I agree but the heavy Surfury blasts along as it should being an off shore racer and much faster than when powered by an Irvine 61 plus it all stays nice and cool. it will take 6 s too but there is no need. The lighter Cigarette is running a 2045 KVA with 120 A speedo both water cooled from HK, running a 45 mm prop on 4 cell again quick runs cool without hassle.
I run 5s in a Pursuit 1650 KVA with 120A hk speedo, shallow V on 3 bladed bronze prop it goes like stink but not sure motor would take 6 s, so there are lots of combinations that seem to work ok

Hi Guys
If you use the 3639-1100kv(800 Watts), you can straight change over to a 3648-1450kv(1600 Watts).

So starting with the 1100kv
3s=12,210 rpm
4S=16,280 rpm

The 1450kv
3S=16,095 rpm
4S= 21,460rpm

Only double the power and 5,000 rpm more!!!!
And the 1450kv can handle 6S, if you are brave !!!!!

Canabus

I run 1100KVA brushless from HK watercooled with 120A watercooled speedo on 4s 5200`s in my Surfury and Cigarette 36" and they belt along with 50mm 2blade Mocom props but you dont have to run it flat out.

Many thanks Canabus for your reply! /Bengtt

Hi Bengtt

For that size model I use a Hobbyking 3639-1100kv brushless motor or a D3548/4 1100kv on a 3S lipo battery(between 3700-5800mah), a 60 or 100Amp car ESC (HK-60A-SL or HK-100A), program card(HK PROG-CARD).
I have a good setup for this system, if you require.

Prop start with the one you have, but I use a 2 blade 40mm or 3 Blade 37mm (brass or CNC).

Slightly over scale speed, depending on the boat.

Canabus