Sea Trials Composite Catamaran Honda BF 40's

[stevemid]

You may recall that a boat identical to the one I am building was built up on Lake Maquarie and Frank the original builder sadly died of cancer. Phil, who helps me with my boat from time to time finished the boat for Frank's wife almost a year ago. Today we took it out on the Lake for it's first sea trials prior to her putting it up for sale. I was particularly interested in how the 40HP Honda motors would push the boat along as I haven't yet made a power commitment.

Getting the boat to the lake was our first challenge as none of us have a big 4WD. So we used Phil's 1986 240 diesel 2WD hilux. The little diesel took the job in stride for the journey from Swansea to the ramp at Vallentine's Bay (about 5 km.) The combined weight of the boat and trailer was probably around 1200-1300kg and the little truck had no problems with launch and recovery, not even looking like spinning a wheel. The pictures don't really show how much this looked like a flea pulling an elephant!

The sea trials went excellent with the exception that the motors seemed way low in the water and the analogue RPM guages seemed to read lower than the actual revs. After an hour of pottering around at trolling speeds, here's what we measured off the gauges and the GPS:

2 X Honda BF 40 pushing 7M composite cat
500 3.5 knots
1000 5.8
1500 9.9
2000 15.0
2500 19.5

At 2500, from the position of the controls and how they sounded, I'd say the motors were running closer to 3/4 WOT and we didn't want to rev any higher this early in the run-in period. I thought I read in another thread that there's a setting or a switch somewhere on the motor to get the correct RPM readings.
Steve
By the way we did align the motors before setting off (this is an older pic.)
Stb Side.jpgStern Canvas.jpgphoto-16.JPGCav Plate.jpg

[Schulzy]

That's pretty good speeds for 40s! it doesn't look right that big of a boat with such small motors. pitty old mate never got to go for a ride in it before he passed away

[Giffo65]

Nice looking boat, pity the builder do not get to see his dream hit the water. Do you have a thread on your build,would be very interesting read. What is the composite material ?.I was at the boat show last weekend and there was some flash new boat building materials there !

[stevemid]

That's pretty good speeds for 40s! it doesn't look right that big of a boat with such small motors. pitty old mate never got to go for a ride in it before he passed away

Yeah Shulzy it just don't seem right but because of the use of a light-weight sandwich flat panel kit the boat is much lighter than your average production cat of this style and size (full lock up enclosed cabin, queen berth.) This is not only an advantage for towing but also much less required horsepower, fuel use etc.

Steve

[stevemid]

Nice looking boat, pity the builder do not get to see his dream hit the water. Do you have a thread on your build,would be very interesting read. What is the composite material ?.I was at the boat show last weekend and there was some flash new boat building materials there !

Giffo65, It's here: http://www.ausfish.com.au/vforum/sho...-updates/page1
Steve

[thelump]

Does look like a big bit of gear for 40s. Did it make your mind up re power for yours Steve? Also why did you go to Valentine when there are 3 ramps at Swansea?

[wirlybird]

how much are they selling it for?

[stevemid]

how much are they selling it for?

She's still shopping brokers but my guess would be it will probably end up 10k either side of 100 based on what the designer told her.
Steve

[Spaniard_King]

The Tachos need to have the selector switch on the back of the Tacho set to position # 1

[stevemid]

The Tachos need to have the selector switch on the back of the Tacho set to position # 1

Thanks Garry
Steve

[stevemid]

Does look like a big bit of gear for 40s. Did it make your mind up re power for yours Steve? Also why did you go to Valentine when there are 3 ramps at Swansea?

We made the decision to go to Valentine due to potential issues with current and a sharper drop off in the channel. This was the first launch this boat off this trailer and we wanted to make it as easy as possible on ourselves.

Haven't decided yet on my power. The showing of these 40's gives a strong vote for the Honda 50; it's the same motor, comes in an extra long leg, and the extra 10 HP should give me a comfortable 20 knot cruise speed. For an extra 3 grand I can have the Suzuki 60's 29 Knots WOT and few more MPH on cruise or better fuel economy at 20 knots. Or I could have the Yamaha 70's, my first choice, originally and more of everything including $. I will know for certain once I put the money down.
Steve