Transom HP limits

And as far as the 30 mph cruise, mine goes 30, or even a little more with twin 45s with a light load. But, they are screaming at 100% throttle and you know how wear goes at 100% throttle. I will counter what the others have said, if the boat is trimmed properly, meaning the bow isn't really down much, I honestly can't really tell the difference between 20 and 30 except I get places more quickly. Bob says the top speed is about 36 with the 140 - never gone 36 and have no intentions on it, but a 30 mph cruise in PWS is pretty nice and I'd love to have it. I think you're onto something here. I'm pretty sure my 400 hp truck will go 150 mph, but I don't drive it that fast.....weird....

BTW, I think you're insurance company would have to provide valid and sound arguments for any claims stating that the 140 hp outboard contributed. In other words, just because it is there, does not necssarily mean anything. And, most claims are dings at the dock, trailer failures, or running into somebody in the marina - all slow speed things. Well depends on the trailer failure....lol....I also agree that some lawyer could have a hayday with it....I'd be willing to take that chance in Alaska. In another state, maybe not.

Quick question to anyone actually knowing: Is the 100 hp rating really just a suggestion, or is it legally binding by the USGS for a 22 foot boat? I'm reasonably sure it really it is just a recommendation on boats this size.
 
I just did a re-motor on my CD22 from twin 40's to twin 60's. Honda. I had to find documentation and proof that the HP ratings over 20' are manufacture's suggestions and not law bound. Any boat under 20' has to have an HP rating and has Federal Regulations. My insurance company said I was good to go. I think it ends up being the choice of the Ins Comp at the end of the day. Mine seemed very helpful. State Farm out of Monroe, WA. I also found a formula that if correct and all things being perfect would say the boat can handle 188hp. Yikes! Horsepower for over 20’. (6.333x22x2)-90=188.7hp No Thank You!
I didn't do the re-motor for speed, I did it for power in sketchy situations. The 60's makes it feel like a truck in 4WD. I have more control and a huge peace of mind when I'm out in the Puget Sound PNW. The waves get angry near Everett. Hunkydory's thread was the motivation for me. Peer Pressure! I'll share my data once I get out on the water more.
 
Hopefully the Administration can memorialize this conversation thread, as this topic has come up numerous times. And some responses have been rather pesky when the repower choice has exceeded the sticker on the dash.

Can the Administration save this info somewhere so it is easily accessed ? And not lost in time.
thanks
 
T.R. Bauer":2ttpnb7a said:
Nickstr-1":2ttpnb7a said:
Thanks for all the great input.
Currently I run between 17 & 22 mph and burn 4.5 to 5 gph.
The 115 hp and the 140 hp are the same block and weight. The interesting fact is they are thr same block and overall weight (428 lb). Fuel burn at 3000 rpm is actually less on the 140 hp model.

I would like to cruse in flat water at 30 mph or 26 knots.
I agree boat would be danergous at higher speeds.

Considering a transom stiffener plate, wondering if anyone has tried this.

Nick
Click to expand...

There is a CD 22 in Seward with a suzuki 140. It has been done.
Click to expand...



I’d love to cruise @ 28-30 in pws. That 5 hours round trip travel is a killer!
 
Speed is subjective and relative. Speed changes you. It actually changes time.

If you've sailed, 8 knots is good. I sailed a 61' C&C going into Villamora, Portugal
w/a small trisail spinnaker at 16 knots w/white water astern aplenty. It was
exhilarating.

I've gone 5 - 30 mph in multiple powerboats w/various impressions. I drove a
friends drag boat to about 100 mph which scared me. My deep-v 28' Saber
would do about 80 mph. It was like driving a sport Ferrai or Maserati:
responsive, sensitive, feeling like almost unlimited ability. It was a fix.
Nothing like it. Maybe a motorcycle.

Figure it out. You're on this planet called Earth. We're traveling about 67,000 mph
around the sun. Isn't this a gas? Get into the ride.

Enjoy it while it lasts. Enjoy reality.

Aye.
 
T.R. Bauer":2reheksx said:
And as far as the 30 mph cruise, mine goes 30, or even a little more with twin 45s with a light load. But, they are screaming at 100% throttle and you know how wear goes at 100% throttle. I will counter what the others have said, if the boat is trimmed properly, meaning the bow isn't really down much, I honestly can't really tell the difference between 20 and 30 except I get places more quickly. Bob says the top speed is about 36 with the 140 - never gone 36 and have no intentions on it, but a 30 mph cruise in PWS is pretty nice and I'd love to have it. I think you're onto something here. I'm pretty sure my 400 hp truck will go 150 mph, but I don't drive it that fast.....weird....

BTW, I think you're insurance company would have to provide valid and sound arguments for any claims stating that the 140 hp outboard contributed. In other words, just because it is there, does not necssarily mean anything. And, most claims are dings at the dock, trailer failures, or running into somebody in the marina - all slow speed things. Well depends on the trailer failure....lol....I also agree that some lawyer could have a hayday with it....I'd be willing to take that chance in Alaska. In another state, maybe not.

Quick question to anyone actually knowing: Is the 100 hp rating really just a suggestion, or is it legally binding by the USGS for a 22 foot boat? I'm reasonably sure it really it is just a recommendation on boats this size.
Click to expand...



When my boat was built in 2007 the sticker said 100 HP. I asked the factory if they would put on a 115hp and was told that the sticker was not a requirement for boat 21 foot and bigger. They said they would leave the sticker off of my boat and mounted the 115 on it. Six months later the new stickers said 115hp on them. At the time the Suzuki 90 and the 115 were the same motor same weight. Now the 140hp weighs less than my 115hp. I was told it was more about weight than hp.
 
The Formula one race boat weight 860# including a 400+ hp Mercury outboard; They are 20' long and 7' beam, made mostly of carbon fiber and Kevlar--I have ridden in one at 138 mph. That doesn't mean that you can just put any HP engine on any size boat.

The C Dory is just not made for high horsepower in comparison to many other boats that size. If you start looking at boats with high hp, there is a lot more structure in the transom, and support, such as stringers, transom knees, built up keels and keelson's.

When you have seen what happens to a C Dory transom when even a 115ph motor hits an underwater obstruction--It would make you perhaps re-consider what hp you put on the boat. Will the boat float and run? sure. But the practical limit for controllable speed is somewhere in the 30's. The Tom Cat is an entirely different type of boat--and with a couple of Suzuki's in the 175 to 200 can reach over 50mph and be in good control.

When we were looking at the construction of our first C Dory 25, I found that the plywood core did not go all of the way from side to side in the transom. The splash well was mostly chopper gun--and was not as strong as it should have been. As part of the rebuild process, we put several more layers of 1708 glass and epoxy both across the transom, and up into the supporting structure of the splash well.

I have a Suzuki 140 on the 18' Caracal cat. That boat basically uses the inner side of each hull as a support structure for the outboard. The load is far better spread out in that boat than in a C Dory 22. The plywood core, also extends to the outer hull where it mates to the transom, and is taken up into the cockpit structure also. The C Dory 22, uses the plywood core and the splash well--The load is better transferred out to the sides of the hull than our 2003 C Dory 25 was.

I believe that the newer 25's have the load better distributed.
 
TSTURM:
Maybe you & the other 28ers need some boat handling skill training? If you can't see the wind on the water your not paying attention maybe?
Click to expand...

I'm pretty sure I know how to handle my boat. But wind gusts do come up. Along with a lot of other things that will bite you in the ass even when you are paying attention. As an ex-coastie that flew C-130 rescues out of Kodiak Alaska, I can remember a few boats with competent skippers that would tell you the same thing! :roll: Colby
 
FYI
Check out a beefy transom plug by clicking W B Nod under my side post ID, then
"Core Sandwiches".
That 5 layer thick one on the right is, from top to bottom, vinyl ester fiberglass -
3/4" marine plywood - VE fiberglass - end grain balsa - VE fiberglass.
You won't find a C-Dory transom like this one and shouldn't expect to.

Aye.
 
Nick,

I read your original starting post. Interesting topic for a power choice on a 22 Cruiser. A C-Dory 22 Cruiser is a great boat. We have a C-Dory 23 Venture and it is powered with a Suzuki df140a outboard. I never motor for prolonged periods of time at full throttle and if I do it is no more than for 20 seconds. Our boat is rather heavy as used. We have a 19" 3 blade prop currently. The Suzuki 140 is a 2044 cc 4 cyl. motor. I feel that it compares to a Suzuki 115 HP motor but is lighter because of design changes. When I hit the 6K rpms mark and do so ever so rarely, it comes alive and I have hit 34 Knots (39 mph) at best sea conditions. This speed is too fast for any C-Dory (basically flat transom reasons). The boat handles well at this speed but it is way too fast for my comfort. Definately, don't go with a Suzuki 140 HP motor on your 22 Cruiser. It would be a mistake in my opinion. Is there a reason for you to have this amount of power on a 22 Crusier? Wish you the best in your research.
 
39 mph is flying along way too fast! But, if somebody was looking for a 30 mph cruise or so, that would put the 140 at less than 80% work capacity as the 22 would theoretically go a tiny bit faster before it burns up in the atmosphere after it launches into outerspace. Kidding aside, I suspect the 115 Suzuki would be only be a hair slower in real usage since they are very similar in so many ways. If you can stay down below 80% power output, your engines will last and last. How do I know??? Well it's a very rare day I push mine past 5k RPMs and they have nearly 3k hours on them and are still going strong. A Volvo marine mechanic once told me that 80% of the wear an engine has is during the last 20% of the throttle. Beats me if true, but I have lived by it for multiple boats and for many different engines.

Repowering is a serious deal and how someone uses their boat should absolutely factor into the power equation. I feel twin 45s or a single 90 is enough for fishing trip, but wish they comfortably went a bit faster when the seas are flat as they are screaming at 30mph - a speed where the boat is fine. How much does this shorten outboard life? I don't know, but some for sure. If you just went by sound, you'd swear you're going 100 mph!

When fully loaded for a camping trip, 90 hp barely cuts the mustard and turning a 3 hour boat ride into a 5-6 hour boat ride because you can only travel 18 mph at 100% throttle is just rediculous and hard on engines. On the other hand, 90 hp is more than you will ever need on a Seward trip, because the seas are going to suck and you can just about count on lots of 10-20 mph usage. And, that's if you're lucky!

Anyway, I'd choose the engine that makes you happy with your boat for what you are using it for. Someday I'm going to repower mine, and that is a big decision and I'd rather shoot over than under.
 
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