Quicksilver 460

[Barneyt]

Hi.
Anyone out there able to help me with this? I have a Quicksilver 460 fitted with a Tohatsu 30hp outboard which has done about 30hrs. Do any of you know what sort of speed I could reasonably expect from this set up. Thanks for any help etc

 

[rafiki_]

Sorry no idea, but worth a bump up.

 

[Danfarry]

http://youtu.be/0O4mvcMi-bo

The one in the video has 50hp....

 

[Spi D]

What is your ready-to-go weight, all incl?

Boat, motor, crew, gear, fuel etc.

 

[Barneyt]

I reckon the weight is around 560kg

 

[Barneyt]

Sorry, about 650kg

 

[Spi D]

30 hp will push 650 kg of almost flat bottom hull to approx. 25 knots, given right prop allowing the engine to reach max. recommended rpm. at full throttle.

Weight is your enemy, so remove any dead weight....

 

[Barneyt]

Thanks for that. It has a planing hull. What do think then, please?

 

[Spi D]

It is planing indeed. Planing hulls commonly are deep V, modified V or almost flat (referring to dead rise angle).

Yours is almost flat.

In this pic parked next to a deep V

 

[Barneyt]

Ok, thank you very much for your input.

Take care

 

[ontheplane]

30hp for a 600kg boat isn't a lot - i'd estimate it would do 25kts, but only with a perfectly clean bottom and all else being perfect.

As above, get weight down as much as possible, and perhaps one of those hydrofoil thingies on the cavitation plate.

 

[Spi D]

Since only 30 hrs I presume the engine is new(ish), hence 4-stroke.

That engine has max. rpm 6250 at wot and a gear ratio of 2.17.

30 hp pushing 650 kg equals 23 knots if deep V, 25 knots if modified, 28 if flat bottom hull.

For an engine spinning 6250 rpm, reduced 2.17:1, to hit these speeds the prop pitch needs to be 10", 11" or 12" respectively. Taking prop slip into consideration I'd suggest to test 13" on the boat in question with an option to go lower.

 

[Davy_S]

I do not think that you will get 25 knots with a 30hp, more like 18 knots if you keep it balanced and light. a hydrofoil will not help at top end, but will certainly help in getting up on the plane.

 

[Spi D]

I do not think that you will get 25 knots with a 30hp, more like 18 knots if you keep it balanced and light. a hydrofoil will not help at top end, but will certainly help in getting up on the plane.

Agreed about the hydrofoil. This hull, wide and a bit butt-nosed, most likely have no issues getting on plane and stayning there also at lower speeds, still provided load and distribution is kept optimal.

The max rated hp is 60 (at least for the current 455), so 30 is far from allowing it to perform as optimally designed to.