Outboard Propellor Pitch Question

[PEJ]

I found out the hard way that it gets a bit shallow in Porto Colom and now I need a new prop for my outboard. I am wondering whether to go for a straight like for like replacement or should I take this chance change the pitch.

The outboard is a Suzuki DF30ATS and the tender is a 2.65m Walker Bay. The current prop is a 10 1/4 with a 13 pitch.

I would like more grunt to pull inflatables behind it. Can anyone tell me if changing pitch will help with this?

 

[wipe_out]

I guess the only issue is a potential of over revving at WOT with a lower pitch but it would certainly give more power at lower speeds to get going.. Another possible option would be to switch to a 4 blade (if available and with the appropriate pitch adjustment) which would give you more "traction" on the water..

 

[rbcoomer]

+1 for extra blade if available - might only be on bigger motors though...

 

[QBhoy]

Jeez....if I'm reading this right, that's some size outboard for a 2.65m boat !
Probably difficult to determine, may not have a rpm gauge, but any idea of current rpm, gear ratio and gps speed ?
Need to know desired rpm range too. Then a good assumption can be made.

 

[PEJ]

Jeez....if I'm reading this right, that's some size outboard for a 2.65m boat !
Probably difficult to determine, may not have a rpm gauge, but any idea of current rpm, gear ratio and gps speed ?
Need to know desired rpm range too. Then a good assumption can be made.

Yes it is pretty big but others on here have put 40HP outboards on similar dinghies! I particularly wanted it to go fast and it does!

There is no rpm gauge or gps on it but I reckon it will do 25 knots or more.

 

[QBhoy]

My goodness...I'll bet she is doing more than 25 knots. Must be a howl and good fun.
I recently sold a wee valiant 3.0m with 10hp and remote console....she did 22mph gps and was an absolute howl to drive.
You'd think your set up wouldn't need much adjustment to get the blood flowing ?
Must be rapid !

 

[Bouba]

It would scare me to death, you would probably have to have a long tiller handle so you can drive it sitting on the bow tube with you legs dangling over the front. My 2.60 has a Honda 2.3, and even though it's probably the best motor for a tender in the world I'm planning to go electric (as soon as I install a genny)

 

[Portofino]

It would scare me to death, you would probably have to have a long tiller handle so you can drive it sitting on the bow tube with you legs dangling over the front. My 2.60 has a Honda 2.3, and even though it's probably the best motor for a tender in the world I'm planning to go electric (as soon as I install a genny)

We have had a mini Kota + 60ah bat on a 2.4 M for the past 10 y or so .
Tender is collapse able and packs away -flat bottom in a bag -- so does not plane anyhow .
You looking at 3-4 knots --D speed only -enough to get about just ,with all the time in world .Range not an issue .
No fuel potentially a dangerous substance issues --just - plug n play and of course charging the bat is free ,shore or Geny .
Never really felt the need for a faster petrol OB .
Just pointing out they are not fast .
Looked at Torquedo ,but was 2x a small petrol price wise ,more knick-able /desirable -- did not like the lithium bat -re-charge thing --costly replacement eventually .
A 60 ah car bat is €50 sold everywhere .Mines over 10 y and still going strong -( does get used )-but as said who cares if needs replacing .
We got it because of safety with the then little kids -- I was not comfortable with em bombing around in a petrol OB Tender ,while mum and dad snoozing on the boat -- also they could "start "it if they went off doing a "swallow and Amazon " thing exploring anchorages /islands etc .

They have flown the nest and we have not bothered to upgrade and feel no pressure to either

Why are considering moving away from the Honda 2.3 ? to electric ?

 

[Nick_H]

Yes it is pretty big but others on here have put 40HP outboards on similar dinghies! I particularly wanted it to go fast and it does!

There is no rpm gauge or gps on it but I reckon it will do 25 knots or more.

Wow, I don't remember seeing a dinghy that size rated above 10hp, so putting a 40, or even a 30 on it must be bonkers. The engine must weight twice what the boat does?

Anyway, yes a smaller pitch will have more acceleration to pull skiers and ringos. In theory it could overrev at WOT, but by that time the dinghy will have sprouted wings and started flying.

 

[Bouba]

We have had a mini Kota + 60ah bat on a 2.4 M for the past 10 y or so .
Tender is collapse able and packs away -flat bottom in a bag -- so does not plane anyhow .
You looking at 3-4 knots --D speed only -enough to get about just ,with all the time in world .Range not an issue .
No fuel potentially a dangerous substance issues --just - plug n play and of course charging the bat is free ,shore or Geny .
Never really felt the need for a faster petrol OB .
Just pointing out they are not fast .
Looked at Torquedo ,but was 2x a small petrol price wise ,more knick-able /desirable -- did not like the lithium bat -re-charge thing --costly replacement eventually .
A 60 ah car bat is €50 sold everywhere .Mines over 10 y and still going strong -( does get used )-but as said who cares if needs replacing .
We got it because of safety with the then little kids -- I was not comfortable with em bombing around in a petrol OB Tender ,while mum and dad snoozing on the boat -- also they could "start "it if they went off doing a "swallow and Amazon " thing exploring anchorages /islands etc .

They have flown the nest and we have not bothered to upgrade and feel no pressure to either

Why are considering moving away from the Honda 2.3 ? to electric ?

I had a trolling motor and a big inflatable Zodiac and went all over France from lac to lac for years, we love lakes. Right now we are in a beautiful hotel in the village of Talloires over looking Lac d'Annecy, one of the most beautiful lakes in the world. The village is famous for its food and we are looking forward to dinner tonight. Tomorrow we're going to the old town of Annecy which is like a mini Venice. But not with our own boat, I lost the trolling motor and all my batteries in the big flood a couple of years ago.
The tender on my boat is a 2.6m Highfield aluminum rib, it rows beautifully (much easier than the inflatable) so I hardly use the Honda anyhow. But like you I would like to get the petrol off my boat. I'm planning on a Torqeedo, and I realize that lithium ion batteries are probably as dangerous as petrol.
Also I think with the easy start stop of electric I would use it more and actually go farther, plus it's quiet, another bonus. I guess also it would make the genny feel like it's paid for itself, in a man maths kind of way. Also my wife has one of the stand up paddle boards that you peddle like a stepper in a gym, brilliant things, she loves it and goes fast and far in it. But she would like to explore even further on it but only if I accompany her with the tender. But she doesn't like the noise of the outboard so she is really the driving force in the switch to electric.

 

[PEJ]

Wow, I don't remember seeing a dinghy that size rated above 10hp, so putting a 40, or even a 30 on it must be bonkers. The engine must weight twice what the boat does?

Anyway, yes a smaller pitch will have more acceleration to pull skiers and ringos. In theory it could overrev at WOT, but by that time the dinghy will have sprouted wings and started flying.

As with a lot of boaty things my inspiration for the choice was Hurricane - Have a look at this: http://www.ybw.com/forums/showthread.php?461501-Walker-Bay-Ribs-UK-dealer&p=5778127#post5778127

Scroll down to the video of his 40HP on the back of a Walker Bay pulling a water skiier.