|
| Author |
Message |
    
narrabay2
Senior Member
Username: narrabay2
Post Number: 208
Registered: 10-2019
| | Posted on Thursday, October 07, 2021 - 12:52 am: | 
|
I and the gentleman who helped develop the tachometer took the Fantail out today. 75 degrees (24C) sunny, extremely light breeze from the East, water calm.
Idles at about 220rpm, putt putt RPM is 300, it likes 400RPM to 500RPM (we ran 400 most of the time). After 500 the engine shakes much more, and at full power the cylinder head started smoking off the oil residue (very warm!). Not sure if it gets so warm due to lack of enough coolant flow, or if the heat exchanger is not adequate. I could figure that out by touching the coolant line from the heat exchanger next time. Didnt think of it this time.
As to speeds, I put a GPS knots app on my phone, it was about 4+ knots at 400 RPM. At 500 it showed 4.75 knots. At full "Captain she canna take much more of this" power it peaked at 5.88 knots GPS indicated, shaking and smoking like in a movie. So, comfortably, it seems (if the knots are accurate) to be about a 4.5 knot boat.
Here's some video, I blurred my friend because I havent had the chance to ask him but when I do I will repost without the blur.
https://youtu.be/IEs1OBZ_-Ys |
chris_spring
Senior Member
Username: chris_spring
Post Number: 152
Registered: 02-2019
| | Posted on Thursday, October 07, 2021 - 08:21 am: |
|
Bravo!
Cheers! |
miro
Senior Member
Username: miro
Post Number: 1159
Registered: 11-2001
| | Posted on Tuesday, October 12, 2021 - 06:39 pm: |
|
Looks and sounds really ice.
I run my twin at about 500 PRM more than that it just uses more fuel with no change in speed.
Boat speed is about 5-6 mph .
When coming into dock I slow down to about 300 rpm
At usual speed I make a nice wake.
Not many days left to go for a cruise now . . .miro |
narrabay2
Senior Member
Username: narrabay2
Post Number: 212
Registered: 10-2019
| | Posted on Wednesday, October 13, 2021 - 07:25 pm: |
|
Hi Miro, cool to know. question - how do you know the rpm?
Also, here is this afternoon's ride. The weather is warmer than normal and just dry and calm and beautiful, so the fantail went out again. My poor tbird, but it's all I have...
EDIT - of forgot to add that I shut her down maybe 500 ft away from the dock to see how she rows. (Moves good on the oars). But the coaming was far too weak for me to have attached the oar locks to them, and one cracked. So, that's another fix. Glue the crack and attach a different way to something else!
Also, the prop was cavitating on the closeup at the dock. When that clears up, is when I am pushing the stern down with my left hand while holding the smart phone in my right... well, at least the phone was smart...
https://youtu.be/OMfLeeU3J4Q |
chris_spring
Senior Member
Username: chris_spring
Post Number: 161
Registered: 02-2019
| | Posted on Wednesday, October 13, 2021 - 09:44 pm: |
|
WRT cavitation, the Gidley does that too. However, once I'm aboard and under way it no longer cavitates. Yours will most likely be the same.
Love the sound.
Cheers! |
narrabay2
Senior Member
Username: narrabay2
Post Number: 213
Registered: 10-2019
| | Posted on Wednesday, October 13, 2021 - 10:53 pm: |
|
hi chris yup, I should have made it clear that it cavitates when no one on board (tied to the dock) because the prop breaks the surface. getting in puts it under by enough (due to my *cough cough* 200lb weight). when underway, the fantail stern goes deeper due to the well-known fantail squat.
At Ernie's suggestion, the YT was installed way forward of the 3HP Gray location, and a big battery in the nose. still squats just as much, several inches I would say, oh well at least it doesnt cavitate! I did consider putting adjustable "planes" on the rear keel just to see if that would level out the boat when under way... maybe someday try that...
there is 6ft between the rear coaming and the YT and I thought of adding removeable seat extension so there's 6ft of flat surface for sleeping, and having a canvas-maker create a "cabin" that could be snapped on all the way around the coaming (like the old Fantails with the roof, only add screened sides)...
most of the harbors around our bay have guest moorings you can use for a night or two, not to mention anchorages. thought it might be cool to spend a night on board with the ripples lapping the hull, then motor into town for breakfast... good cheap honest fun |
|
|
|
|
