4 blade vs 3 blade props, pro's/con's

Have any of you guys replaced a 3 blade prop with a 4 blade to lessen a boats tendency to lose speed on the back of big swells ?
THT seems to rave about the positives of better grip in the water, better hole shot and maintaining boat speed with the loss of a couple of knots on the top end being the only negative, maybe they don't operate in the same conditions as we experience in the southwest of WA as a few guys I have spoken to disagree and recommend going from an ally to SS.
First hand experienced opinions ?


z00m's picture

Posts: 852

Date Joined: 10/05/14

Size

Thu, 2017-03-16 07:59

What size boat and motor?

Losing momentum on the back of swell is usually a product of not enough torque.

I changed 3 blade to 4 blade on my old boat with twin 5.0 v8's but went with a modern mercury aluminium 4 blade that wasn't very expensive and they worked really well giving the old girl good balance. 

squidvicious1's picture

Posts: 498

Date Joined: 22/07/10

 SS has less flex,4 blade has

Thu, 2017-03-16 18:13

 SS has less flex,4 blade has more bite and lower plane speed,can't go every where flat out .ive tried ,we don't live in a no wind country.

Posts: 39

Date Joined: 23/11/14

4 blade props

Thu, 2017-03-16 22:36

 Great for inrteased bow lift ,especially on cats, better bite no cavitation, lower revs but much better  for fuel economy you do sacrifice top end speed. I run a merc sst 17 inch 4 blade on my opti 200hp much better fuel economy and performance than the 3 blade sst.

pelagicyachts's picture

Posts: 628

Date Joined: 23/02/11

100% - when our previous boat

Fri, 2017-03-17 07:49

100% - when our previous boat was in charter we changed from 3 to 4 blade props (twins -counter rotating) and we lost 2 knots off top speed but could hold a 22-23knot cruise at same rpm as we were only getting 20ish prior- not very often you run at WOT so worth it in my books

Posts: 17

Date Joined: 10/12/15

 i had a 6mtr sea farer

Fri, 2017-03-17 09:00

 i had a 6mtr sea farer victory with a 200HP HO etec messed around with a lot of props on it and found the SOLAS 4 blade 17" was the pick of the bunch let me plane at alot lower speeds a would hold revs more consistantly while going over big swells rather then drop of plane at lower speeds wich the 3 blade did . Having said that i still think it depends on each boat and motor configuration as my current boat has a suzuki 250 and runs great with factory prop havent even thought of messing with it.

Posts: 44

Date Joined: 14/05/13

Seafarer

Fri, 2017-03-17 12:17

Bit off topic mate but why did you get rid of the Seafarer? Looking at new boats around 6m and they are on the list.

Grey Ghost's picture

Posts: 144

Date Joined: 12/10/15

For Sale

Fri, 2017-03-17 19:50

 I've got an old Seafarer Ventura 18 foot for sale with an Evinrude 140hp 2-stroke 4 sale. Needs some loving - I forgot about the boat when I got my BarCrusher 670HT

Don't really want to sell it because she's a good looking boat but it's wasting away at Seasport Marine :(

____________________________________________________________________________

 "Grey Ghost",  670HT Barcrusher with 150 Yamaha, based at Cockburn PBC.

Posts: 44

Date Joined: 14/05/13

PM sent

Sun, 2017-03-19 08:32

 PM sent

Coastrunner's picture

Posts: 89

Date Joined: 25/10/14

Thanks for the information

Fri, 2017-03-17 12:38

Boat is a 2016 BC 575C with maximum rated Hp, 115 Suzuki. I'm not actually having too great a problem with dropping boat speed, as long as your on and off the gas in the big swells, 17 x 14 x 3 prop and it will hit the rev limiter lightly loaded so its propped about right. The raves on THT just got me thinking, I could do with a spare prop,so what would I buy to put on and keep the ally prop in the boats tool box. Don't see many 4 blades around down here, haven't received a reply from my on line enquiry to Solas.
Cheers.

Posts: 17

Date Joined: 10/12/15

 in reply to the post

Mon, 2017-03-20 06:14

 in reply to the post enquiring about the sea farer victory i only sold it due to wanting a bigger boat , it was an awsome boat best 6mtr boat i have been in as far as ride goes they are very heavy as they are running a decent thickness of fiber glass throughout hull and i would recomend them strongly to anyone looking for a 6mtr glass boat .

Posts: 44

Date Joined: 14/05/13

Thanks

Mon, 2017-03-20 12:23

Thanks for the info mate