Tunnel Hull Boats

[ShawnQ]

Ok guys, just bought my first tunnel hull.<br /><br />I took it to a local lake yesterday, and was impressed with the performance of it considering it is, what most people would say, 'underpowered'.<br /><br />I was running 32-35mph on fairly calm water (slight chop) in a Blue Wave 189T w/88 Evinrude SPL.<br /><br />Anything special I need to do pertaining to tilt/trim considering it's a tunnel hull? For instance, is it better to keep it trimmed all the way down while on plane so the engine/prop is seeing more water?<br /><br />Thanks!<br />Shawn

 

[LubeDude]

Re: Tunnel Hull Boats

Now the fun begins, I love performance questions!<br /><br />I think depending on the length and weight of this boat you should be able to get close to 50MPH out of it!<br /><br />Please post the RPMs you were turning at WOT, and the current pitch and # of blades on your prop! Aluminum or SS. We can go from there!<br /><br />You will need to trim out if you are going to get the maximum out of this boat! You should have the following in working order! Kill switch, (and wear it), Water preasure guage, water temp guage, and accurate tach! Max RPMs for this engine should be in the 5500 range!<br /><br />Now, for your safty, this is a Performance hull and requires caution! Always wear your life jacket! Tunnel hulls are tricky, use your head!

 

[ShawnQ]

Re: Tunnel Hull Boats

50mph is doubtful, I think.<br /><br />It's an 18'9" boat, not realy sure on the weight. I want to say 1100-1200, but could be wrong. You can find out at www.bluewaveboats.com , but I dont have the time while at work.<br /><br />It has a 4 blade stainless prop, will turn 5500rpm, and I was cruising at 5000-5100. <br />The only marking I saw on the prop was '13'.<br /><br />If you nail it to launch, it will toss you out of the boat if you aren't holding on. It takes off like an AWD car, very minimal slip.<br /><br />It was running 20-25psi at full throttle, and I am not sure on the water temp (no gauge), but it definitely wasn't hot. The water coming out was luke warm.<br /><br />Kill switch was in-tact.<br /><br />Let me know if this helps

 

[LubeDude]

Re: Tunnel Hull Boats

Your right, with an almost 19' boat and the 88 HP it would be a bit of a strech to reach 50! But it does seem that if it will reach 5500 without trimming and it jumps out of the hole like it does, I would think that you could at least use more prop! being underpowered as it is, trimming might not actually help a whole lot! Did you try it at all?

 

[ShawnQ]

Re: Tunnel Hull Boats

To be honest with you, I was happy with the way it was performing trimmed in...so I left it.<br /><br />The only time I trimmed it up at all was when I was drift fishing in shallow water.<br /><br />It was also night time, so I wasn't exactly trying to get the top speed out of it, I was cruising the majority of the time. I opened it up a few times just to see how many RPM's it would spin.<br /><br />I'd imagine that I could spin more then 5500 if I trim it, but I dont think a whole lot more. So, maybe a LITTLE more prop, but not much.<br /><br />How much does front/rear weight affect a tunnel boat? I would imagine if you have all of your weight in the back, you will have more of the boat in the water, meaning more water in the tunnel, and more on the prop. Would this help launch and top speed?<br /><br />I am really not looking for top speed, to be honest. I am content/happy with what it has. I just want to find out the best way to get up in shallow water, and what is easiest on the engine while on plane. But, a few mph never hurts <br /><br />Thanks!<br />Shawn<br /><br />

 

[imported_Mike_M2]

Re: Tunnel Hull Boats

I would think it should go faster. My brother has an open bow 19 with that same motor and it does 35. Your boat wieghs a lot less. A quick jump out of the water is a sure sign you need more prop. Less junp means more MPH and at lower rpms(which is good). Also, it will improve gas mileage.

 

[Hopsdak]

Re: Tunnel Hull Boats

I am really not looking for top speed, to be honest. I am content/happy with what it has. I just want to find out the best way to get up in shallow water, and what is easiest on the engine while on plane. But, a few mph never hurts

The best way to get up in shallow water is to trim the motor under all the way. More weight in the front of the boat is better. Another trick depending on your hull, is to cut a counter clockwise donut rolling the boat on it's side and catching the prop wash when it comes back around. When the boat rolls it pushes more water to the prop. Most of the time it only takes a 1/4-1/2 donut to get it on a plane. If that doesn't work look into getting a shallow water blaster or ned ski for extra lift. It will take a few off your topend but, if you have a jack plate it's a must have for a tunnel boat. It will allow you to run the motor higher up in skinny water and keep the water from the tunnel flowing to the prop.<br /><br />My Gulf coast runs about 39mph and it has a 130 that turns about 5800 rpm wot. <br /> Port side GC 180 <br /> Nedski <br />Later, Hop<br />P.S. Where do you fish out of?

 

[ShawnQ]

Re: Tunnel Hull Boats

Thanks for the tips!<br /><br />I dont have a jack plate, and really dont fish shallow enough to need one, so I probably wont get one.<br /><br />I fish in the rockport/aransas pass area.<br /><br />Thanks again<br /><br />Shawn

 

[ChrisMcLaughlin]

Re: Tunnel Hull Boats

ShawnQ,<br />I am running a Seafox 182 Bayfisher, Merc 90 Saltwater with a 3 bladed 13x17 pitch s/s prop. The weight is @ 1500 lbs. including engine. The WOT IS @ 5600 and top speed by GPS is at 36 mph. This sounds similar to yours. I think you may need a little more pitch to get your WOT up but you are close!

 

[ChrisMcLaughlin]

Re: Tunnel Hull Boats

OOPS! Less pitch.