Barrelback 19 planing

[Lucion]

Just finished my Barrelback 19 and am in the process of dealing with issues. I have a Mercruiser 120 HP motor and looked online for performance expectations. It appears that the optimum performance would be 35 mph @ 4000 rpm. I am getting 18 mph @ 2000 rpm. The prop is 12 x 13 CUP. Not coming up on plane at max power. Would trim tabs be the answer?

[Roberta]

You may be over propped for that engine. Are you running 1:1 gear ratio in the transmission? Try a smaller diameter or less pitch if you can borrow one. You should be able to get maximum rpm from your engine with the correct prop.

Roberta

[Bill Edmundson]

With 120 hp you should be able to get to almost 40 mph. I run a 115 hp diesel with a 13x16 prop and 1.23 reduction. I get 38 mph in salt and 39 in fresh water. You should get about 1 mph per 100 rpm.

Bill

[kens]

I'm running that engine in my Double Eagle, maybe I can help you.
My boat is 25' and 8' beam, at 15mph I'm on plane. that engine will push me to 27mph, loaded, on a good day.
You should be up also at 18mph.
That engine doesn't make 120hp either, it is more realistic about 90.
Even at a lower hp expectation, you should still get in the mid 30's.

I threw some quick numbers into a calculator and got a 10x11 (no cup) prop with a 1:1 gear.
It is way way way to early to even discuss trim tabs. tabs is never the first answer, especially on a inboard, and a new build.

here is a decent calculator, throw your boat size into it and run it about 90hp, see what you get
https://www.vicprop.com/planing_size.php

and,,, pictures ! pictures! We Love pictures !!

[Lucion]

Thanks for the responses to my issue. I didn't mention that my output transmission ratio is 1:1. The consensus opinion seems to be a smaller prop with no cup. I don't know where I could borrow one but I'll hit the shops tomorrow and see what I can find.

[kens]

Hi,
Which 120 Mercruiser do you have?
the 2.5L or the 3.0l ?

120 mercruiser was available in different configurations, which engine you got?

[Hercdrvr]

Do you have a picture of this 4 cylinder engine in your Barrelback? I’d like to see what the fit looks like.
Matt B

[Lucion]

In response to the comments made over the last couple of weeks.....The motor is 2.5 liter.
Don't have any pictures on my tablet but will download some to show how the motor is mounted.
Anyhow the reason I am back on the forum is that I found a 10x11 no cup prop from a salvage dealer on EBay. I received it today and mounted it in no time but was instantly disappointed. The prop hit the bottom of my boat. I called the dealer and told him the problem and he said that it was a sailboat prop and not an inboard prop. The prop was stamped by the manufacturer with 10x11 however it measured like sixteen inches across. What is the deal? What do I have to say to get the correct prop. In the add it didn't mention anything about being a sailboat prop and I am far to ignorant to know what is what. Help.

[kens]

Hi,
Can you post a link to that ebay listing?
this may help.
Anyway, sailboat auxialiary engines are also inboards, different yes, but still inboards.
Sailboat props have a long narrow looking blades to them.
At any rate, a prop marked 10x11 would be 10 diameter and 11 pitch, no matter the shape of the blades, no matter inboard, outboard, sailboat

Please post some pics of your build

[Lucion]

The listing on EBay for the propeller is 283567365721. Listed as "Ellis bronze three blade RH propeller 10x11 with 1" shaft". The prop in the picture is the one that I received. It has the magic marker writing on it. I just figured it was mislabeled at the manufacturer.

[Roberta]

Obviously the listing was incorrect. Contact the vendor and return it for a credit and try another source if that vendor can't supply the correct prop.

Roberta

[kens]

what is the measurement from center of hub to a blade tip?

[Lucion]

I attached a photo of the questionable prop. It measures eight inches from blade tip to center of the bore. The other images are of the finished boat and the initial motor installation.

[Rich Coey]

That is a right hand prop. Is that what you need?

[kens]

That looks like a 1:1 Velvet Drive?
How did you get a R/H wheel for that set up?
Because I never heard of a R/H rotation 2.5L engine.
I only know of those being standard rotation.
Do you actually have a reverse rotation 2.5L engine?