1987 F36 Tri-Cabin - prop sizing

[tdogg]

Hi All,

First post. Looking for some help on the prop sizing for my boat.

Below is the information for my Trojan F36 Tri-Cabin

the Max RPM I believe should be around 4400

main use is Day and distance cruising. Looking to get more efficiency and quicker to plane performance

can you let me know if the existing props are good for it and any thoughts om a 4 blade upgrade.

TRANSMISSION(S): Borg-Warner Velvet Drive MODEL: 10-17-008
DRIVE (DIRECT/V): Direct Drive RATIO: 1.91 : 1

SHAFT DIA: 1 3/8” SHAFT MAT’L: Stainless steel

Existing props:
3 blade Bronze – 20 LH 15
3 blade Bronze - 20 RH 15
Both propellers are Michigan Dyna Jet

engines:

ENGINES (#): Two MAKE: Crusader MODEL: 350 CID - V-8 PORT ENGINE HP.: 270 ROTATION: CCW STBD ENGINE HP.: 270 ROTATION: CW

[prowlersfish]

May I ask what rpm you are getting now at WOT ?

[tdogg]

I believe it is around 3800.

[prowlersfish]

Sound like your over propped , hopefully another try owner will chime in with what they have

[P-Dogg]

Tdogg? Where'd you get the idea for that name???

And the other day, some tricabin owner named Perry showed up. Go figure. But I digress....

I agree with Prowlersfish that 3800 seems a little low, I get 4k+, but don't recall exactly (and won't be able to check for a couple of months). I have the same engines as you, but don't know prop size off-hand either. Perhaps Aaron Bocknek could chime in. You might try PMing him.

And welcome to the forum! How about a little background on yourself?

[tdogg]

LOL P-Dogg...

Thank you for the info, I will ping Aaron Bocknek

I live north of Toronto, this surprisingly is my first boat. Go big or go home is very true in this case.

We bought the boat last July and have done a few trips including locks through the Trent Canal. Very pleased we came across the Trojan, love the layout. It fit the criteria we set for a Boat and exceeded it.

I've ordered an UltraPlatforme Swim Platform (made in Quebec) to expand and increase usability of the back. It was the key upgrade for this year. Props would be nice as I want to do some long distance trips

Cheers

[P-Dogg]

this surprisingly is my first boat

Mine too. I went from 13' long to 13' wide. Of course, I chartered and operated other peoples' boats. Tricabs are the most awesomest boats ever, if fishing is not your top priority and your boating budget is half the price of a luxury car.

[tdogg]

Totally Agree P-Dogg.

Love the TriCabin. Surprisingly easy to maneuver, I picked it up after a 45 min trip out with the head of engineering at our Marina. They have been awesome.

I didn't realize how much I would love being on the water.

[tdogg]

Hi, just wondering if there are any other Tri-Cabin owners that wlcoukd share their prop selection and power configuration.

3 blade or 4...any efficiency increase?

[Misty]

I have a tri fly with 20x 19s. Twin Chrysler 400s.

[tdogg]

Hi Misty,

Thank you for the response. Is your tri-fly a 36'? Is it 3 or 4 blades?

I'm getting my props tuned and cupped, to see if it increases performance. It will then allow me to test proper WOT, Planning speed, etc to get a base line.

Then I'll determine the cost to efficiency benefits for a 4 blade prop

[Barrie]

Hi tdogg
I have a 36' Tri Fly like Misty, and like his mine has 400 Chryslers with 4 blade 20" props

[tdogg]

Hi Barrie,

Thank you. Do you know what the pitch would be?

How do you like the 4 blade Props? Did you have 3 blades before? If so did you notice a big difference?

For Misty, you and others:

Any info on the your RPMs for cruising on plane? WOT? Hull speed? GPH?

Have not seen much 36' info on this site, would be good to document. We are in winter storage, once I get the boat back in the water, I'll upload some pics, and provide my findings with the tuned props

Cheers,

Tony

[prowlersfish]

Just remember your tri-cabins are not a like at all drive train wise . One is mid engine straight inboard the other rear with V-drives, Chevy small block vs big block Chrysler

[tdogg]

Very good point. Think this would be valuable info in general. There will definitely be differences. Drive train, engine all would need to be factored.

I'm still hoping someone has a Tri-Cabin and can share some of the info, as the it would directly help me