Tunnel Hulll ?

[Lil' Blue Rude]

I was thinking for some reason that the tunel ran the lenght of the boat. It doesn't look like the G3 pictured has it's motor raised any higher then the motor on my boat. Could be how the picture is. How much higher is that motor raised?

 

[S&MFISH]

Hey Rude,on my Alumacraft with a 2'' tunnel,the shoe sits 2'' higher than it would without a tunnel.It would still get wacked if I ran over a rock.Because it has before,on the Big. The tunnel starts about 3-4ft from the transom. I believe it would take a 4-6'' tunnel to protect your shoe.

 

[reedjj]

S&MFish,

Do you have the 1546 DDT?

 

[S&MFISH]

No reed. It's an '06 MV1756RR with a 115/80 Merc jet.

 

[reedjj]

No reed. It's an '06 MV1756RR with a 115/80 Merc jet.

Is there a thread with pics? Sounds nice!

 

[S&MFISH]

Here you go reed.These are from '08-09. Scroll down about halfway down the page.
The first 2 are at Lake of the Ozarks and the last 2 are from CouncilBluff.
We bought it new in spring of '07.I'm going to get some recent pics after I do a good cleaning when the weather clears up around here.I'm about halfway thru it now,just needs the wash job.

https://www.tinboats.net/forum/viewtopic.php?f=48&t=7593

 

[reedjj]

Im so jealous of the jet motors.

 

[sparkbr]

A boat with a tunnel will sit lower in the water, but it is minimal. In order for something to float, it must displace it's weight in water. Assume something around a 16' boat weighing 1000 lb loaded evenly (for simplicity) and lets say it's footprint in the water is 13' x 4'. So 1000 lbs divided by 8.34lbs per gallon of water is 119.9 gallons it must displace to float. 119.9 times 231 cubic inches per gallon is 27696.9 cubic inches... 27696.9 divided by 7488 (the foot print of the boat) equals 3.69" submersed.

For a 2" tunnel 4 feet long and 10" wide, that reduces 480 square inches, or 2.07 gallons. The same as adding 17.32 lbs in the rear of your boat. If we were to refigure the above for a boat weighing 1017.32, it comes out to 3.76" submersed. So that 2" tunnel makes the boat a 1000 lb boat sit .07" lower in the water, or a little over 1/16"

Now, lets say we go extreme and take the area of the tunnel completely out of the picture (which could not happen unless the tunnel had no 'ceiling' to it) say the tunnel is 10" wide by 4 feet long again - Now the foot print of the boat becomes 7008" instead of 7488. The boat would now be submersed 3.95"


Now granted all of this is assuming the boat is loaded evenly in the water, so all of the numbers here are just for comparison, but all in all, the tunnel has a minimal effect on how low the boat sits in the water

 

[Lil' Blue Rude]

This post has gotten way to in depth. :lol: When I said sets lower in the water I meant rides lower in the water. peolpe with the tunnel hulls are claming they can run shallower water then they could if they had a flat bottoms. I think the oppisite is true. Your jet might run shallower put your boat won't. Here's a pic of a 17' 52" blazer sport with 4 people in the back half of the boat and it isn't running as deep in the water as the G3 posted earlier.

 

[reedjj]

I was just looking on the Sea Ark Website at tunel hulls and Jet tunnel hulls. There is a difference between the two different types of Tunnel huls in thier boats.

The Prop tunnel hull is described as....

Copied from Sea Ark Website: https://www.seaarkboats.com/boat.php?measure=Standard&boat=1652MVT

"SeaArk’s Tunnel Hulls are designed to be used with a conventional prop driven engine. The transom is higher than on a conventional hull and a “tunnel” is designed into the bottom of the boat which allows the engine to be raised so the prop turns inside the “tunnel.” Tunnel Hulls are most often used when the operator needs to run in very shallow water but does not want to lose the “bite” of the prop. Standard features and options are similar to Non-Tunnel Hull models".

And the Jet Tunnel hull is described as:

Copied from Sea Ark Website: https://www.seaarkboats.com/boat.php?measure=Standard&boat=1652MVJT

"SeaArk’s Jet Tunnel Hulls are designed to be used with a jet driven outboard. The Jet Tunnel design includes a flat roof in the tunnel to direct water back to the intake of the jet. The thrust of a jet outboard is about 70% of an equal sized engine with a prop. This fact and the fact that a jet uses water for propulsion instead of a metal prop, means that the operator loses some speed, directional control, and performance. What is gained with a jet is the ability to operate in extreme shallow water conditions without the fear of ruining a prop. Most of our customers using Jet Tunnel boats use them in shallow rivers where they need to pass through extreme shallow spots. Standard features and options are similar to Non-Jet Tunnel Hull models, however, they are offered in center console only".

I would only guess that a jet outboard would not work AS WELL on a tunnel hull meant for a prop, and the other way around due to the specific designs.

When I was looking at buying the G3 I noticed that the Jet Tunnel was very shallow, just enough to give the shoe some clearance (you can see this in the pic above). And the Prop tunnel was much more pronounced to make room for almost the entire prop. Only the skeg was below the hull of the boat.

I think the engineering, design, and science behind boat hulls, even something as simple as a "Tin-Boat" is very interesting. I am really enjoying this thread. Especially learning about the different pts of view, applications, hull designs and materials used on everyones boats from all over the country (and Canada). The guys in MO are running different setups than the guys in Ak, and the guys in PA are running heavy duty with UHMW. Some are running jets in FL and yet others swear up and down that its a bad idea. Inboard Jets running class 5 rapids in Idaho, and guys in Alabama running jets on riveted jon boats.

I am learning a lot from everyone on here and will put it to good use on my next boat.

 

[optaylor823]

LiL Blue Rude peaople maybe claiming they can run shallower, but we all know the only true way to find out is if we take a boat with out a tunnel and add one. Maybe this is a case for Mythbusters.
Reedjj. A tunnel hull for a prop does not work good for a jet outboard. They are to big. Also if any one is interested here is some good reading on jet tunnels, and other information about setting up a jet boat.

 

[fender66]

LiL Blue Rude peaople maybe claiming they can run shallower, but we all know the only true way to find out is if we take a boat with out a tunnel and add one. Maybe this is a case for Mythbusters.
Reedjj. A tunnel hull for a prop does not work good for a jet outboard. They are to big. Also if any one is interested here is some good reading on jet tunnels, and other information about setting up a jet boat.

Um....optaylor.....think you forgot to add a link to that reading you mentioned.

 

[Lil' Blue Rude]

Lets see a tunnel do this :mrgreen: . https://www.youtube.com/watch?v=V9iXL-omjkA&feature=related

 

[optaylor823]

Yes I did sorry about that. https://www.snyderboats.com/faq.htm

 

[RPjet]

Lil Blue,

Believe it or not but a tunneled jet will go the same place that the boat you posted the video for with one exception. If you watch closely the motor actually hit and kicked up upon contact with the bottom. A tunneled hull boat may or may not hit under the same circumstances but I believe that the motor would not have made contact as much.

You seem to be misinformed or under the wrong impression about tunneled hulls. They will run as shallow as a non-tunneled hull. Most east coast tunnels are only about two inches high, about one foot wide and two feet long. They do not stretch the length of the boat.

And another thing - east coast boats are made much heavier and thicker than those you keep posting pictures of. A hull of less than .125 will not survive very long on the east coast rivers. Sure lighter boats will run shallow but will not take a hit and survive like those that we run in our rivers.

BTW.......I run a boat from Missouri......a RiverPro LoPro! So someone out there knows what it takes to run the east coast rivers (Thank you Kevin Turner!).

 

[Lil' Blue Rude]

I meant that as more of a joke, like look how shallow this thing runs. :shock: I know the motor hit. But still pretty cool that he ran that shallow.
Like I said in an earlier post I see how your tunnels work. I was thinking of the tunnels like the ones on a small hydro plane where the tunnel runs the length of the boat.

 

[Scottinva]

It really all just comes down to what you want and where you run it. None of our jets could handle the big waters in the Northwest. They have totally different waters. Our boats on the East coast are made for the Susquehanna, James, and New Rivers. No offense inteded, but one of those thin hulled boats would not last very long on the Susky at summer lows running as fast as those boats run. That is why our boats are built the way they are. They still run real shallow and can take a beating. If you look at the Snyder website, you will see how heavy duty they are made. They may not run as shallow as a Blazer Sport, but it is not because of the tunnel, it is because they probably weigh 2x as much or more. However, if we hit a ledge running 30 mph, we will live to see another day with maybe a small dent in the UHMW. A thinner hull with no UHMW will not be so lucky. Just different boats for different waters. You don't need those heavy duty boats like we need. Ours may be slightly overkill, but I like the insurance.

Scott

 

[Lil' Blue Rude]

I know your guys boats are alot tougher then what we run. I'm glad we don't need boats to be that heavy duty around here. Kinda cool to get all of the diffrent points of veiws from diffrent people on diffrent boats.

 

[sparkbr]

Here is a pic of the tunnel I welded into my 1652 roughneck. I run a 60hp prop driven mariner on a hydraulic jackplate and can run on plane in about 3-4" of water and at low speeds in about 5-6" depending on how loaded I am. There is alot of mud bottomed water around here though so making a mistake is rarely costly.

 

[shallowminedid]

my buddy has a beaver tail that was rebuilt into a tunnel hull by snyders.. had the uhmw bottom added.. it now leaks like a civ? and is almost twice as heavy but it will drive onto land and not hurt anything he can park it up out of the water on the shapest nastiest rocks and not worry about his foot.. if u get the tunnel add the splash sheilds and cav plate if needed and u should be fine.. my boat is not a tunnel and i can not get to some of the places he can