4 blade vs 3 blade props, pro's/con's
Submitted by Coastrunner on Thu, 2017-03-16 07:34
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
Posts: 1086
Date Joined: 10/05/14
Size
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
Posts: 821
Date Joined: 22/07/10
SS has less flex,4 blade has
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.
squalis
Posts: 106
Date Joined: 23/11/14
4 blade props
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
Posts: 1301
Date Joined: 23/02/11
100% - when our previous boat
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
Wayne77
Posts: 59
Date Joined: 10/12/15
i had a 6mtr sea farer
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.
Mooseknuckle
Posts: 108
Date Joined: 14/05/13
Seafarer
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
Posts: 183
Date Joined: 12/10/15
For Sale
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.
Mooseknuckle
Posts: 108
Date Joined: 14/05/13
PM sent
PM sent
Coastrunner
Posts: 414
Date Joined: 25/10/14
Thanks for the information
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.
Wayne77
Posts: 59
Date Joined: 10/12/15
in reply to the post
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 .
Mooseknuckle
Posts: 108
Date Joined: 14/05/13
Thanks
Thanks for the info mate