1971 F26 With Outboards

[Sea Ya]

Hello. Do you guys think my boat would move at a decent speed with a single outboard say a 250hp on the back. Has anyone put single or duals on your boats. I am looking at a little more up to date drive and reliability. I have had great luck with the outboards here in the warm waters of the gulf.

[Sea Ya]

I can't seem to get my boat right with the Ford. And I do not like the Chrysler.
I figure with the weight reduction and the price of outboards here I will be good. I have a 15 x 8 on my boat and I easily turn 5000+ rpm at like 19mph I almost put it up for sale Today I spent too much money already. Any thoughts???

[rossjo]

Sounds like a lot of work ..

Why not just throw a Ford 390 truck engine in it? Lots of torque = big prop . You might be able to turn a 16x20 for upper 20 knots !?

I have a 26 Chaparral express fisher, with a new Mercuruiser 454. It has a few performance mods, and a Bravo1 outdrive. It turns a Mirage 14.5x23 prop for offshore duty and a Mirage 14.5x25 for running around at 50+ mph!

[Sea Ya]

Sounds like a lot of work ..

Why not just throw a Ford 390 truck engine in it? Lots of torque = big prop . You might be able to turn a 16x20 for upper 20 knots !?

I have a 26 Chaparral express fisher, with a new Mercuruiser 454. It has a few performance mods, and a Bravo1 outdrive. It turns a Mirage 14.5x23 prop for offshore duty and a Mirage 14.5x25 for running around at 50+ mph!

How far from the bottom of the hull should the top of the prop be? I could go to a 17" x 15 pitch.

[rossjo]

There is a lot of theory on tip clearance. 15% of diameter is recommended min to reduce noise and turbulence.

I'm running 17" dia x 20" pitch (1:1 Velvet Drives) on my F32. It runs about 30mph WOT now (GPS average fior tide). This calculates to about 11% tip clearance. This is pretty minimal, but the Trojans don't provide a lot of room for larger diamater props, and the stock 1.25" dia shafts wouldn't handle more anyway.

I see you have a 460 Jet drive in another boat. A 460 would be great in a 26! Tons of torque! I run a Quadrajet on my 454. The Qjet is a spreadbore, meaning it has small primary bores (for efficientcy), and huge secondary bores (wide open). The Carter AFBs (Aluminum Four Barrel) carbs (as well as all Holleys) found on most older marine engines are square bore - meaning primaries and secondaries are all te same size - less efficient at low speed. Nothing extra at wide open. Somewhat simpler, but less efficient. Bottom line - I get about 3mpg offshore in my 26'/454 boat - yet run 50mph+.

Since you can't run a large dia prop, be sure to use about a 1:1 ratio if you change engines. A 1.5:1 ratio would increase torque at the prop, but would force you to use a largerr dia prop which won't fit ...

If you REALLY want to get crazy, pull the engine, stuffing box, struts, rudder, etc. and put in surface drive shaft just where the bottom and the transom meet, put a rudder off the transom, and run a big prop on tee surface ! I'm dying to do this someday. I almost bought a 42' Harley Superstar with twin 415HP Cats that ran 44knots using surface props!

[chucka]

How fast do you want to go? The F-26 is not a speedboat. She is pretty comfortable up to around 15 knots, but these boats are very wide for their length and have a small rudder. My F26 had a tendency not to want to travel in a straight line, especially in any kind of following sea. I put in a lot of work, extending the keel and upgrading to a larger rudder, which improved tracking stabilty a lot, but she still wanders a bit in a following sea. I think it would be nuts to spend a lot of money loading an F-26 up on horsepower, even more so, now with fuel prices as they are. I'm satisfied with comfortable economical cruising at about 12 knots. Tha't my 2 cents.
Chuck

[Sea Ya]

I see you have a 460 Jet drive in another boat. A 460 would be great in a 26! Tons of torque! I

That motor is over 500 hp. That would be insane. Put the Jetdrive in as well.

[Sea Ya]

How fast do you want to go? The F-26 is not a speedboat. She is pretty comfortable up to around 15 knots, but these boats are very wide for their length and have a small rudder. My F26 had a tendency not to want to travel in a straight line, especially in any kind of following sea. I put in a lot of work, extending the keel and upgrading to a larger rudder, which improved tracking stabilty a lot, but she still wanders a bit in a following sea. I think it would be nuts to spend a lot of money loading an F-26 up on horsepower, even more so, now with fuel prices as they are. I'm satisfied with comfortable economical cruising at about 12 knots. Tha't my 2 cents.
Chuck

Not trying to do any land speed records. But to get passed by a sailboat is not fun.

Wouldn't twin outboards spaced out help a lot with the wandering?

[rossjo]

HA! The Jet Drive would be cool (and give you great clearance inthe creeks), but not very efficient.

A stock 460 isn't 500HP - more like 300HP, which would solve your problem easily. The easisest, cheapest, most realistic solution would be a used Merc Crusaderr 7.4L (454) - cheap, torquey and plentiful.

A larger rudder would be a good idea as well.

[prowlersfish]

5000 plus rpm ?? you need more prop . plane and simple .

[Sea Ya]

5000 plus rpm ?? you need more prop . plane and simple .

Got one ordered.

[Sea Ya]

HA! The Jet Drive would be cool (and give you great clearance inthe creeks), but not very efficient.

A stock 460 isn't 500HP - more like 300HP, which would solve your problem easily. The easisest, cheapest, most realistic solution would be a used Merc Crusaderr 7.4L (454) - cheap, torquey and plentiful.

A larger rudder would be a good idea as well.

Hmm put my race boat setup in and see what happens. I wander what mph I would get with the 510 HP big block and the jet. I would pass all but the gas station.

[rossjo]

15x12 would be my next try - 1.25" shaft?

[Sea Ya]

15x12 would be my next try - 1.25" shaft?

I think 1". I will have to measure. Would going from 8 to 12 pitch be that diff?
I get only a little bite with the 15 x 8. LOL I tried a 13 x 13 and it was a joke.

[rossjo]

Going from 8 to 12 pitch would be HUGE! 50% more pitch should give you 25-30% more speed if your engine can pull it. Cheap to try (esp. for propo on ebay).