gas tank fits nicely in the anchor locker with enough room left over for the anchor and rode (once I get one).

Spent a few minutes setting up to lift the dinghy back into the water (we keep her stored on the back platform of Tahina).   For lifting/lowering we have a really cool setup with a sliding derrick in the boom which has two pulleys on the end.  The 2:1 main halyard lines go from the top of the mast over the end of the derrick pulleys and then hook to the lifting harness I build last month for Coconut.  We have a rope at the other end of the boom (near the mast) which pulls out the derrick so you can get the boat over the water.  However, last month we realized the derrick is about 1 to 2 feet short of the length required to get the boat past the aft transom of the boat.

Here are some photos showing Coconut up on deck, the deck mats, and Coconut in the water:

Coconut on Deck Coconut on DeckCoconut on Deck
Once I had Coconut lifted up, and the derrick out as far as possible, I worried about how to keep it pushed out from the transom so I could lower it.  I ended up sticking the mop handle in a slot on the edge of the transom. The mop handle kept the dinghy pushed out just far enough.  I began lowering and the dinghy went down just fine.  With another person, this will be easier since they could simply push it out slightly.  But, I will most likely have many times where I’m dropping the dinghy alone.  I really want to get the derrick set up so it goes out another foot or two!

Once Coconut was in the water, I put away the derrick and halyard.  Then I got things ready for a break-in run.  I had a bit of difficulty getting it started with the rope lanyard.  But, once I squeezed the fuel bladder a few times it finally got enough fuel to start.  I let it run at idle for 10 minutes per instructions in the manual.  Then I took it for a few short runs at half-or-less throttle.  This needed to be done for 50 minutes.  The good news is that this boat planes quickly (without too much throttle needed) when only one person is on board.  And, it was plenty quick at even half throttle.

Later in the day, after it warmed up some, I took Coconut on a longer run at higher speeds (again staying within the manual recommendations).  The first 10 hours of engine use are constrained a bit.  But, I did notice this boat reaches its top speed well before full throttle with only one person on board.  I suspect the boat is going 5-10 knots faster than we did at full throttle with the 15 hp motor we had on our earlier dinghy (same model/manufacturer dinghy).

Of course, I took my handheld GPS with me while doing the trial runs. You can see the dinghy trial runs in Google Earth. I used GPSVisualizer.com to colorize the tracks according to speed (in knots). Toward the end of the trials I did I was allowed to briefly open up the throttle. It looks like Coconut tops out at a little over 25 knots with just one person on board!

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