How to make boat faster?

[Majestic]

My boat seems beyond slow, it's kind of expected because the motor is a 30HP Honda 4 stroke and the boat is a 16 and a half foot Lund Rebel SS. It seems like it should be faster then what it is though.

I'm guessing I only can go about 10-12 MPH when I'm WOT. It doesn't seem like my boat and motor are in unison. I play around with the tilt but it doesn't seem to change much.

I researched this one late night awhile back and found a thread where some guy had a 4 stroke that was really slow on his boat and he added something to his boat and said it was like adding an extra 10HP, it was much faster.

Problem is I can't find that thread or remember what they were talking about lol.

Any suggestions? Thanks

[team wild]

Could it they were talking about A hydrofoil? Do you A power tilt and trim if you do start the motor in the down position and when you get on plane slowly start triming the motor up till you hit the sweet spot and that should be your top speed for the set up you have the hydrofoil should help the boat get on plane faster.

[TruthWalleyes]

I have a 16' alumacraft loaded to the brim. Probably at weight capacity with just me in it. 25hp OLD evinrude. I can go 24mph.

It should go faster than what it is. Hows the prop look? Motor sound like it is getting up to proper RPM's?

[wayne123]

make sure the bottom of the boat is nice and clean. I know with fiberglass boats you wax the bottom and they go faster. I am not sure if you do that with an aluminum boat.

[GooBack]

Waxing a fiberglass hull is the last thing you should do if looking for better performance. Slick surfaces are stickier in the water.

It will not work on an aluminum boat either.

[1968]

Both my ancient larson and my 16 foot jon boat picked up 5mph from thorough cleaning and waxing. Had used both for years before trying, so I know the gain was real.

[GooBack]

I'm sure...

Wax away! Wax twice...gain twice as much!!

[kg2]

Cleaning may be one thing, but waxing is another. GooBack is correct. It is all in the physics.

[Xplorer]

There is something just not right.

I had the same 30HP Honda (tiller) on the back of a 1997 Lund Explorer 1600(615#, max load of 1120#) and with a medium load and me I could get 26 on gps.

I would look at the prop size to start, and go from there.

[RebelSS]

Something is wrong. I have a '97 Rebelss console with a 30 HP Johnson 2 stroke...and I run WOT @ 27 MPH per GPS....always have. What the heck prop have you got???

[highlife4me]

Do you have too much weight in the back of the boat? I have a 14' Lund with a 25 horse Yamaha and it can take forever to get on plane with me in it alone. If I put a pail of water in the bow it takes right off. Try moving some weight around and see if that helps.

[1968]

I'm going to have to disagree a bit. I can't argue physics. I can argue real world results. The Larson had been cleaned thoroughly before and only broke 27 on it's best day. After getting the deluxe treatment, and nothing else, it gained exactly 5mph. Just like the 2 people that told skeptical me about it many years ago. The jon boat got a slop job and guess what, 5mph. Both boats verified with my Eagle's paddlewheel speed sensor and a GPS12.

So as I see it, with or without physics this advice may help the OP go faster. If that's the end result of waxing, that's pretty cheap enhancement. He may not see five as all the reports I know of were on boats that could already do at least 25mph. Every bit helps though. And it can't be all this, there has got to be something else holding it back too.

Plus polishing/waxing will help all that incriminating water from sticking to the boat on the way out!

[Esox_Magnum]

Air between the hull and water make speed, waxing reduces the air pockets thus resulting in lower speed...Would bet the extra cleaning the 2nd time around had as much to do with the gain than the wax....

[Majestic]

The hydrofoil was actually brought to my attention from a buddy last night shortly after I started this thread. I'll be getting one of those forsure.

They were talking about doing something in front of the boat though like adding something to the boat.

I do not have power tilt, I have to do it manually with a little bar it has 5 holes, I've tried every hole.

The prop is brand spanking new, it's a Honda prop that is the same that originally came with the motor.

The motor sounds great, sounds like it's full power it just doesn't push the boat like it should.

I'm just guessing how fast I go right now but I doubt I'm far off, I was with my buddy the other day who has a similar boat except his is a 40hp 2 stroke and his boat goes 29mph. I'd be lucky if I go half that.

I'm hooking up a new fish finder this week with GPS so when I go test that out I'll know how fast I go forsure.

[Esox_Magnum]

Prop may be to small

[CAMAN]

Did you detach the boat from the trailer? I've heard that can slow a boat down quite a bit.

Can you take a picture of the back of the boat and tell us the prop pitch? I'm guessing either the prop is pitched way to high, the motor shaft is too long for the transom, or the boat is overloaded somehow.

[Moose-Hunter]

Hold the phone! Put your wallet down and set away from the check out counter!!

Before you go throwing money at this issue... Create a workable baseline. Examine what you DO have before going any further. Does the prop your running have the correct diameter and pitch? Verify and re-verify. Is the engine mounted at the proper height on the transom? Not trim, but height? I had a Yamaha years ago that needed a spacer added on top of the transom to get the cav plate at the proper height. How is the weight distributed in the boat? Gear, gas, people... Are you overloaded?

There are so many different things to check BEFORE spending money. From what I've seen, your boat should be in the 25+ mph range. 30 should be very possible. The fact your not even close, tells me basic set up is WAY off. If so... Adding parts (hydrofoil...yuk! A band-aid for bad set up.) ain't gonna do a thing for you.

I'm no expert, but I have set up a boat or two.

[harvey lee]

I agree something has to be set up incorrectly or a wrong pitched prop.

Also help with a gps for speed or a boat along side with a gps to see how fast you really are going.

very hard to tell by just looking, harder than one realizes.

[CaptainMusky]

Hydrofoils are a gimic. Save your money. Don't buy a thing until you know exactly how fast you are going and that its properly prepped including mounting location like others have said. You will save yourself time and money in the end. Check your transducer too and make sure its nit mounted too low causing drag.

[aanderud]

Hydrofoils are a gimic.

While I agree that a hydrofoil is NOT going to solve this guy's issues, your statement that hydrofoils are a gimic is completely false. They do help a rear-loaded boat (e.g. tiller motor and only one person in the boat) get on plane faster and stay on plane at slower speeds, and that can be valuable in some situations.

[hydro]

I would guess that the OP’s boat should do in the mid 20’s range at least, so something is definitely wrong as stated above. Some things that could be noted for the baseline would be, again, the pitch and diameter of the prop, description of “hole shot” or at least where the bow goes with respect to height as speed is increased (does it stay up in the air?), position of the cavitation plate with respect to the bottom of the hull (motor height), and lastly, what is in the boat and where is it? (weight and distribution). The answer to the problem will be in one or a combination of those variables.

As to the comments on waxing, at these low speeds there is absolutely no effect positive or negative on speed specific to the application of wax. Esox nailed it above as to why this works. In racing boats the bottom preparation for high speed hulls (75 mph++) includes roughening the hull finish slightly with 400 sandpaper parallel to the hull to break up the surface and free up the water molecules. Waxing will slow down the hull in that situation. At 20 mph all you get from wax is a pretty boat and a tired arm.

[DTro]

Yes, there are some setups that a hydrofoil will help out and it helps my boat quite a bit to stay on plane at a slower speed. I can tell you this though you sure won’t gain any speed with it and most likely will lose about 5% speed. I really like having a hydrofoil on my boat though and would recommend them for sure.

The very first thing I would check is that the anti cavitation plate (the fins on the lower unit above the prop) are level with the bottom of the boat when the motor is in the down position. This is critical. I’ve seen where a long shaft motor was on a short transom and vice versa.

After you verify that, make sure that when you are on plane at wide open throttle that your trim is set up so that your steering doesn’t pull at all and you don’t want the bow pushing down into the water at all. If it is you are trimmed down too far. There is a sweet spot that will gain you a few mph. Without power trim though you will have to compromise between your hole shot and plane speed, you can’t have the best of both without power trim.

The next thing you should look at is weight distribution. Not a huge deal but balance everything out and make sure you don’t have a bilge full of water or something weighing you down.

Then after all that you should start looking at engine performance. It’s possible you might be only running on one cylinder or you might have weak compression or maybe running rich.

Endless possibilities, but you should start eliminating the easy things first.

[PerchJrkr]

Try a bigger motor.

[Northlander]

Check your prop and make sure you didnt slip a hub. If so get a new prop. I had this happen on a 14' with a 25 horse and I couldnt get more than around 10 mph out of it alone. I will say it ran fine before the hub went of course. Did you all of a sudden start having the problem or has it always been that way?

[tonkapat]

Try a bigger motor.

your looking at low 20's as a best case scenario, If you can get it on plane. Boat is to heavy for a 30 four stroke. I have a 16 rebel 200+ pounds lighter than your boat with 25 4 stroke and its underpowered. 23-24 mph when alone. 2 guys maybe 21 3 guys maybe 17-18. Get a tach first and foremost, then tell us your gps mph and rpms and prop diameter and pitch. Without knowing that info your just wasting time.

My advice is sell the honda and get something that is at least 75% of max hp.

[CAMAN]

I believe that boat has a max HP rating of 40hp. So he is atleast 75% of max. That motor should at least get him on plane and decent performance if everything is set right.