When I was securing the fishing gear, I saw the Whaler Drive was being washed over by waves, and I thought that was interesting, But I was not alarmed--yet. With me and one crew in the helm seats, I advanced the engine throttles the usual amount--maybe half way or so--to get the boat speed to increase to plane. I noticed right away the 23 WALKAROUND Whaler Drive boat was hesitating, was bogged down, and was not reaching planing speed; the bow stayed high.
Looking aft at the outboard engine cowlings, they looked to be lower in the water than normal, and perhaps so low to the waterline that the engine cowling seal line was below water. I was now alarmed. I felt like the boat had taken on water for some unknown reason; I reduced the engine throttle in order to make an assessment.
The engines were at mid-trim and the trim tabs were all way up. At this time my friend noted water in the forward cabin that was three or four inches deep. I was now alarmed (but did not show that to my crew).
The presence of water in the cabin confirmed the boat had taken on water. Without further hesitation I trimmed the engines to all the way down, set the trim tabs to all the way down, and I turned on the three sump pumps on the boat. These pumps had not been automatically started. I slammed the throttles to full power, and then watched the engine cowlings. The engine cowlings were still too low and the boat was still bogged down, but slowly the boat accelerated and reached plane. My friend was smiling and unconcerned and somewhat oblivious to my internal panic and they were still otherwise enjoying the trip.
Once on plane I set course for Sandsprit Park where I planned to go into shallow water at the dock in case I needed to haul out the boat and assess the source of the swamping. Upon arriving I was quickly able to determine the bilge pumps had removed all of the water and that we were taking on no more water. From there we continued back to my home boat lift.
The post-mortem produced an initial theory that the live well was the source of the water ingress. The live well pump provides water into the live well, which flows out of a vertical tube top that was level almost to the top of the live well. During our trip out with the bow trimmed up the live well was thus spilling water down into the bilge unnoticed. Note the Rohlfing's had never operated the boat with the live well functional.
The swamping occurred due to the number one aft bilge pump float not operating by its float switch. Normally the float would have (and previously had) turned on the number one bilge pump, and a lamp on the helm console would alert me that the pump was running. (The pump running due to the float switch would have meant that the amount of water in the bilge was greater than a few gallons.)
The boat had been in a boat yard to get the new engines (and a new fuel tank) installed. Apparently, when I cleaned the bilge afterward, I neglected to remove the float switch cover and remove any silt in that area; that may have hampered operation of the float. Or, the float switch just decided to fail. I could not get the float switch to work again after cleaning out the silt.
To make matters worse the other two bilge pumps had defects. The second aft bilge pump had stopped working. This was even though the panel switch light came on to show it had power, and I had heard it and the other two bilge pump motors hum during a pre-flight bilge pump check before leaving the lift. Also, the forward bilge pump, although set for operation via its float switch, would not come on; thus there was also no indication that there was water in the cabin. In total, the bilge pumps were a comedy of errors. Also, I think we would have experienced bigger problem without the 200-lbs of ballast in the bow area, or if we had more than crew aboard. Murphy never sleeps.
For corrective action I have:
- reduced the height of the live well drain tube such that it does not overflow water to the bilge, and
- replaced all three bilge pumps and their float switches.
BACKSTORY
For two years now I have had a 1993 23 Walkaround Whaler Drive boat that now has twin 2020 Yamaha 200-HP four-stroke-power-cycle engines with 25-inch shaft length. The engine mounting height [here the description was ambiguous--please only describe engine mounting height by stating the number of units of 0.75-inch or "holes" the engine has been raised from the lowest possible mounting position].
This boat was previously named KATCHMANDU and had twin Yamaha 150-HP two-stroke power-cycle engines; the former owners were Jeff Rohlfing and his father. Jeff had documented many of its characteristics in the continuousWave forum and on his facebook site.
The c.1993 23 WALKAROUND Whaler Drive boat [with twin engines] is generally considered to be stern heavy. That would be hard to argue against. On my particular boat there are
- a 150-gallon fuel tank under the cockpit deck in the [stern] half of the boat;
- twin 200-HP fourstronke engines on a Whaler Drive
- a few people in the cockpit
The twin Yamaha F200 engines have a dry total weight of about 1,000-lbs. Previously the twin Yamaha 150 engines weighed about 788-lbs. Two large engine batteries and a 10 to 15-gallon live well are in the transom area. Because of the added engine weight aft, I have put 200-lbs of ballast into the cabin forward storage compartment to level out the trim.
In this configuration a 23 WALKAROUND Whaler Drive boat comes off plane with the engines at mid-trim and trim tabs up, and comes off plane faster quicker with the engines trimmed fully down, and fastest off plan if the trim tabs are trimmed all way down. When coming off plane the backwash is about even with the engine cowling seal line. This is acceptable to me, but I would like to improve on that, [that is, to keep the engine cowlings at a higher position relative to the following sea that results when coming off plane]. Water is not entering the cockpit through the scuppers or through the transom door or washing over the top of the Whaler Drive.
The engine speed [at an unidentified boat speed called "cruising speed] is in the range of 3,300 to 5,000-RPM. Best fuel economy [occurs at an unidentified engine speed and unidentified boat speed and is] 3.0-MPG measured by a Yamaha gauge.
Varying with sea state, the typical cruising speeds are from 20 to 40-MPH. The full-throttle engine speed is 6,000-RPM which produces a boat speed of 50-MPH. [The propellers are identified only as] Yamaha propellers. I am happy with the performance.
I believe the 23 WALKAROUND Whaler Drive boat has a design flaw. There is a possibility for the boat to swamp--which I nearly experienced and described above.