V-4 omc on 13r

[JETMORE]

Anybody ever run a 140 johnrude on an old 13r? Curious if it is a handling nightmare and what to expect on top. I assume you can't really run that boat at 80mph, but you could prop it to have awesome accelaration and run 65 or so.


Any thoughts?

 

[Mr. Scary]

We sold one of our Critchfield/Rapid Craft cyclone 13' boat (hull similar to a 13R) and he put a CrossFlow V4 on it for drag racing. He said it did fine. It was a lot of power and it would twist the boat over pretty hard when it took off, but he said it was fine. I don't remember what he said it ran....

 

[loop]

I was wondering the same thing
135/140 johnrudesare cheap and durable. 90's and 115's are even cheaper
I would think if you were to lose some weight off the motor and shift some weight around in the boat it would be a super fun ride.
imagine it with a smaller diameter gearcase and about a 12"mid....hmmmmm
I think I may go this route myself. Was looking into adapting a Rotax 951 motor (130hp) to a custom built mid but the v4 would be much cheaper and easier.

 

[jmccauley]

Unsuited. Not safe, won't handle (the 85 Mercury is already too heavy), won't be much faster than a good 3 cyl. looper, which is ideal. For the heavy V-4 you need a 15' or 16' boat. A good 1975 75 with milled head (.080") and the right prop (made by me) will break 71 mph on a 13' if the pad's about 7" and the bottom's straight and not flexing. Forget running a heavy motor on that boat, it won't work!

Anybody ever run a 140 johnrude on an old 13r? Curious if it is a handling nightmare and what to expect on top. I assume you can't really run that boat at 80mph, but you could prop it to have awesome accelaration and run 65 or so.


Any thoughts?

 

[jmccauley]

Top speed of a V-4 in JP class (15-16' Allison) was 73mph. The 13' would not run much faster and would be a nightmare to handle with the cow on the back. To get into the upper 70s with a V-4 you'd need the racing model with the racing gearcase. On a 15'16' Allison. The later (ca. 1978) 16' model with V-4 was the best-handling Allison that I raced, I ran the 13', 14' 16' and 20' models.

 

[loop]

Joe
Thanks for your input. Cant think of many people who could offer a more informed opinion on this matter than you. Your advice is VERY much appreciated.
How heavy of a motor can the the 13 footer handle? Is it strictly the weight or is it a horsepower issue also? I know of one in Houston thats about to get a highly modified 3cyl. It should be well above 100HP.
Mine is an earlier 1970 model with a wider pad,approx 10"wide. Its in the process of being fully re-cored and a new transom and stringers.

 

[jmccauley]

It's the weight, not the hp that's the problem. To run the heavier (than OMC 75) shortshaft Mercury 85 in GP class Paul had to make a bottom modification with Bondo to get the tail up. The V-4 with its 20" downhousing would be a handling nightmare because of both weight and height. Far more sensible would be to put an OMC SST-60 motor on the boat. In any case, the pad and turning surfaces adjacent to the pad must still be good enough not to flex, and must be straightedged. A flexing bottom will kill the speed regardless of hp.

We and others who were competitive in GP Class never ran an 85 Mercury on the 13' boat, we used the 14' model, some (Joe Burgess) ran the 15' model with success. Some few may have run the heavy 85 shortshaft Mercury on a 13' Delta or Critchfield, I don't remember anyone running anywhere near the front with a 13' boat, most others ran a 14' Hydrostream (those boats wouldn't turn). Actually, I generally added weight and stepped up to run GP with my smaller and faster OMC 75, and was always competitive.

Do I know you?!

Joe
Thanks for your input. Cant think of many people who could offer a more informed opinion on this matter than you. Your advice is VERY much appreciated.
How heavy of a motor can the the 13 footer handle? Is it strictly the weight or is it a horsepower issue also? I know of one in Houston thats about to get a highly modified 3cyl. It should be well above 100HP.
Mine is an earlier 1970 model with a wider pad,approx 10"wide. Its in the process of being fully re-cored and a new transom and stringers.

 

[loop]

An SST60 motor would be the ultimate for me but this is supposed to be a budget hot rod (thats what I told my wife). Unfortunately I'm spending WAY more on replacing every stick of wood in it than I originally planned. At least it'll be right and solid as a rock when its done. I'm concentrating on strength rather than keeping it ultra-light since its just a play boat.
The 13' I mentioned before is at Acies shop. Was John Calleys boat. It should be real strong.It belongs to Allen Robertson
Do you know when Allison went to the narrower pad? Every 13-16' I've seen has a narrower pad than mine.
A 15'or 16' was what I really wanted. Then I came across this one and figured it would be just as fun. I used to own a 15' Laser w/ a crossflow140 and to this day its the funnest and cheapest boat i've ever driven. It was Louis Collins boat that holds the JP record. I raced it in the last season that they ran JP's,1988 I think it was. Just about the time I started learning to drive and was getting the boat dialed in they pulled the plug on the class. best class ever in my opinion.
We've never met but I've heard your name ever since my first exposure to boat racing in the early 80's. I know John Calley though I havent seen him since probably the mid 90's.
Johnny probably wishes he never met me. In '89 or '90 He offerd me his Oasis to drive in the upcoming season since his scedule wasnt going to allow him to race. I gladly accepted. Long story short,I was out practicing behind my house (on Galveston Bay) Hit a rogue wave and blew a hole in the side of his beautiful boat. Johnny is such a class act. He was only concerned that I was OK.
My attempt at boat racing is something I wish I could erase from history and start over. Would have been much smarter to watch and learn for a couple of seasons rather than jump in w/ both feet like I did

 

[jmccauley]

I bought the red/white boat (the one at Acie's shop) new in 1981, raced it, sold it to John and bought another 13' in 1982. I'd widened the pad to 8" with Bondo, which was too much, the tail did not plane high enough. A 7" pad on that boat is optimal (same width as the 14' boat's pad). The 13' came from the factory with a 5" or 5.5" pad. I see John each fall, I'm in Europe each year until Aug. If budget matters then look for a 3 cyl. shortshaft 75, there are surely a lot sitting in garages but you have to find out where, they aren't advertised anywhere.

Joe

PS I let George Laycock drive the red/white boat at the NOA nationals in 1981 (with my stock 1975 75) because there was no weight limit. George weighed about 130 lb. He won. So the boat won at least one national championship.

An SST60 motor would be the ultimate for me but this is supposed to be a budget hot rod (thats what I told my wife). Unfortunately I'm spending WAY more on replacing every stick of wood in it than I originally planned. At least it'll be right and solid as a rock when its done. I'm concentrating on strength rather than keeping it ultra-light since its just a play boat.
The 13' I mentioned before is at Acies shop. Was John Calleys boat. It should be real strong.It belongs to Allen Robertson
Do you know when Allison went to the narrower pad? Every 13-16' I've seen has a narrower pad than mine.
A 15'or 16' was what I really wanted. Then I came across this one and figured it would be just as fun. I used to own a 15' Laser w/ a crossflow140 and to this day its the funnest and cheapest boat i've ever driven. It was Louis Collins boat that holds the JP record. I raced it in the last season that they ran JP's,1988 I think it was. Just about the time I started learning to drive and was getting the boat dialed in they pulled the plug on the class. best class ever in my opinion.
We've never met but I've heard your name ever since my first exposure to boat racing in the early 80's. I know John Calley though I havent seen him since probably the mid 90's.
Johnny probably wishes he never met me. In '89 or '90 He offerd me his Oasis to drive in the upcoming season since his scedule wasnt going to allow him to race. I gladly accepted. Long story short,I was out practicing behind my house (on Galveston Bay) Hit a rogue wave and blew a hole in the side of his beautiful boat. Johnny is such a class act. He was only concerned that I was OK.
My attempt at boat racing is something I wish I could erase from history and start over. Would have been much smarter to watch and learn for a couple of seasons rather than jump in w/ both feet like I did

 

[loop]

So what are your thoughts on the 10" wide pad mine has
Do you think they were built that wide because the boat was actually rated for only 30HP?
Also, it actually is a slightly rounded keel,gradually flattens out towards the stern but not completely.

 

[jmccauley]

10"pad is way too wide. The boats were rated at ridiculously low hp for
insurance porpuses only, to try to avoid lawsuits. The 14' Allison raceboat was rated for 25hp, was built to run 75 hp.

So what are your thoughts on the 10" wide pad mine has
Do you think they were built that wide because the boat was actually rated for only 30HP?
Also, it actually is a slightly rounded keel,gradually flattens out towards the stern but not completely.