Correct Set Up For Small Fishing Boat

[Blue Mesa]

I decided that I should probably put this into a new thread, because we were getting away from the topic on my right turn thread. In addressing that issue, I was asked to post some pictures of the set up on this boat, so here are a few.

I use this boat mostly for fishing, but at the same time I would like to have as much power and efficiency as can be expected from a 14' aluminum boat and a 1981 25 hp johnson motor. I am new to all of this so any input would be helpful. I have read a lot of posts on this site recommending the removal of hydrofoils. I took this one off, and I will try the boat out without it later today if the weather cooperates. But i do notice that a lot of fisherman around here have hydrofoils on boats and motors around this size. They say it works better for trolling. So I guess I'm asking for opinions here.

Here are a few photos of the motor set up. The first pics show it as I have been running it, with the hydrofoil and set on the lowest tilt setting. The last ones show it the way it is now. I have removed the hydrofoil, and moved tilted the motor out one notch.

What I noticed: The hydrofoil/anti-cav plate is a little over 2 inches below the bottom of the boat - Is that too low?

With the motor on that lowest tilt notch, it it is well beyond level - pointing up (pushing the bow down).

Even after moving it up a notch, it is still going to push the bow down some.

I thought this was probably as much as I should change until I get to try it, but I would really like some opinions here. i don't know why my father in law set it up that way, and I don't think he would remember at this point. So tell me what you see.

Thanks

 

[tashasdaddy]

Re: Correct Set Up For Small Fishing Boat

i would put a 3/4 inch shim on top of the transom. is this a tiller or remote controlled motor. would like to see complete boat. before going further.

 

[Blue Mesa]

Re: Correct Set Up For Small Fishing Boat

i would put a 3/4 inch shim on top of the transom. is this a tiller or remote controlled motor. would like to see complete boat. before going further.

It's a tiller. It's a very basic 14' crestliner from 1981. 4 seats, I have the front one out. All I have done so far is replace the plywood decking and repair some of the seats. It needs quite a bit of cosmetic work because it sat uncovered in the sun for the last couple of years.

I had wondered about building some kind of shim for the transom because the motor just clamps on. Could I just use treated lumber for that? Would it need to be screwed on, or could it just sit there?

I'll be glad to take a picture of the whole boat later. You want it from the side?

 

[tashasdaddy]

Re: Correct Set Up For Small Fishing Boat

just cut a 1x2 and slip it under the motor. clamps tight, but don't break them. you can see the 1x2 under this 15hp made a big difference.

this little 14 footer would run 25 mph. i also added controls and stick steering to the middle seat.

 

[Blue Mesa]

Re: Correct Set Up For Small Fishing Boat

Tashasdaddy - what do you think about the hydrofoil? Good, bad, indifferent? Did you make that frame for the cover? I am going to need to make something for this boat for winter. It will have to sit under many feet of snow. It has some brackets built in just below the gunwale that I assume are for some kind of cover frame. I may try to use those and make some type of strips to hold the cover up. PVC is a good idea though.

 

[tashasdaddy]

Re: Correct Set Up For Small Fishing Boat

i have made many of the pvc tent frames. they work like a charm. you could beef it up for snow. but we don't have that problem here. i hate hydrofoils, but with the tiller operation, it might help get the stern up. but not much. they ususally cause more problems, than they help. that transom look like it needs some attention also.

 

[Silvertip]

Re: Correct Set Up For Small Fishing Boat

Using a hydrofoil for trolling is useless. You are trolling! A foil is added to a boat to aid in stern lift, assist in getting on-plane, controlling porpoising and allowing a boat to stay on plane at slower speeds. You are doing none of these when trolling. I think what you may have seen is a "trolling plate" which is installed on bigger motors and is a hinged affair that allows the plate to drop down in back of the prop so slow the boat. Bigger motors sometimes don't troll slow enough so the plate helps slow it down. The pin you are playing with is the tilt pin and is not what is used to position the AV plate. Engine height on the transom is what determines that which is what Tash is explaining.

 

[CATransplant]

Re: Correct Set Up For Small Fishing Boat

As far as covering your boat goes in the winter. I'd do what I do. I pull the engine, and everything else I can remove from the boat, then turn it upside down on the trailer. Then, I block the trailer axle so the tires are off the ground, and call it good. I store the outboard in my basement, along with the trolling motor and battery.

If you do that, you can simply forget the boat for the winter, no matter how deep the snow gets. In the springtime, even before the ice is off the water, you can flip the boat back over and start your work on it before it's time to go fishing.

While the outboard's in the basement (I clamp it to the big old concrete laundry sink down there), it's a good time to do a nice cleanup and tune up for the next spring. Gives you something to do when you can't go boating. Keep the battery charged up all winter, and that sort of thing.

 

[Blue Mesa]

Re: Correct Set Up For Small Fishing Boat

Using a hydrofoil for trolling is useless. You are trolling! A foil is added to a boat to aid in stern lift, assist in getting on-plane, controlling porpoising and allowing a boat to stay on plane at slower speeds. You are doing none of these when trolling. I think what you may have seen is a "trolling plate" which is installed on bigger motors and is a hinged affair that allows the plate to drop down in back of the prop so slow the boat. Bigger motors sometimes don't troll slow enough so the plate helps slow it down. The pin you are playing with is the tilt pin and is not what is used to position the AV plate. Engine height on the transom is what determines that which is what Tash is explaining.

Yeah, that makes sense to me. The guy I talked to the other day did have a plastic hydrofoil very similar to the one that was on this boat. This was on a boat a little smaller than this one with a 15 hp johnson. But, I won't even try to relay the explanation he gave me about why he uses it and what it does, but it didn't make any logical sense to me. I don't know much about power boats, but I am familiar with kayaks and aircraft and the way fluids flow over surfaces.

I guess I wasn't clear about the tilt thing either. I realize that lifting the motor is one thing, and tilting it with the pin is another. I was going by what I was reading on this site, and thinking that having the AV plate 2.25 inches below the bottom might be too low, so I should find a way to lift it - that got answered. Also, it sounds like I want to start with the AV plate close to parallel with the bottom of the boat, so I tilted it back a bit. As I said, even on that second notch, it is still "trimmed in" a bit, so I thought that might be a good place to start.

Bottom line, with as little as I know, I didn't want to go in and make big changes to the set-up without advise. I know my father-in-law set it up this way for some reason, but he doesn't always pay much attention to the details.

Here is what I'm looking for: We have a fairly big lake, 25 miles long with river arms that extend 7 miles or so off the main lake. I want to be able to get from point A to point B as quickly and efficeintly as possible. When I get there, I will be doing some hiking (doesn't how the boat is set up for that) but I will also be doing some fishing. Fishing is mostly drifting while throwing lures or flies, with occasional trolling.

With that mix in mind, what is a good starting point for set up? It sounds like I am looking for the boat to come on plane fairly quickly, not porpoise at a medium speed, and not have the bow too high when I'm cruising. Obviously making sure the motor is sufficiently in the water for cooling. Is that close?

And finally (sorry this is so long) yup the transom needs work, so do all the wooden seat tops, and the boat needs paint. I'm hoping to get it all done this summer. I bought the spar varnish for it today.

Thanks again

 

[tashasdaddy]

Re: Correct Set Up For Small Fishing Boat

good varnish. ideally the plane of the hull and av plate should be the same. that is the reason new motors now have trim and tilt. but to get out of the hole, you trim a motor all the way down, then as it comes on plane you trim out for speed and efficiency. you do not have that luxury, you have to find the happy medium between getting out of the hole, and speed and efficiency. it really gets down to experimenting with the tilt pin. till you hit the happy spot. also dispersing the load in the boat at different place works well also.

 

[Blue Mesa]

Re: Correct Set Up For Small Fishing Boat

Here are a few pictures of the whole boat. We took it out tonight. I had raised the motor with a 1 X 2, tilted it up/out a notch, and removed the hydroplane. It wasn't pretty. The bow rose much more on initial acceleration, and took MUCH longer to even begin to come down. On the first run, after just a short time, the motor began to rev up and down, I assume it was cavitating. I tried that for a while, then tilted it back down where it used to be. That was better, but the boat was noticeably slower. We moved weight around a bit, but it was always slower than it used to be - not what I expected. I intended to try a couple of other things, but there was a little thunderstorm dumping up the valley from us causing some pretty big outflow winds coming down the river canyon. We came back into some pretty good waves. The boat rode well, but we called it a night.

I think I will set everything back to where it was, except for the hydrofoil removal. From there I will make one change at a time. I also need to be sure this engine is running up to its potential. It starts and runs well, but I have no idea if it is actually revving the way it should etc.

 

[tashasdaddy]

Re: Correct Set Up For Small Fishing Boat

you have the same problem i had. not enough bow weight. thats why i put the remote controls at the middle seat. so i could go out alone. where are you beautiful area.

 

[Blue Mesa]

Re: Correct Set Up For Small Fishing Boat

you have the same problem i had. not enough bow weight. thats why i put the remote controls at the middle seat. so i could go out alone. where are you beautiful area.

Gunnison, Colorado. And those pictures don't show any of the pretty stuff. It's paradise - except for a few weeks of -35 in the winter.

Not enough bow weight. Do you get that from my description or from looking at the boat? That sounds about right. I will be in it by myself quite a bit, so maybe I should put the dreaded hydrofoil back on for now. Something made a huge difference in the wrong direction last night. Too bad I didn't have time to try a couple of tweaks before we had to get off the water.

 

[tmcalavy]

Re: Correct Set Up For Small Fishing Boat

My last boat was like your rig, only with an 18 hp Johnson for power. I used to run it in the first notch out when it was only me and the dog/first mate or the bow would come up too high. With a buddy and the first mate along for the ride I had to run it in the 2nd/3rd notch out or the bow would plow the waves and we'd lose speed. Moving weight into the middle of the boat makes a big difference. My final combination was sitting between the rear and middle seats on a milk crate and using a home-made tiller extension, with the buddy on the middle seat and the first-mate forward. We gained top end and I didn't have to fool with the trim as much...kept it in the 2nd notch out. TD's rig with three seats and stick steering is pretty much ideal for this size boat. You may not need the hydrofoil with 25 hp on the transom, but with a smaller outboard they come in real handy...got my tinny on plane fast but made handling a little doggy/slow.

 

[Blue Mesa]

Re: Correct Set Up For Small Fishing Boat

I am a little confused about the response I got from the boat when I removed the hydrofoil and raised the motor. It began to rev up and down right away, which I assumed meant it was cavitating.

It sounds like I am dealing with a balance issue here as much as anything. I do keep the gas tank in the middle of the boat, and all the gear forward. I am going to give it another try without the hydrofoil since most seem to feel that is a bad thing. It did seem to raise the stern quite a bit though.

As to raising the motor. I attributed the cavitation I experienced last night to that, but it is still really low. People are saying the cavitation plate should be level with or above the "bottom" of the boat. I used a 3' straight edge to measure where it was. Is it better to use something longer, maybe 6 or 7 feet to get more of the hull shape involved?

I am just concerned about raising it too far and doing harm to the motor.

 

[Silvertip]

Re: Correct Set Up For Small Fishing Boat

Lets get this "raising the motor" thing straight. Are you using the tilt pin to simply tilt the motor or are you physically MOUTING the motor higher on the transom? If its the former, you are doing it wrong. Thats a trim adjustment that adjusts the attitude of the boat while on plane. Height adjustment refers to getting the AV plate (its not a cavitation plate) flush with the bottom of the boat when the engine is perfectly vertical.

 

[Blue Mesa]

Re: Correct Set Up For Small Fishing Boat

Lets get this "raising the motor" thing straight. Are you using the tilt pin to simply tilt the motor or are you physically MOUTING the motor higher on the transom? If its the former, you are doing it wrong. Thats a trim adjustment that adjusts the attitude of the boat while on plane. Height adjustment refers to getting the AV plate (its not a cavitation plate) flush with the bottom of the boat when the engine is perfectly vertical.

I did both, but what I was reffering to was raising the motor with a block of wood on top of the transom. I only raised it 3/4" so that should not have caused the problem. I can probably raise it about 1 1/2" and still get a good grip on the transom. I just want to be sure I'm not risking losing the flow of water to the intake.

Thanks for the correction on the AV plate terminology. What does AV stand for? I'm trying to understand what that plate actually does.

 

[tashasdaddy]

Re: Correct Set Up For Small Fishing Boat

i would not block it up higher than last night with the 3/4 block under it. you water pick up is the red area marked and the screen in front of it. the water pump is located by the blue. yes, the balance is what you are after. click on picture to enlarge.

 

[Tacklewasher]

Re: Correct Set Up For Small Fishing Boat

Thanks for the correction on the AV plate terminology. What does AV stand for? I'm trying to understand what that plate actually does.

Anti-ventilation.

Most of the time, when people talk about cavitation, they really mean ventilation.

Cavitation is when the prop creates air bubbles.

From wikipedia http://en.wikipedia.org/wiki/Cavitation

"As an impeller's (in a pump), or propeller's (as in the case of a ship or submarine) blades move through a fluid, low pressure areas are formed as the fluid accelerates around and moves past the blades. The faster the blades move, the lower the pressure around it can become. As it reaches vapor pressure, the fluid vaporizes and forms small bubbles of gas. This is cavitation. When the bubbles collapse later, they typically cause very strong local shockwaves in the fluid, which may be audible and may even damage the blades."

Ventilation is when the prop sucks in surface air. Usually running too shallow.

I'm going to go against the flow a bit here and suggest you put the fin back on. Or find a smaller fin (that one is huge for the motor) for cheap and try it. Leave the motor lifted up the 3/4 inch and in the second hole. See if the fin will help. You'll lose top end speed but may prefer the overall performance.

Most of the time, these fins are put on bigger boats that really should have trim tabs. That is where most of the comments to remove them come from. You would never put trim tabs on your boat.

 

[Blue Mesa]

Re: Correct Set Up For Small Fishing Boat

I'm going to go against the flow a bit here and suggest you put the fin back on. Or find a smaller fin (that one is huge for the motor) for cheap and try it. Leave the motor lifted up the 3/4 inch and in the second hole. See if the fin will help. You'll lose top end speed but may prefer the overall performance.

Most of the time, these fins are put on bigger boats that really should have trim tabs. That is where most of the comments to remove them come from. You would never put trim tabs on your boat.

I am kind of leaning toward trying this since the fin does seem to lift the rear of the boat quite a bit. She's never going to be a racer, but I would like some efficiency.

Could you recommend a particular fin manufacturer, or are they all about the same?