10M Express what is the best prop?

[prowlersfish]

Very good sir, my limited info just showed 330 is why I question it . They have all the info.

[prowlersfish]

Sorry, I took so long to get back to you. There seems to be no record of an express with a 1.5 only the mid cabins. So most likely it was changed. Maybe repowered? So since its power train is like a mid-cabin so propping may be the same. Mid had 16x17 props you have 16x16 . You said you thought your rpm was 4400 and thats good. But I wonder why the prop shop wanted you to go to 15x15? I think the rpm needs to be verified

[RWS]

if that's the case suggest you replace the gears with the correct ratio for the express

Then install the correct props for the express

The bigger diameter wheels will result in far better efficiency, power and economy

RWS

[BobCT]

Correct, the mid cabin gears were 1.52:1. I think you have confirmed without doubt you have an express. I wonder if someone just replaced both drivetrains out of a mid cabin.

At a glance, the hulls look the same. I could someone easily making that mistake.

[Trojan10m]

Thank you for the information. From the history I know of the boat I never heard it was repowered other than one motor being replaced but not the transmission.

As you said you have no record of an Express with 1.5 ratio, I was looking at the Coast Guard approval stamp and it is 01/82. I checked the HIN and wondered if it was one of the first few out of the mold and maybe they were still in the testing time.

My HIN is TRJRB0500182-1982-333

Is there any decoding that can help tell that.

I have been working to get it in the water this week and have the props cleaned up to confirm the data points. From the data points of top speed , rpm, gear ratio, etc. can we bench test what props are better. Is there a way to confirm the prop shaft location and angle?

Thank you.

[RWS]

FYI

The EXPRESS has longer shafts and TWO struts per side

Midcabin has shorter shafts and ONE strut per side

Regardless of what's in there now you can make a choice:

smaller props spinning faster

or

bigger props spinning slower...

Attached below is the flo scan results of my 4 blade props with the gas engines before the diesel refit

Really not too shabby when one considers the actual VOLUME of this vessel.......

RWS

RWS_GAS_CHART.jpg (45.68 KiB) Viewed 10780 times

RWS_GAS_ACTUAL_DATAONLY_DETAIL.jpg (39.75 KiB) Viewed 10780 times

[prowlersfish]

I Sent the Numbers to Bob and he checked with John (John has all the Trojan records). He said all the expresses had 2.0 gears. You have the engine numbers on the plate, you could compare it to what you have now . If you can find and read them on the engines.
Not sure about your shaft placement question. Can you take and post some photos of the bottom and running gear so we can see the shafts and props? From the sides and back? Me we can pick up something. I will speak to Bob again.

RWS posted some good info. I will say his speed numbers are better the most, but he keeps up his boat better than most.

[prowlersfish]

Stay tuned mystery is solved will post tonight (on the run right now) .

[prowlersfish]

And now the rest of the story. Indeed your boat came 2.0 to 1 gears. Also, it is listed as a 335 on the paperwork. You can see on the paperwork where the number was changed. (likely a trim/color issue) . The engines also have been changed . This was a shocker to me ,She came with 270 small block crusaders . You can go 2 ways on this leave as is and play with the props ( after we know your top rpm. Or go to a 2 to 1 gear and reprop.

trojan 10 paper work 2.JPG (36.12 KiB) Viewed 10766 times

Thank you Bob and John For your help .

[Trojan10m]

Wow. That is crazy you guys still have the documentation. Thank you for being a caretaker of the historic documents.

I am planning to splash it on Thursday but I will get plenty of running gears pictures. There is only strut per shaft.

I will share the data and we can make a plan. Thank you all.

[Trojan10m]

I was able to get the boat in and get some data today.
Test run:
full load of fuel, clean bottom, 16 x 16 cupped.

Cruising speed
3000 rpm - 16 mph
3400 rpm - 20 mph
3900 rpm - 21 mph - maxed rpm

Tab down, when I raised the tabs the speed went down at cruising and max rpm.

It seems like the boat is happiest when she is heavy. Please let me know what you all think. Thank you.

[prowlersfish]

Mmmm , 3 or 4 blade ? Get a photo tach and check your tachs, should do better. I will give this some more thought

[Trojan10m]

3 blade and I have pictures and measurements of strut and prop locations. I will try to post tomorrow.

[RWS]

Mmmm , 3 or 4 blade ? Get a photo tach and check your tachs, should do better. I will give this some more thought

+1

RWS

[Trojan10m]

You are correcr the tachs are not correct, i was able to check at idle and they do not match. I will need to get another tach to test at operation.

I probably wont get back to the boat until Thursday for follow up.