Elton, Norrie bought a boat!!!!!!!

[Guest NickInTheNorth]

John, just give me a few days notice and the bread will be there

[Sharkbyte]

Hi Norrie,

 

49 Knots and 50hp, there is definitely something going wrong with the GPS readings.

 

Doing a simple calculation from a fully loaded up weight of 1000lbs and a 50 hp engine putting out around 47hp accounting for transmission losses, top whack should be no more than about 38mph a very respectable speed indeed.

 

To give you 55mph at 1000lbs you would need around 110hp and thats 1000lbs including the weight of that 110hp engine!

 

I ran our boats stats through the calculation and it came out at 32 mph. On Friday on a mirror like sea we topped out at 31mph so it is pretty accurate.

 

The calculation is based on the 'average planing hull' so a little variation is to be expected but unless your running with nearly a 20 knot tide the maths dont work I'm afraid.

[spasor]

Nick.

Myself and jabee believe you and Norrie. `Cos we`ve seen the way he drives!

I have personaly reached speeds in excess of 90mph on the road to Lochaline in a vain attempt to catch up with the sod!!

Paul.

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Does that guarantee our bread?

[Guest NickInTheNorth]

Hi Sharkbyte

 

just to show that calculations can prove anything take a look here

 

using the figures you have used (1000 lbs 47hp, but based on catermaran hull form - which is closest to a cathedral hull) this calculator gives a speed of 60 (I am assuming mph rather than knots per hour).

 

If we take your 110hp, and increase the weight to 1500 then we get a speed of 74!!

 

Would be very interested to see what sort of speed this calculator gives for your boat, can you give us the weight, hp and hull form for comparison.

 

[ 15. June 2005, 09:38 AM: Message edited by: NickInTheNorth ]

[jabee]

spasor:

I have personaly reached speeds in excess of 90mph on the road to Lochaline in a vain attempt to catch up with the sod!!

Taking it easy was he?

[Guest NickInTheNorth]

he was trying to get to jeans snack shack before closing time

[thurso angler]

Why is everyone so bothered what speed norries boat goes its obviously fast and hes obviously very happy with it so why all the time spent trying to disproove this??

[Guest stevie cop]

Sharkbytes boat is a 17ft Wilson Flyer. They have a cathederal hull. I believe that he has a 70 hp Yamaha on the back of his.

 

I also have a 17ft Wilson Flyer, but mines only got a 55 hp on the back. My boat does about 23 knots flat out with 2 or 3 adults on board and all the usual gear. What's 23 knots in mph?

 

I reckon that Norrie's shorty is a bit lighter than the Wilson's, so with a 70 hp on the back I'd say it goes a bit quicker than Sharkbyte's Wilson, which does 31 MPH flat out. If I was asked to give an educated guess, (which I haven't been! ;o), I'd say that Norries boat would probably do around 35-36 MPH. That's MPH, not knots.

 

47 knots, or 50+ mph with a 70hp outboard just doesn't sound right. I know it's not important how fast your boat can go, but it is important to know how fast it goes. If the GPS is not working properly, you need to know. Also, if the GPS packed up while you were out, you'd need a rough idea of your speed to navigate your way back in.

[Guest stevie cop]

Oops! I just re-read your original post about the speed and I see that you've only got a 50 hp outboard! Sorry to have to inform you Norrie, but something is wrong with your GPS. There is no way on Gods earth that your boat would do anything like 47 knots with a 50 on it, and yet you say that there was still plenty left on the throttle at that speed! If I were you, I'd get the GPS checked out mate.

 

Are you sure you aren't reading the rev counter thinking it's a speedo? You wouldn't be the first, or the last!

 

If that boat is rated for up 70 hp, and it does 47 knots with 50 hp, how fast would it go with 70 hp? My guess is that the boat wouldn't be safe at 47 knots, so it would be downright dangerous with a 70 on it.

 

[ 15. June 2005, 10:33 AM: Message edited by: Steve Coppolo ]

[Guest NickInTheNorth]

I don't understand the need to disprove the speed. Norrie is happy with the boat, as I was, and as Alan Taylor was before me. It is a very fast boat.

 

The Wilson Flyer is a fine boat, but is a much heavier laid up boat. It is very solid and weighs much more than a seahog for the same size. (I know three people with Flyers). Your boats are longer, and I believe wider. The seahog shortie is a very light boat.

 

Did you try the calculator I posted a link to, which seems to suggest that it is possible that the facts are as stated?

 

I have timed the boat over a known distance, I know how fast it goes. Seems safe at 47 knots to me. At least I've lived to tell the tale. But I would not like to see it with much more power on the back. Having said which a larger, heavier engine would spoil the trim, increase the weight, and probably not increase the top speed by that much.