Question about prop selection

[quackaddict1]

Hello all,

It has been a long time since I have posted here but a new boat has brought me back from lurker to poster.

I recently purchased a lightly used 2005 Crestliner 1600 angler side counsel with a 2005 Mercury 60hp 4stroke EFI.

I recently spent 5 days fishing at the cabin and have a few issues I would like to resolve around performance.

First some specs:

Mercury 10.5x13P Prop (aluminum)
According to the dash mounted tach and a GPS for speed:

Just me with no livewell and 3/4 tank of fuel: RPM's to about 5600 and 33 mph in ideal conditions. Gets to plane relatively quickly.

Add another person and a 25 gal livewell, 5300 RPM and 29-30MPH, takes a while to plane.

With any load, the boat will porpoise if I trim up very much.

The motor cavitation plate is dead even with the bottom of the boat.

Issues I would like to resolve:
Improve hole shot
Reduce or eliminate porpoising
If possibly increase top end a bit.

I am almost sure I can raise the motor at least two holes, I think it is to low. I plan on doing this this weekend and delivering results.

What prop and pitch should I purchase? I am inclined to go stainless if I can figure out which one I need. I have been looking at the following:

Turbo Hot shot in 10.5 x12 or 10 1/8 x 12 (leaning 10 1/8 to try and cancel out some of the increased bite and reduction in RPM's reported on the internet)

Stiletto Triad II 10.5 x12

Hustler aluminum in 10.5x12

What direction do you think I should take?

 

[steelespike]

Re: Question about prop selection

I like the idea of the Hustler al. high performance prop,But;
their performance seems to be all over the place with across the board improvement on one boat and resuits that don't even make sense on another.

 

[quackaddict1]

Re: Question about prop selection

Is there another aluminum prop that has the same characteristics but has a better track record? I read the same thing, I almost ordered one in 12 pitch before I read into them more.

 

[Texasmark]

Re: Question about prop selection

I have been boating many years as a weekend recreationalist. I am not professionally associated with marine mechanics.

I feel that once the anti-vent plate is above the transom/water flow from beneath the transom, the opportunity to porpoise is severely reduced, as is the ability of the trim to lift the bow....i.e. enhancing the porpoise initiator. BTDT

Boat velocity has a significant impact on porpoising for a given set of conditions. You can be at WOT and everything is in order, cut the throttle a few hundred and all of a sudden the mammal comes out. To put it back to sleep, you need to either speed back up, or tuck in your engine (trim down till it quits).

You may be able to jack your engine up a hole and solve most of your problems. Jacking up a hole means carefully pulling your transom mounting bolts out, and with your skeg on the ground (concrete floor preferably) use the tongue jack on your trailer to raise the bow of the boat, thus lowering the transom until you can get the bolts in the next lower holes on the engine mounting bracket (to the transom)..marine sealant on the bolts/transom interface preferred to keep the water out of the transom; especially if it is made of wood/wood core.....may want to secure the engine to the boat with some rope (line) if doing it alone so the the engine doesn't get away from you.....have done it several times alone up to 125 hp. Once you have done this you will be amazed at the difference in performance.

With the engine at it's present height, the anti-vent plate acts as a shovel in digging the transom into the water and the angle of dig (trim position) is extremely critical to prevent porpoising. Once you get the plate above the water, boat trim is more of an issue of engine thrust direction and is much smoother, and much easier to control.

Your performance numbers for your rig sound good to me. I wouldn't change a thing till I got the anti-vent plate up above the water flow as I said. One notch may do it (3/4") or it may take 2....hopefully one will do it.

Planing out with a load, if WOT parameters are where they should be, benefits from having the engine tucked all the way into the transom....as far as the tilt pin will allow and it could be in the last hole (closest to the transom).

Adding another body (person) to a 16 ft boat with a 60 hp engine is A BIG DEAL and I think your setup handles it nicely.

Do what you said, about raising the engine....try one hole and if things improve but are not optimal, go the second hole.

Get back with the results and we can go from there.

HTH

Mark

 

[quackaddict1]

Re: Question about prop selection

Wow I never though of the cavitation plate doing that but it makes perfect sense. I will raise the motor this weekend and report back. I appreciate the reply!

 

[quackaddict1]

Re: Question about prop selection

A pretty eventfull dayon the river today.

Last night I moved the motor up two holes. It is now mounted so that I can move it up no more withotu a jack plate or redrilling holes (neither of which I will do).

New specks on the rig. Two people no live well up the river gets me 6000 RPM (pretty sure its running on the limiter) and 33mph, the hole shot with two is better than what it was before with just me in it.

Same load plus half of a livewell (12 gallons or so) coming down the river got me 36 with a few glimpses of 37, the motor is running at 6K.

The porpising effect has all but gone away, I can now trim up to about 1/4 trim (best rpm and speed) with very small amounts of porposing.

Before I couldnt trim up any without it porposing, this explains the large pick up in RPM's with two people.

So Now im pretty sure I need to increase the prop pitch or got to a stainless with better bite. I would like it to run a bit south of the limiter, especially since my test was with two people and light gear load.

Would a 13 pitch stainless get me what I want? 14 pitch alumium maybe? I hate to loose to much of the hole shot but it gets to 6K fairly easy.

 

[Texasmark]

Re: Question about prop selection

Well how bout that sports fans....grin.

Yes, you have allowed your boat to ride on the water, rather than plowing through it so you have considerably lightened the load without actually lightening it.

Depending on your feelings about running too high rpm's the standard rule is 200 rpm drop per pitch of prop as I recall........IFFFFFFF all else is the same..i.e. same identical prop from the same mfgr. with nothing changed but the pitch (and possibly a slight diameter change....usually goes along with the pitch change).

So you could go with a like prop and up it 2 inches and drop your rpm's down to 5600, or if you are actually in the limiter they may stay up higher so you will need more pitch.

If you go to SS, your performance will improve as will your efficiency by just changing metals. But SS props usually have added goodies which increase their efficiency and if cupped (usually are) give you the equivalent of an additional 2" of pitch at the higher rpm's where the cup can contribute without anything changing but adding cupping.

So, I'd say you could go to SS with a 2" increase in pitch and be absolutely dazzled by your performance. Ensure it is cupped and if you want more bow lift (less drag) get one with a "high rake" and if you want a better hole shot without sacrificing top end, get one that's ported (little holes drilled in it just below the leading edge of each blade). Iboats sells them on here. You decide what suits you.

There are Turning Point Hustler Alum. props on sale here in iboats which have some really good specs and are sale priced at $100. I have one and it is a great prop. However it is not SS and will not perform quite as well for a similar spec'd SS due to the thickness of the blades....but for $100..............I think you might try the brand and move up 2" in pitch from your current pitch....diameter approximately what you have now....not real critical.

Don't forget to come back with your results.

Mark

 

[quackaddict1]

Re: Question about prop selection

Interesting thoughts Texasmark, I have some more data to round out what I have said. I dont think the rive is an especially good place to get baseline data. Today we chased bluegills on an actual lake.

3 folks no livewell resulted in a fairly slow plane (got up just takes some time, but expected with 600lbs of people in the boat) and 6000ish RPM and 33mph. Add a 25 gallon livewell full of bluegills and 32 was all I could get out of it.

Dropped the people I was fishing with off and went and ran solo (with 25 gal worth of water and gills still in it) to see what I could get out of it. 6100 RPM and 36mph was tops before I shut it down, 35mph was real easy to get.

The motor has a rev limited at 6250, I hit it today and it just dies when it deactivates two cylinders.

With three people and all that water in the livewell, the prop seemed to break loose fairly easily, trimmed up in gentile turns and even a bit at mid rpm's. When I went solo it broke loose in the corner, despite triming in some.

If I went to a 14 pitch stainless I should drop about 300 rpms according to what I read on the internet. If I run the boat empty I am pretty sure I can get it to run north of 6100rpms, If I could make it top out around 5900 and pick up better cornering/bite/hole shot with the vents/and maybe a mph or two I think I would be in the money for this rig.

 

[Texasmark]

Re: Question about prop selection

A cupped prop will definitely help to reduce your breaking out in high speed/tight turns. BTDT

Additionally, a couple of days ago I tested my Ballistic SS with my new 1/4" port holes that I drilled (SS is tough yucko) in it to improve my hole shot without changing my WOT speed.....it wasn't ported. The hole shot improvement worked fine but what I didn't expect and can't understand...thought the opposite would happen, was that I could engage a tight turn at WOT, or go into the turn at reasonable throttle, and goose it to WOT in the turn and it never broke loose.....amazing.....and for any critics, I am not being wreckless and am not endangering anyone in my antics. I go to a smooth lake on a week day when few are out there and I play where they are not. The boat rides on a 3 stepped hull and has a wide beam. It's BIA rated for 130 hp and I only have a 90 on it.

HTH

Mark

 

[quackaddict1]

Re: Question about prop selection

Where did you drill your holes? How many? Im not seeing any props in the size range im looking for with vents.

It will take me a bit to decide which prop I wanna go with, looking real hard at a 10 1/8 by 14 turbo, gonna continue to look for some other options.

Any ideas?

 

[Texasmark]

Re: Question about prop selection

Back up a dozen roughly threads and look for one that reads something like "more ol hole shot" with a paper clip on it that I answered. I have pics there that you might be interested in.

Mark

 

[quackaddict1]

Re: Question about prop selection

Well, after racking my mind for a week I just placed an order for a Hustler 10 3/8 x14 prop. I will post the results when I get time next week.

 

[quackaddict1]

Re: Question about prop selection

An update to this story. My 14 pitch Hustler prop turned up this week and today I took her down to the river to try it out.

Two folks in the boat got me 5600ish RPM's got me 33mph on the flat water and 34 with glimpses of 35 on some chop (the slack areas of the river, minimal current)

In the current (where my last test was) downstream with two folks got 35 pretty easy with some periods of 36, RPM's in the 5700 ish range.

Upstream I got 33mph out of it in the heavy current, rpms were in the 5500-5600 area.

Solo was where I expected to pick up the most, and I was right. Upstream got 35mph out of it, downstream I had sustained periods of 38mph. Once I got to the slack portions of the river 37 was all I could con out of it.

Thoughts on the prop.

Bites better overall than the stock prop, thou you can still blow it out in a corner if you want to.

This prop seems to have completely resolved the porpoising problem, now I can trim to over 1/4 way on the guage and it will run smooth.

The hole shot is slightly slower than the 13 pitch with two people, this prop has no vents. With one person it snaps up just like the 13.

Mid range cruising has improved, I can cruise on plane at lower speeds than with the last (3-4mph less is all)

I honestly think the motor is still to far in the water, I think I could get more out of it with more height, but that cant happen the way the boat is set up now.

I am happy with what I have now for performance and will be keeping the hustler. I have accomplished all of my goals and have a very good performing boat considering HP and size.

Now on to sonar, a paint touch up, and some new lighting!

 

[Texasmark]

Re: Question about prop selection

this prop has no vents.

Interesting. Wonder where they decide to port or not to port. Maybe they only port the larger props, like those for 4.25 and 4.50 gearboxes.

 

[quackaddict1]

Re: Question about prop selection

A good question, since they advertise vented props, I assumed it would be vented. Maybe just in the larger pitches?