Prop pitch

[Fenlander]

Agree Poly... it's really just a choice of dropping 1" to a 9 or 2" to an 8. With Stig having found props at £55 in the scheme of boating no big deal even if the first attempt is the wrong one. You'd probably only drop £20 selling the once used one on Ebay and getting the right one. Sorted for £75. I paid about £100 for the alternative prop for my Suzuki 20.

Of course much depends on the actual weight of Stig and crew. The description of 2 adults, three kids and a dog could equate to anything between 32 and 55+ stones.

We have easily planed the Aerotec with 20hp/10" prop at a load of 44 stones (plus 25l fuel and kit). Also with a 15hp/9" prop and load of 38 stones (plus 25l fuel and kit).

[jeffstevens763@g]

stig,
poly agrees re pitch but consider the below from propeller EU i know they do a 4 blade prop for the honda's which might solve your problem.


Most propellers have 3 blades. For speed this is the most efficient design. For extra thrust at low speeds (for example needed for waterkiing or wakeboarding) you may consider a 4 blade design. This will give more acceleration but will go at the cost of top speed.

[jonp]

I had a Honda 20 on a little aluminium boat which planed our family of five and the dog without any drama, far less drag on a relatively flat bottomed boat.

In most cases prop manufacturers will recommend you stay with the size prop the manufacturers recommend and simply chose the pitch to suit the load.

In most cases an aluminium prop will give a higher rpm than a stainless of the same size and pitch. Most prop adjustments are at 2 pitches at a time.

I had my current boat so loaded at the start of a 500km trip due to camping gear for 4 people, fuel and water of over 300lt and of course food, that I had to drive down the face of swells to get to planeing speeds and then alter my course. Choppy seas helped break water surface tension giving me better speed once up and running. By the way this was using my smallest pitch prop for the start of the journey, the run home from the 80km offshore islands was done on a 2 pitch great prop.

I've owned many boats over the years, most of which have been wrongly setup by the manufacturers. Most have the outboards mounted two holes to low and propped wrong. This is done by manufacturers for the reason that most people don't fully understand trim and handling. Every boat I've bought has improved greatly simply by talking with solas props about what I want to achieve from my outfit and what current prop I have and what rpm it's maxed out at. Solas have managed to get every prop to do what they've claimed first time around for me, not that it matters as they offer free replacements if they are slightly off the mark.

[jonp]

To go with a 4 blade you will need to drop pitch by quite a considerable amount. I was advised strongly not to use one on the little Honda by solas, however I did buy a 4 blade stainless from solas for my Honda 90.

[Locozodiac]

If OP plans boating with 3 aduts, 3 kids and doggy go for a OEM 8 pitch prop, would advise to buy an induction tach install it right and check the wax wot rpm achieved on flat water cond as swill be loaded for that water excursion.

It's imprudent to play with less pitch props without an installed tach, doesn't matter if counting with a musician ear that can tell at which max wot revs the motor is revving at.

Anyway you can always send the 8 new prop to a prop shop and have it repitched +,- half size (0.5 pitch) to increase/decrease wot rpm lightly if in pursuit for motor to rev towards max wot rpm range factory stated.

Happy Boating

[Stigomery]

Originally Posted by Fenlander

Of course much depends on the actual weight of Stig

This is getting personal...

Originally Posted by Fenlander

Of course much depends on the actual weight of Stig and crew. The description of 2 adults, three kids and a dog could equate to anything between 32 and 55+ stones.

So, me, my crew and our cargo equates to approximately (last weekend):

377kg or 59 stone 5lbs


So, me, my crew and our cargo equates to approximately (in the summer):

322kg or 50 stone 9lbs

[jeffstevens763@g]

showing a four blade prop 15 showing the same for info


https://www.ebcmarine.com/honda-15hp...stroke-bf20shu

[Locozodiac]

Stigomery,

Do you guys happen to boat naked during summer LOL!! If that combo would be mine, would prop it right for motor to run towards max wot rpm range with 377 Kg, throttle bit less when with 322 Kg or motor will overrev slightly more, applies best when running at max throttle grip.

Happy Boating

[Stigomery]

Originally Posted by Locozodiac

Stigomery,

Do you guys happen to boat naked during summer LOL!!

HAHA...

No...

...different children and adults... one less adult, but the other one has gained 30kgs



(3+3+D last week)
(2+3+D in summer)