Help me make my Glen L Stiletto Wooden boat FASTER!! (Advice needed)

[80's old school]

Hello, I have a 16 foot Glen L Stiletto Boat. It is a completely wooden home built boat. I wish I could claim that I made it... but I didn't! I have used it for a few years at 5600' elevation. At this elevation I had to detune the boat to run OK at high elevation. At this elevation, the boat would run an honest 45 MPH. Now I am operating the boat closer to 1000' elevation, I retuned to stock and the boat runs an honest 55 MPH. Now I have caught the speed bug!!The boat weighs a little over 900 pounds with motor. I have a 1997 Evinrude 115 60 degree outboard with a 19 pitch Stiletto prop.The motor is set to the lowest height setting. I just purchased a water pressure gage. Next I am going to start raising the motor.My next move will be a jackplate and then.....????
For now, here are some pictures of the boat. More questions are coming.

[80's old school]

Here is a picture the previous owner gave me. As you can see, not much bow lift. You can see he is trimmed out... would raising the engine help here? Remember, it is at the lowest setting.

[80's old school]

Pictures of the structure..

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Now here is one problem I need your opinion on. The previous owner installed a fin (skeg) in the middle of the boat to help with stability... This does help the handling, but I am focused on going faster. What is your opinion on this fin?

[80's old school]

The previous owner installed these adjustable trim tabs.. Do these help or hurt higher speed performance?




Side profile view of boat....

[David]

Raising the motor will reduce bow lift. Adding setback will help carry the bow. I wonder if the trim tabs were added to address a porpoising problem. They might be keeping the bow low. The fin will greatly improve cornering but will cost speed.
Pretty boat.

[80's old school]

I see your point.. With this boat only being 16 foot long, I don't think I need to set back the engine.

Next time I go to the lake I can remove the trim tabs and experiment. I will also raise the engine because I feel the engine sits way too low in the water.

I want to systematically try one thing and then run it with GPS to keep track of what I am doing.

Is it OK to spin this Evinrude to 6000 RPM?

[Onetime]

Always liked the Glen L boats and the Stiletto has always been one of my favorites. Looks like it was a very nice build.

Where is the fuel tank? Sometimes they were put in the bow which could make it bow heavy.
The trim tabs look like they are flush to the bottem of the boat. I was always told this was a no no as it causes more drag. Should be minimum of 1/4" above the bottom.
Your 55 mph speed is quite respectable for that package but it does look like it's running pretty wet and should have room for improvement.

I wouldn't run it without the skeg as it won't turn but skid. Have you put a straight edge on the bottom to be sure there is no hook?

[Jimboat]

I will also raise the engine because I feel the engine sits way too low in the water.

What height (above bottom surface) is the centerline of motor torpedo currently (at 55mph)?

[blacktruck]

Nice boat. Since it is a flat bottom, you will not get much bow lift and you don't want much bow lift. Raising the motor will reduce drag, increase RPM and the boat will improve top end, slightly. You should be running only a small amount of positive trim.

On a trailer, measure the prop shaft to the bottom of the boat, it's easier to measure the anti-ventilation plate but most use the prop shaft. Expect about 100 RPM per inch more as you raise it. With this set up, just do a moderate increase. You can probably squeeze a couple MPH out of it. That is a nice setup. The trim tabs are probably there, like the others mentioned for porpoising, that flat hull should plane no problem.

The mid 50's speed range is good for that hull.

[80's old school]

What height (above bottom surface) is the centerline of motor torpedo currently (at 55mph)?

Are you referring to the engine being level and then the difference between the propshaft centerline and the bottom of the boat?I don't have the boat here with me now, but just guessing / estimating the centerline of the propshaft is about 5-6 inches below the bottom of the boat with the engine being level.My boat is at our Lake house. I can go there tomorrow and check measurements. Please describe exactly what I need to measure and I will report back. Thanks!

[80's old school]

Always liked the Glen L boats and the Stiletto has always been one of my favorites. Looks like it was a very nice build.

Where is the fuel tank? Sometimes they were put in the bow which could make it bow heavy.
The trim tabs look like they are flush to the bottem of the boat. I was always told this was a no no as it causes more drag. Should be minimum of 1/4" above the bottom.
Your 55 mph speed is quite respectable for that package but it does look like it's running pretty wet and should have room for improvement.

I wouldn't run it without the skeg as it won't turn but skid. Have you put a straight edge on the bottom to be sure there is no hook?

Thank you for the compliment! The guy who built it did an outstanding job!

The fuel tank is in the center of the boat. The pictures describe it best. I think he put the tank in a reasonable location.




The trim plates are flush to possibly 1/8 inch above the bottom of the boat. I can measure tomorrow to be exact. Luckily they are easy to remove to test and easily repositioned if needed.

As for the fin / skeg, I would like to get more of the boat out of the water. If more boat is "not wet", then the fin will be less an issue. I could also "profile" the fin shorter if this would help with top end performance.

I will check tomorrow to see if there is any hook. At first glance I would say no, but a straight edge will tell the story.

Thanks for the info!!

[80's old school]

Nice boat. Since it is a flat bottom, you will not get much bow lift and you don't want much bow lift. Raising the motor will reduce drag, increase RPM and the boat will improve top end, slightly. You should be running only a small amount of positive trim.

On a trailer, measure the prop shaft to the bottom of the boat, it's easier to measure the anti-ventilation plate but most use the prop shaft. Expect about 100 RPM per inch more as you raise it. With this set up, just do a moderate increase. You can probably squeeze a couple MPH out of it. That is a nice setup. The trim tabs are probably there, like the others mentioned for porpoising, that flat hull should plane no problem.

The mid 50's speed range is good for that hull.

Thanks! I will measure as you mentioned tomorrow.

I was wanting a goal of mid 60's with a dream of close to 70... Is this impossible with this type of hull? Or just impossible with that motor?

Future Mods I was thinking about were as follows:

Jack Plate
Prop Change if needed
Trim Tab move (if needed)
Milled Head (higher compression=more power)
Boyeson Reeds

I know the fastest way to have a faster boat is to buy a faster boat.... I just like the classic looks of this boat and love the compliments every time it is on the water. I want to also impress with its performance.

Let me know if these goals are unrealistic... I could always looks for a larger engine, but it would be nice to make do with what I have.

[Karsten]

Great looking Boat.....I wish I had the skills to build something like that. That is a pretty shallow (flat bottom) and I don't see that 115 getting much faster. Without lifting strakes the hull isn't going to come out of the water like a Deep Vee. So the hull will always have a lot of water surface area contact limiting the speed.

55 MPH is very respectable for an all wooden boat with a 115 HP motor.

I have the opposite problem with a 16 ft Deep Vee (no Pad) and a 150 Optimax on the back......I am told the boat should do 80 but will chine walk at 55-60 and no way to get rid of that without the pad.

Again, awesome little boat.

Karsten

[olboatman]

Set up is the first thing I would improve for more speed as said before. I would also check to see if that is the largest hp engine built on that platform. I have seen carb and timing changes add some good hp to the proper motors. I would check this before making a prop change. Gary

[80's old school]

Great looking Boat.....I wish I had the skills to build something like that. That is a pretty shallow (flat bottom) and I don't see that 115 getting much faster. Without lifting strakes the hull isn't going to come out of the water like a Deep Vee. So the hull will always have a lot of water surface area contact limiting the speed.

55 MPH is very respectable for an all wooden boat with a 115 HP motor.

I have the opposite problem with a 16 ft Deep Vee (no Pad) and a 150 Optimax on the back......I am told the boat should do 80 but will chine walk at 55-60 and no way to get rid of that without the pad.

Again, awesome little boat.

Karsten

Well luckily I don't have any problems with Chine walk! This boat exhibits Zero chine walk all the way to 55 MPH.

The boat gets faster and faster the more you trim, but the porposing gets to be too much. I can run the speed up to 55 and it is bouncing... Trim down slightly and she runs 50 mph as smooth as glass.

Since this is a wood boat, could some form of pad be built to the bottom and faired in? I know this is not an easy proposition, but I am never one to take the easy route always!!!