Legal requirements for putting ski motor in Jon.

I'm sure it changes from state to state but is there a rough guideline on how to overpower a boat legally? I was discussing it with friends and all the naysayers of course say it can't be done legally.

Once you have done that type of conversion the original manufactures specs get thrown out the window.

Wouldn't you get a ticket from the game warden if you had a 50 hp ski motor in a 25 hp max Jon?

That's more of a coast guard thing. I'm from Texas so this is a funny question to me I've been stoped multiple times by the tw and they just ask what I got in it and when I tell them they usually say good lord and either chuckle or shake their heads ask me for life jackets and leave.

If airboats are legal in your state then a custom jet jon should be too. Airboats have zero floatations and 400-500 hp motors

Link to the USCG boat builders guide.

https://www.uscgboating.org/regulations/boatbuilders-handbook.php

There are 3 pgs on how to size an outboard for a boat, but there are no restrictions on an inboard. I checked this all out before starting my project, called the CG. They, nor the DNR, require inspection of the modified boat. It needs to be re-registered as a 'homemade' however. You cannot sell it for a period of time.

My 1648 has 50 HP max on serial plate, I had them put 80 hp on registration, they didn't have any problem with it.

Hope this info helps.

I live in SC, so, the rules of my state may be different than elsewhere, so, YMMV.

I've got a 160 HP MR-1 engine in my jet boat, which is a Duracraft 1648SV, rated for a 50HP outboard. And the insurance company never even balked at insuring it. Further, I will tell you that throughout my interactions with DNR over the years, I have never seen an officer check a rating plate as it pertains to HP. They will, however, issue a ticket for overloading with passengers.

One thing you have to remember about HP ratings on johnboats is that this is based on the engine weight and the amount of torque it applies to the transom. When you go to an inboard, all of this changes. For instance, a 50HP outboard weighs around 205 lbs. And all of that weight is on the transom, hanging off, which puts a lot of stress there, and it makes the stern ride lower.

The average jet ski motor weighs anywhere from 100-200 lbs, and because of the jet tunnel, the engine is placed about 2ft forward of the transom, bolted to the floor of the boat. So, the weight has been moved farther toward amidships, toward center of gravity, and since there is no motor hanging off the transom, those stresses are eliminated.

Also, because a jet drive is less efficient than an outboard, actual HP at the prop is not the same as an outboard. For instance, an 85HP SeaDoo 717 engine actually produces around 35HP at the prop.

CedarRiverScooter said:

Link to the USCG boat builders guide.

https://www.uscgboating.org/regulations/boatbuilders-handbook.php

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Thanks very much for the link. I will check this out and see what I'm up against. I'm in GA. I've never heard of anyone getting a ticket for this. Its funny I talked to some street cops about it and they thought it was a cool idea...

ya man I'm telling you nobody gives a dang! only comments you get will be positive.

if you live in ga. i wouldn't worry about it, i live in tn. and when i got checked on the maiden voyage 9 yrs ago. the game wardens was taking pictures with his cell phone. he did give me a fix it ticket for expired registration and let me fish rest of the day. now, they all know me on the river.
heck, we don't even need plates on the trailer
i agree with psg1 about the transom part being stronger as most of the inboard design is "boxed" in
as long as you don't live in california, you will be fine.

I don't think it's ever really illegal to overpower a boat. The only problem I think you could have is if something happened that involved liability like personal injury or property damage. If your boat is overpowered I would think it would be easier for everything to fall back on you.

BigTerp said:

I don't think it's ever really illegal to overpower a boat. The only problem I think you could have is if something happened that involved liability like personal injury or property damage. If your boat is overpowered I would think it would be easier for everything to fall back on you.

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only in coast guard regulated waters. And even still, with an "overpowered" boat, you would still need to be doing something negligent.

If memory serves me correctly, I think "Coast Guard regulated waters" is defined by any body of water connected to the ocean.

PSG-1 said:

If memory serves me correctly, I think "Coast Guard regulated waters" is defined by any body of water connected to the ocean.

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it is indeed.

redrum said:

I'm sure it changes from state to state but is there a rough guideline on how to overpower a boat legally? I was discussing it with friends and all the naysayers of course say it can't be done legally.

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The "Max HP" only applies to outboards because of the weight and torque induced stress on the transom.

BigTerp said:

I don't think it's ever really illegal to overpower a boat...

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It's definitely illegal in CT, I looked it up and posted a link on a thread somewhere addressing this very topic. It's a state-by-state thing. Granted, it probably won't matter unless something goes horribly wrong and someone gets hurt, but at that point the lawyers are up your a$$ and your insurance company has bailed on you on a technicality buried in a mountain of paperwork you didn't read closely so be wary...

ColtonS said:

The "Max HP" only applies to outboards because of the weight and torque induced stress on the transom.

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NO!!!!

The HP rating is derived by the design of the bottom of the boat (hard chine, flat etc.), the position of the driver's weight in the boat (counsel steering vs. tiller), the length of the boat, the width of the transom and the height of the transom. The transom could be made of balsa wood and it wouldn't change the rating one bit. It is trying to address how much control over the boat you have at a given speed, so as far as any legalities are concerned the max HP is the max HP no matter what engine configuration you employ.

redrum said:

I'm sure it changes from state to state but is there a rough guideline on how to overpower a boat legally? I was discussing it with friends and all the naysayers of course say it can't be done legally.

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What's the first rule of fight club?

Read the CG boat builders guide and understand what they are talking about. Performance and control testing is way more important than any sticker. You can even buy the rating stickers now with your choice of data. DNR police have been more than interested in my boat but never asked about the data plate as it is negated by the motor location and steering position.

Going from tiller steering to console steering changes the rating. A large part of the restriction is the weight of motor / operator at the transom assisting the sinking effect from doing a throttle chop at speed causing water to wash over the transom.

Honestly, 4 stroke engines should be more HP restricted vs. 2 strokes due to the weight difference.

onthewater102 said:

BigTerp said:

I don't think it's ever really illegal to overpower a boat...

Click to expand...

It's definitely illegal in CT, I looked it up and posted a link on a thread somewhere addressing this very topic. It's a state-by-state thing. Granted, it probably won't matter unless something goes horribly wrong and someone gets hurt, but at that point the lawyers are up your a$$ and your insurance company has bailed on you on a technicality buried in a mountain of paperwork you didn't read closely so be wary...

ColtonS said:

The "Max HP" only applies to outboards because of the weight and torque induced stress on the transom.

Click to expand...

NO!!!!

The HP rating is derived by the design of the bottom of the boat (hard chine, flat etc.), the position of the driver's weight in the boat (counsel steering vs. tiller), the length of the boat, the width of the transom and the height of the transom. The transom could be made of balsa wood and it wouldn't change the rating one bit. It is trying to address how much control over the boat you have at a given speed, so as far as any legalities are concerned the max HP is the max HP no matter what engine configuration you employ.

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Have you ever seen an inboard with a "Max HP Rating"??? Highly doubtful

My statement came straight from a reputable river jet builder/dealer. Since we are talking about small aluminum boats you can throw out most of the determining factors. Weight of the motor (which is located at the transom) in comparison to the strength and length of the boat has always been the #1 focus anytime a boat is being built or re-powered.

As I said in my previous posting, if overpowering with an inboard jet were an issue, my insurance company would not have covered my 160HP engine in a boat rated for a 50HP outboard. Now, if I tried to put a 150 outboard on there, they might have thought differently, as a 150 outboard weighs about 400 lbs (Merc Optimax) as opposed to the 200 lbs of a 50 HP outboard.

redrum said:

I'm sure it changes from state to state but is there a rough guideline on how to overpower a boat legally? I was discussing it with friends and all the naysayers of course say it can't be done legally.

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Short answer, no - it's a legal issue that can vary greatly state to state.


COLTONS: His question is about legality - not anecdotal accounts from someone who hasn't even read the boat builder's manual let alone done any legal research.

Until he re-registers it as a home-made inboard and goes through whatever bureaucratic process that requires (assuming his state allows it) he is probably in a legal limbo as far as what he's got and how it's regulated (at least he would be if he were in CT, and I wouldn't expect other state's laws to be terribly different. NY & MA & RI are all very closely worded to ours.) You can bet that if something goes wrong he's going to have an uphill legal battle to defend himself.

My initial comment isn't necessarily true in the jurisdiction where he's looking to register the boat as I presented it. Inboards are not subject to HP restrictions, but that has nothing to do with outboard rating relating to the weight of the motor or the strength of the transom - you're completely wrong on both accounts. Inboards have an entirely separate set of building guidelines and certification requirements, they have more stringent flotation requirements and other standards they have to meet, including different weight capacity ratings, but none of this matters from a legal perspective...his boat is not titled/registered/certified as an inboard - it is an outboard. At least in CT, your engine size (regardless of inboard/outboard type) is bound by the USCG label on the boat and you are not allowed to remove the label so no, you can't put a motor on larger than the capacity regardless of the type:

https://www.cga.ct.gov/current/pub/chap_268.htm#sec_15-140m
"Sec. 15-140m. Reckless operation of a vessel in the second degree. (a) A person commits the offense of reckless operation of a vessel in the second degree when he (1) operates a vessel at such speed or maneuvers a vessel in such a manner as to endanger the life, limb or property of another person, (2) operates or, as owner, permits the operation of a vessel loaded with passengers or cargo beyond its safe carrying capacity, having regard for weather and other operating conditions, (3) operates or, as owner, permits the operation of a vessel loaded or powered in excess of the maximum capacity information stated on the United States Coast Guard capacity information label or the capacity information label of the manufacturer affixed to such vessel, or (4) operates or, as owner, permits the operation of a vessel the capacity information label of which has been altered, defaced or removed.

See that - no mention of distinguishing between an inboard or an outboard. That is what matters for the legality of the setup - the law as it is written in the state where it applies. Good luck finding a court case that will dissect this issue further, without a subscription to a legal search engine service at your disposal it'll be next to impossible. Of course that isn't worth the effort here because it wouldn't apply unless he's in CT. But he should really look up and read the boating laws in his state (as they are recorded on the books & not relying on someone else's interpretation) unless he's going to hire a lawyer to answer his question because any ambiguity in the language could work against him, as it most certainly would if he were a resident of this freedom-forsaken nanny-state.




As far as your insurance PSG-1, did you register the boat as home-made? If you did I'd be much more comfortable agreeing with your conclusion that you're ok based on their underwriting, or perhaps you don't live in the Socialist Republic of Connectistan where his majesty the dingbat Dannel Malloy tries to interfere and direct your every move, and your state has provisions for you to follow to make these changes... Otherwise beware, all the insurance company really cares about up front is signing you up with a policy and collecting your money. Somewhere in their litany of policies and paperwork will be provisions to protect them, either a disclaimer regarding modifications or some sort of assertive statement on your part that you agree to abide by the laws regs etc. that apply to the usage of the boat in your state.

In the event of a major claim their bloodsuckers (lawyers) will find that you heavily modified the boat and at best (unless you actually read through all that legal CYA paperwork they threw your way when you signed up) you'll be without coverage until you fight it out in court with them, more likely you'll be denied.

onthewater102 : Its not anecdotal when the FACT is the USCG recommended HP rating is only associated with outboard motors. Yes every state has its own laws but if PSG-1 were to be inspected by the USCG he would not be cited because his motor exceeds the warning label, but only if the boarding officer deemed his boat overpowered/unsafe (which it is not).

I have yet to find a federal law prohibiting the act of installing an inboard motor (that exceeds the warning label) into a boat that was originally made for an outboard..... because the warning label will be void and no longer apply. But everybody needs to check their local laws first!!