Prop Size Dilemma?

[bud37]

I have an idea the shafts are 1 1/2".....gonna add something to my previous comment about the handling.....our boat handles fine ,bow is just a little loose , but easy to deal with once you know.... perhaps a little different hull than the earlier ones......

[mjk1040]

The earlier Mariners had like a half tunnel the props sat in, they may have lessened the tunnel and put more of the prop in the water. Now the 355 or 356 hull design has no tunnel and the full prop is in the water? Just a theory and thought. Mike

[waybomb]

87 Mariner, no tunnels, small keel, I don't have this wander y'all are taking about.

My buddy had a32 montego years ago. I did not like driving that boat. I think it had this wander you are speaking of.

[TonyC]

Source of the post I have a spare set of 22 x 22 x 1 3/8 you could try if you want.
I'm almost next door to Pier33.

Thanks Waybomb for the offer. Unfortunately, our shafts are 1 1/4".

TonyC

[TonyC]

No tunnels on our 98.

TonyC

[SanJuanDreamer]

My 98 Mariner is swinging 20x20 with 454xli on 1 1/4 shafts.

Good post as my Mariner likes to wonder at slower speeds, thought it might just be me...sounds like that's the design.

[mjk1040]

I was referring to a 1986 32' Model. So you are right it is haul style design and not a lot of keel. Mike

[bud37]

Source of the post All,

Pulled the props on our 1998 350 Mariner. Prop shop clean and scanned and told me that I could get another year or so
out of them after a tune-up. However, due to age and that they are brass, should not expect much more life out of them.

They were concerned about the props and boat configuration. Current props are 4 blade, 20 x 23. Boat has twin 350 MAGs MPI at 300 HP. with V-Drive 1.5:1 ratio. They tell me that the "number" crunching suggests that we should use 4 blade, 20 x 21. They called and did confirm with Carver that the boat came with the props that I took off. The prop shop asked what my WOT RPM is and, while I did open it up a couple of times it was not for a long duration. I believe that the tachs were over 4000 but by how much I do not recall.

We rarely cruise more than at plane ... around 3000 - 3200k. What can be a problem and is a concern is at low RPM while docking. We need to fight a current and wind changes. With the current props the boat responds sluggishly at best without adjusting the throttles (which I prefer not to do while docking). The way I understand prop and prop design, the 20 x 21 should provide more thrust at lower RPM's providing better response while docking.

Any thoughts on this? Should I pull the trigger on the suggested new props (brass and other alloy combination at $3100 for both) or go in a different direction. We love this boat and plan to keep a long time. Thanks!

TonyC

Tony another thought here, if those props you have are original at 20x23 then the shop can knock them down to 20x21 ,as I understand it you can go up or down 2 pitch numbers, not quite the same as new 20x21 ( not sure what the cup might be), ask your shop about that if that would be something you might want to do.......

[jswampy66@yahoo.com]

hello everyone i was wondering what size prop you guys use on a 396 carver with 2 inch shafts and cummins 370 6bta thank you for kind replys ive never gotten close too 2400 ive put alot of hours at low speeds great loop and coastal cruising hudson and sound have a great night all

[waybomb]

You might want to start a new thread.