boat front end drags in water...what will help performance??

I have an old 13.5 foot Performer Fiberglass semi-vee low profile boat with a 15" transom (new transom recently installed) powered by an Evinrude 40HP short shaft conversion (long shaft did not plane well). the boat moves OK, somewhere around 25-30MPH but I think it could perform better. At full throttle, the front end of the boat kicks up large wake on both sides while moving. the front seems lke it cuts and drags thru the water rather than riding above the water. I have been living with this, however in choppy water or windy conditions, this wake spray up front sometimes will get us faily wet, OK in summer, but sux when its cold outside, and can be a bit annoying at times. we dont always get wet, but the water walls are always present on both sides, rising above the boat. the boat does get up on plane, does not porpoise and obviously never has any bow rise. the bow rides straight thru the water. I dont have a power trim to try to change the angle of the ride and was wondering if a good Hydrofoil wing would help this. I understand these hydrofoils help planing without having to transfer weight foward on the boat, and will prevent bow rise. my issue is the opposite. the front of the boat rides straight thru the water, so basically you can look at it as not having enough front plane. The boat overall doesnt weigh alot, however i have added extra weight in the back with a wood constructed rear deck/seat (like a bass boat) with a 6 gallon fuel tank and one marine starting battery underneath the deck accessed thru a flip up lid. construction of this consists of 2x4 framing with 5/8" wood base with carpet. I would guess rear deck weighs around 30-40lbs at the most. also, i have extra weight under the front bow lining with wood reinforcement of the same nature to give support to stand/sit atop the the front, with non skid surface and a casting butt seat. Think of it as converted mini bass boat. there are two deep cycle trolling batteries underneath the front.

could adding a hydrofoil wing onto my outboard get more of my front end out of the water? im trying to figure out if it improves planing of the boat, both front and rear. Or do you think i will need to get an aftermarker trim/tilt system like the CMC to trim the motor and get the front end up a bit more out of the water? finding a trim other than aftermarket setup is nearly impossible for my year and power rating of the Evinrude. also, i will need to update the old traditional cable steering to something else, to suit the setback of the the aftermarket trim system that mounts to the transom, which adds a 6" setback.

If a hydrofoil will help, id rather just got that route. but unsure if it will help me at all or even make the front end drag worse. The boat isnt rated for much more than a 40HP motor so a stronger motor is probably not an option. plus we all know what a good 50-60hp motor costs, and trying to find a shortshaft of this size is nearly impossible these days.

any suggestions on how to improve my performance in the water and how to get the front end up higher out of the water to cut down the cutting drag and huge front wake would be greatly appreciated. thanks.

 

actually, i was thinking about the motor pin after i posted this. this morning i went to see where the position is. its on the last hole furthest from the transom giving it the straightest position parallel to the transom. should i try moving the pin up a hole? moving the pin up in notches towards the transom, does that make the rear of the motor tiilt upwards or will it slope more which will change the prop angle? i guess i can just go see for myself. the boat doesnt porpoise or bow doesnt rise. it just currently rides straight thru the water, cutting the water up front, creating the front wake walls of water. for me to acheive better planing of both rear and the front, what angle would you suggest the motor/prop be? rear end of motor tilting up a few degrees or tilting down?

i am considering a tilt/trim aftermarket system so once up and away, i could trim the motor to whatever angle suits best for the speed and conditions, getting the front of the boat more out of the water,but not to where it creates too much bow rise and starts to bog down the rear and porpoise.

most boats i see similar to mine in size,weight and power seem to ride less up front and more towards the middle of the boat, which seems to have less resistance in the water while moving. high power bass boats and river jet boats seem to skim only the rear of the boat, with very minimal hull contact to the water up front. i know i will never get this in my hull design and only pushing 40 horses, but i would think i could atleast get a little bit of the front end that slices thru the water up a bit. thats what i want to acheive.

you did not mention if you think a hydrofoil wing on the motor would help or not. please let me know what you think.

 

the pin for the motor is set to the last hole away from the transom which is the highest point. moving the pin inward (lower) tilts the motor rear end down which would point the prop downward as well. this would be useful if the boat had bow rise and trouble planing, so this does not help me, right?

 

In answer to your last question first.... no a foil on the motor is unlikely to improve matters - in fact it is more likely to make them worse. The foil will create lift at the transom, which will tend to bury the bow further.

If the motor is tilted out to the last pin, I'd start, as Tom suggested, by moving evrything that can be moved - including yourself - as far aft as possible. If that helps then it's worth going on. You will then have to figure out which things can remain there....
It sounds like you have one of two problems:
1. the bottom of the boat has what's called hook. If you look along the 'keel', the middle will be higher than the two ends. If that's the case, you will never make the boat go faster. Live with it, or sell it.
2. The transom wasn't built at the correct angle to accept your outboard. Most transom are set at an angle of about 13 degrees from vertical. If yours is much more than this, you could try packing out the bottom of the outboard bracket by fitting a wedge shape plate (thicker at the bottom). this will give the same effect as having more pin holes on the bracket.

Personally, I suspect that it is more likely to be hook. In which case you'll either have to put up with it or sell....

 

try a post of a pic of my boat. dont know if you can determine if this boat hull has the "hook" you guys mention. the transom that was rebuilt used the original fiberglass outer skin, and inner skin was cut like a window, new wood set it, and refiberglassed, so the original angle of the transom should be as it always has been. this boat is a 1950something Performer made by US Fiberglass products. If hydrofoil would not help or make things worse, what about the more expensive way of putting trim/tilt system to acheive different angles while under way on the water? this route would cost me around $700 for trim unit and new steering system.

 

by the way, we you say move things "aft", does that mean to the back or front of the boat? dont know all terms. sorry. I have 3 total marine batteries aboard. where is the best location for the batteries?

 

So I never heard the term "aft". maybe you havent really met a lot of people then. I am not into boating mumbojumbo terms. It's, left,right,foward,backward,front,back,slow,fast,go,stop. And obviously i need some help,or else i wouldnt be asking for it here on this forum. So even though I might be unfamiliar with some terms, that dont mean I cant figure stuff out with a bit of advise. I rebuilt the boat from nothing basically, put in new transom wood,did all the fiberglassing,wired everything on the motor,changed long shaft to short shaft,impeller and carb,built the trailer,painted the boat, constructed the rear casting deck and front bow support, and everything in between. I have received much advise of forums like this one online to do a lot of the work myself.

Im sure you didnt mean any put down, but all you had to say, was "aft means to the back end of the boat", question answered and no further remarks needed.

anyways, so should i relocate the two deep cycle batteries up front to the rear under the deck? besides the starting battery and fuel tank, i have been using the extra space underneath for life jackets,ropes and such.

Once again, the problem is that the front of the boat when moving thru the water throws large wake to both sides of the front of the boat,rising above the boat. because the water wake is slighty to the front of driver/passenger when you are moving, sometimes we will end up with a pretty good soaking on windy days or choppy water. I was wondering how to get a little of the front hull of the boat riding in the water with a bit less bite and resistance, and hopes to reduce the front wake a bit, if it is possible.

No, there is not trapped water up front, i have drain plugs and bilge pumps to get rid of any water the boat make take in for whatever reason.

 

Aft = rear

 

No need to get upset mate - we were just away for the weekend!

as antonfourie said - aft means the back.

For some reason Tom's most recent post doesn't appear on the board - though I got email notification of it...

Unfortunately we can't tell if the bottom has hook in it from the picture you posted. It's something you would need to check yourself. Get someone to hold a piece of sting to the bottom of the transom - at the keel. you hold the string at the keel further forward - just before it curves up to the bow. With the string pulled tight, if there is a gap between the bottom and the string, then the boat has hook.

 

Why do you have 3 batteries on board?
...and yes - you should try moving all of them - and anything else you can find to the back

 

thanks guys. my fishing partner's father told me it was the old design of my boat (1956-58) and not much will help with the front wake. he also had a boat similar to mine and said it did the same thing.

i will soon move the front two batteries to the back. i have 3, 1 for starting motor,and for the electric shift, the other two for trolling,lights,bilge pumps,electronics and such.

 

It sounds to me like you have a lot of weight on a 13 foot boat. Heavy, little boats don't plane well. First off, as was said move everything you can, including yourself aft, uhhh .... back as far as it will go. Batteries and fuel tank should be back against the transom; that's the back end of the boat where the motor hangs. If you have a console and a wheel, controller etc, move them back too if you can. If they are on one side of the boat you are going to have a balance problem as well. So make sure you distribute things to each side so that when you are sitting in the boat, it sits prety much level and doesn;t lean a lot ot one side or the other. This will help.

The reason for moving the weight is that planing hull boats need to have the center of gravity and center of force (the upwards force to make the boat plane) as far back as possible to reduce the wetted surface (the part of the boat that's in the water) when it is on a plane. Think of it this way. If you take a flat board and push it through the water, it just shoves water aside and doesn't go very fast, but if you take the same board tilt the front end up a little and give it a hard shove, it will skim across the water. That's planing.

The other thing you need to do is reduce weight. Those three batteries together probably weigh 150 pounds. get rid of one. That will eliminate 50 pounds plus the weight of a strap or box to hold it down. Use either the starting battery or the battery for the trolling motor to light the lights. The use so little current your won't notice the drain and you probably aren't out after dark anyway If the battery for the trolling motor is up front move it to the back and get a longer cable.

Plus that, by using standard grade lumber you seriously over built this boat. Go get yourself a 2 inch hole saw and start cutting holes in those two by fours. It's amazing how much weight you can take out and still have a strong structure. 30 to 40 pounds as you said doesn't seem like much but it's lot in 13 foot boat and where it is placed will make a big difference. Any weight you can get out of the forward end of the boat will help a lot.

You don't need power trim but you do need to tilt that engine back more (the propeller should be angled out away from the transom) This will force the bow up. Experiment with wood wedges until you get it right.

As some one said you need to see if the bottom is perfectly flat in the back four or five feet of the boat. This is the surface it planes on. It needs to be flat. Get yourself a straight edge. Make sure it is straight. You can get a metal rule four feet long or more at Home Depot or any hardware store. Place this on the bottom pointing from the back to the front. If the bottom is not straight you need to make it straight. This is easier to do if it has a hook (concave, that is, bends in) than if it has rocker (convex, curves out) This is often called blue printing the boat. If it has a hook you can fill and sand. If it has rocker you need to find some way to get the bottom straight. Take it to a marine repair place or a marine dealer and ask them to show you how.

By the way. Weigh your boat first just the way it is. Take it on the trailer to a truck scale. Weigh the boat and trailer. Then go put the boat in the water and come back and weigh just the trailer. Subtract the trailer weight from the boat weight. Now you know how much you have. Each time you take something out of the boat weigh it. Add up the weights. This will give you how much weight you took out of the boat. You will be shocked at how much your boat weighs and surprised at how much you can take out. Anything you don't need, especially that cooler full of beer (just kidding) needs to go!

Oh. also after looking at the pic, that trolling motor alone probably ways 50 or more pounds and it's hanging right on the bow. (the pointy end.) Take it and its battery, and foot treadle off and go out and run your boat. I'l wager you'll see an immediate difference

 

as well as weight which has been covered, it sounds like motor trim
if you are able to put up a photo of the side view of boat, taken level with the bottom of the boat with motor down. we can then say if it is basicly at the right height and trim
this might tell you a bit more,
http://webfishingclub.proboards57.com/index.cgi?board=boatsafety&action=display&thread=1138321124