Too much motor for this tunnel hull???

[frozenokie]

Preparing to purchase a 1973 Road Marine Marathon Tunnel Hull boat with a 1990 Yamaha 250HP outboard. My fear is the obvious! I think the motor is too big for this 17' tunnel. I am open to opinions about this subject simply because I've owned several types of boats and PWCs, but not a tunnel hull - let alone with a monster 250HP motor. I've had up to 175HP motors, but they were mounted on heavy V-bottom fish-n-ski hulls. My guess on the largest outboard (which still may be crossing the boundary) is a 150HP.

Also, can anyone direct me to a place to get more information on the hull itself. Since Road Marine is no longer in production, I'm having difficulty getting specifics on the hull characteristics and the maximum capacities.

If the opinions received lean towards "go with it", then I'll keep the outboard. But if the opinions are otherwise, I'll be looking for someone to trade with. I have checked out the engine, lower unit, trim unit, etc. and all is in remarkable shape.

Thanks for any and all help

 

[5150abf]

Re: Too much motor for this tunnel hull???

Ya, I would say that is massivly overpowered, the biggest engine you could get back in 73 was a 150 maybe.

That has to be one scary fast ride, it may be modifies to take that kind of power but a 250 on a 17 sound slike a horrible accident waiting to happen.

 

[NHGuy]

Re: Too much motor for this tunnel hull???

I think it sounds like too much motor. But try it out. If you like it buy it.
If it IS too much you could possibly trade off to a 200 or 175 and still have a 70-80 mph ride. Someone with a heavier boat with maybe a newer motor would be a nice match. And if you swap with the same brand you might not have to re-rig wiring & controls.
You could also just control yourself with the throttle.
That setup is for flatter water and bursts of very high speed. Tunnel hull owners can tell you more. Maybe you ought to go throw out your question on "offshore only" and "scream & fly". Those are high performance forums. I bet there are folks on scream & fly who could tell you a lot.
There may be some who can advise you on whether to go above certain speeds. There is a trapped air effect, too much speed could result in the bow lifting off and possibly causing a back flip.
I like to go kind of fast, to me that boat says "go riding in the early morning when the water is flat".

 

[halfmoa]

Re: Too much motor for this tunnel hull???

Just because the boat has massive power doesn't mean you've gotta run WOT....


but I'm sure I would

 

[Thalasso]

Re: Too much motor for this tunnel hull???

What is on the plate of boat as to max horsepower.(USCG). If you have an accident with injuries,it will be dooms day for you.

 

[frozenokie]

Re: Too much motor for this tunnel hull???

Yeah, my gut told me that I was probably right about the overpower. I actually wouldn't mind putting on the 'ol "tower-o-power" Mercury Thunderbolt 150HP to get'er back to an original set-up, but I would have a tough time getting some of the parts for the motor itself if things crapped out on me.

Yep, I'm a "full throttle" kind of guy myself I know I would be pushing it each outing, so I figured I shold start looking for someone to trade with.

I have been trying to find the USCG regulations on that hull, but I have been unsuccessful in my search. An I will go to the high performance forums to ask those guys too. In the meantime, does anybody know the best place to look up old boat information or ones that aren't manufactured anymore?

Thanks for all your remarks - sure helps me remember that I am human and not immortal!

 

[oops!]

Re: Too much motor for this tunnel hull???

USCG regs

http://forums.iboats.com/showthread.php?t=191283

 

[frozenokie]

Re: Too much motor for this tunnel hull???

Hats off to ya oops! i appreciate it greatly

 

[Faztbullet]

Re: Too much motor for this tunnel hull???

I would buy it and try it, if it scares ya sell the 250hp and get a 150 hp 60? Johnson. I had and raced a 16ft Texas tunnel with a 505ci BBC and a 18ft Mantra with a 468ci BBC with NOS both tunnels and you might say "overated"....

 

[Solittle]

Re: Too much motor for this tunnel hull???

Keep in mind that lawyers love guys who overpower their boats.

 

[cobra1476]

Re: Too much motor for this tunnel hull???

tunnel hull and 250hp.......... screamandfly.com

Those are the only boats on there.

 

[Chinewalker]

Re: Too much motor for this tunnel hull???

A lot of those tunnels built back then simply won't handle more power. The designers built them to handle the largest motors available, and those motors put them on the ragged edge. Extra power & weight change that design quotient. "Trying it out" may be a one time thing - literally. One bump too much on the power trim and over you go. End of story. Tunnels are built to pack air under them for lift. Too much power, beyond what the designers intended, can create too much lift. Unless you have a lot of seat time and know that this 40-year old hull is structurally PERFECT, I would not even try this beast. Start with the original style & size motors. If after a season or three you feel that you AND the boat can handle more, then try it out. Lifejacket, helmet, kill switch and foot throttle are mandatory...

 

[Chinewalker]

Re: Too much motor for this tunnel hull???

I believe it - I have driven some pretty fast ones, faster than most I'm sure. But, you don't put a newbie behind the wheel of your 500HP car and expect him to hammer down and handle it like a pro. Seat time is key. The boat may have been running with that engine for some time, but the new owner hasn't. Not advising him he can't, just telling him to learn the boat first...

 

[NSBCraig]

Re: Too much motor for this tunnel hull???

USCG regs

http://forums.iboats.com/showthread.php?t=191283

Sorry but that's useless info for the boat in question.

 

[Chinewalker]

Re: Too much motor for this tunnel hull???

As others have pointed out, the throttle has a lot of positions besides WOT.

Exactly! However, the new owner also mentioned that he was a "full throttle" guy....

 

[sschefer]

Re: Too much motor for this tunnel hull???

Full throttle guy or not, if you don't have someone to teach you how to drive a boat like that then you're in for a few scary rides while you learn. Doable though.. I'd love to take it out on a early morning run with just a little ripple on the water. Oh, by the way, flying the hull is not something you want to try right off the bat and power transom stands will likely end up with a less than desirable amount of water in the boat until you know how it comes over the bow wake. You need to know just exactly when to stab that throttle the second time or she'll be headed for the bottom.

Oh yeah, I would have fun with that boat....

SMACK.... wake up Steve, your dreaming again....

 

[Bamaman1]

Re: Too much motor for this tunnel hull???

My best friend had a Flying Dutchman tunnel hull in 1970, with a stack 6 125 hp Merc. It was good for 65 mph, but would hit 70 mph when you hit the white caps. It would corner like it was on rails--strong lateral g forces. It was a 850 pound pleasure boat, and an absolute ball. This same boat with a hot high hp outboard and good setup would probably be running in the 90's.

He later had a Molinari with a 150 hp motor that would try to take off like an airplane. Have you ever seen a tunnel flip? It's not a pretty sight to see the boat upside down with the rear end landing first.

I have never heard of this brand of tunnel hull boat. Do you have any pictures?

Have you seen the tunnel hull movies they have on UTube under "STV River Rocket" running 110 mph? They have a bunch of tunnels on different sites.

I know where there's a 1972 model Flying Dutchman hull that could be bought for $1000. It'd be great with a 150 hp Optimax--probably running 75-80 mph. That's fast enough to be relatively safe riding.

Depending on the price, it could be a good project. Like it was said, you could always sell the 250 hp motor and put something on it that would be better sized. But, the boat better be top quality, or it's an accident waiting to happen. Take a test drive.

 

[halfmoa]

Re: Too much motor for this tunnel hull???

All I am saying is that in my entire life I have never not bought something because it had too mush HP. In my book such a machine has never existed and there is no such thing as too much power.

Not to worry, my wife doesn't "get it" either and that's ok.

This post speaks to my soul...

 

[frozenokie]

Re: Too much motor for this tunnel hull???

I agree with each post. As I expected, it's good to know that I am thinking along the same lines as all opinions portray. I am a cautious person, it's just that little "wanna go faster" attitude that I always encounter when on the water - simply because I've always owned slower pleasure and bass boats. Now it's time to have a little fun I do take safety seriously and this will be my seventh boat. I have taken a look at it once already. The owner wasn't able to be there but he insisted on going to his home anyway just to peek at it. The hull is in remarkable shape. It is clear that at least one other outboard had been used on it. The transom looked and felt solid, the entire bottom, sides, and cap were exceptional. Just the little scars where the previous outboard had been, but couldn't tell when that was. As old as it is, care was part of the routine on the hull - it's the infrastructure, transom, floatation, and seams that I will be paying very close attention to.

I plan to actually meet with the owner on Sunday and ask all the important Qs. Rain expected, so won't test drive yet, but plan to do so before purchase.

I have been in fast bass boats - to a point when the nose starts gyrating and getting loose. A little is not so bad, but when it gets worse and worse... that's an uncomfortable feeling!

I will only be on this earth once and I'll be damned if I don't get a fast boat that I can "play" with and have some pride in. I love older boats probably because I like to "tinker" and makes "ugly" things more appealing. It's in my nature - unfortunately I always choose boats to poor the $$ into and not get that back in return when sold. BUT I LOVE IT ANYWAY!

As far as photos, I have only found one from when they were being produced at this link: http://books.google.com/books?id=sc...v=onepage&q=1973 Road Marine Marathon&f=false

Here are the photos from the ad:

Will let you all know more after I visit a second time. I also will be taking some photos while I'm there just to help me remember the details. I'll post them too.

Who am I kidding here fellas - HELL YEAH I'm getting a little excited