Hard starting Yamato 102

[ZUL8TR]

Traps

johnsonm50 & ZUL8TR, ...

It all sounds good, ... I want to put a couple of coats of epoxy to them first before they go on. The only thing is, ... I just hate the idea of just screwing them on temporarily. The thought of screwing them in and out for adjustment cuts leaves bare wood (screw holes) vulnerable to water contamination inside the holes and weakening of the chine log until the piece is finally glued on.

I do understand that it will be easier to remove then, join them together with double sided sticky tape and the adjustments all at once, but I think it would be simple enough to do them accurately and separately while being attached to the hull.

Would it be safe to say that because it's of a shovel nose design, it's probably going to have more lift than if it was of a more modern design?

If that's the case, ... is there a good possibility some of the trimming is already known from your past experience and could be done before permanently affixing them?

OR, am I just being to critical?

Thanks Guy's

Bill

Bill

Based on the cost you note to do the running just screw and glue as you presently have them made, run the boat and have a video taken of a fly by at full open then post it here and suggestions will be made. When doing this have the prop shaft dead level with the bottom rear planning surface. Engine height set for your prop and rpm (shoot for about 7000 with the Yamato).

Back in the 50's, 60s' hydros came with removable air traps so the owner could dial it in, and also change sizes for different conditions. When I raced traps were built into the boat and the removable traps went away.

Back in the late 1970's in APBA racing I ran a Y80 on my Wetback in 20SSH also a Merc 25ss in 25ssh (the pic I sent you) and in both classes competition speeds were over 60 so that Yamato on your boat when finally dialed in is also capable of that and things happen very quick at those speeds so BE SAFE.

[ZUL8TR]

set up

Hi hybroid,

Yes, it's a 10'2" big brother to the Tiny Titan. Kicking out proved to not be the answer, ... it resulted in taking forever to get it up on plane. Hence, ... adding the air trap.


A Lee Tietze fin is on, ... and down. In fact, I wonder if I have to much fin hanging down, 6.5" below the sponson. A couple of reasons to why I am leaning on the wheel. 1st It's the pivot point and 2nd, ... I didn't know any better until I was just recently told I am sitting to far forward.


I was wondering if I should hold off on installing the air trap until I tested it with me kneeling in the correct position, but as you and others have noted, ... this design doesn't have much lift if any at all and it the reason for adding the air trap.

As far as the yellow, ... It's a lake racer and I wanted to be as visible as possible considering how small the boat is.

Thanks
Bill

Bill

The fin depth you note is deep but leave it alone till after the traps are on because if the lift gets there the sponsons gould easily be 2" above the water. Then you can play with the fin position once you learn how to set the boat in turns and moving about in the cockpit.

[BillCNC]

Bill

Based on the cost you note to do the running just screw and glue as you presently have them made, run the boat and have a video taken of a fly by at full open then post it here and suggestions will be made. When doing this have the prop shaft dead level with the bottom rear planning surface. Engine height set for your prop and rpm (shoot for about 7000 with the Yamato).

Back in the 50's, 60s' hydros came with removable air traps so the owner could dial it in, and also change sizes for different conditions. When I raced traps were built into the boat and the removable traps went away.

Back in the late 1970's in APBA racing I ran a Y80 on my Wetback in 20SSH also a Merc 25ss in 25ssh (the pic I sent you) and in both classes competition speeds were over 60 so that Yamato on your boat when finally dialed in is also capable of that and things happen very quick at those speeds so BE SAFE.

Now that's the answer I was looking for, ... Not that I was being lazy, in case you may not have noticed, ... I can get pretty anal over details, ...

Thanks Pete

Bill

[BillCNC]

Bill

The fin depth you note is deep but leave it alone till after the traps are on because if the lift gets there the sponsons gould easily be 2" above the water. Then you can play with the fin position once you learn how to set the boat in turns and moving about in the cockpit.

Got it, ... I can simply machine it down if needed, ... I sometimes get board during lunchtime at work.

[ZUL8TR]

fin

Got it, ... I can simply machine it down if needed, ... I sometimes get board during lunchtime at work.

Or you could drill several vertical holes in the fin (not the bracket) and raise the fin via the holes. That is the way I set them up.

[johnsonm50]

[QUOTE=BillCNC;213380]johnsonm50,

I wasn't referring to shovels as being faster, ... just in having more lift. It seems that would be the reason the Pickle came to be, ... to eliminate unwanted lift.

Experimentation is always good and most of the time needed. Basically it's just a straight line from 1/4" below the sponson's to flush with the bottom of the hull at the transom. 3-1/16" high at the sponson's and 59-3/8" long.

I was just trying to find out if any mods to the basic design he sent me would already be know and could be immediately addressed now to eliminate unneeded trips for just testing the air trap. It's $50 for each trip just to get on the lake and not including travel expenses. $10 for the boat, $10 for the trailer and $30 for renting a chase boat for the first 2 hours. ouch.. pretty steep.

[BillCNC]

I finished making a tool to check my motor angle and height. It showed me one thing, ... My motor height and angle were all off.

I have used the original shim setup that I got with this motor to try different settings. I found that by removing a plate in the setup, I could level the motor angle and then raise the engine another 1/4". I think it comes out pretty well. There is a 1/8" gap at the forward tip of the jig and the transom is flush with it. That stretch is 14". The center of the shaft is 3/4" below the bottom of the hull.

Should this be a better place to start?

[ZUL8TR]

angle

I finished making a tool to check my motor angle and height. It showed me one thing, ... My motor height and angle were all off.

I have used the original shim setup that I got with this motor to try different settings. I found that by removing a plate in the setup, I could level the motor angle and then raise the engine another 1/4". I think it comes out pretty well. There is a 1/8" gap at the forward tip of the jig and the transom is flush with it. That stretch is 14". The center of the shaft is 3/4" below the bottom of the hull.

Should this be a better place to start?

I would make it level to start as a zero base. Get rid of the 1/8" kickout gap. Your checking device needs to be trimmed so there is additional clearance of the forward blade over 14 or so inches for other vertical positions of the engine.

[BillCNC]

I would make it level to start as a zero base. Get rid of the 1/8" kickout gap. Your checking device needs to be trimmed so there is additional clearance of the forward blade over 14 or so inches for other vertical positions of the engine.

It will be level after I make some new angle blocks today, ... .750" I will also make a set of .725", ... That should get me in the ball park for the final set's measurements..

As far as trimming the tool, ... I'm not sure I follow you. Could you make a quick sketch?

Bill

[ZUL8TR]

Tool trim

It will be level after I make some new angle blocks today, ... .750" I will also make a set of .725", ... That should get me in the ball park for the final set's measurements..

As far as trimming the tool, ... I'm not sure I follow you. Could you make a quick sketch?

Bill

Here is a sketch. On the tool you made I presume because the blade is bolted to the block that goes on the prop shaft it is slightly adjustable to get the blade measuring edge exactly parallel to the hole centerline you drilled to fit the prop shaft? If not you need to make it true to be that way.

[BillCNC]

Ok, ... I see. The tool as pictured, ... the center of the shaft is exactly .750" below the blade. I loosen the cap off and install the tubular shim and tighten the cap down, ... perfectly centered.

I figured I would rest the blade on the bottom of the hull then the center of the shaft is exactly where it needs to be. The red mark on the blade is 12" from the tip of the blade, then the blade extends another 2" to the back edge of the transom.

Bill

[BillCNC]

Whoo-Hoo!!!!

Someone brought me a life Jacket. Hmmm, ... certified 2 months ahead of time 2-13.

"Great Scott", ... I wonder if the UPS guy has a "Flux-Capacitor" installed in his truck?

Jacket pictured with the air trap rails.

Bill

[ZUL8TR]

angle tool

Ok, ... I see. The tool as pictured, ... the center of the shaft is exactly .750" below the blade. I loosen the cap off and install the tubular shim and tighten the cap down, ... perfectly centered.

I figured I would rest the blade on the bottom of the hull then the center of the shaft is exactly where it needs to be. The red mark on the blade is 12" from the tip of the blade, then the blade extends another 2" to the back edge of the transom.

Bill

Regardless if I was using the tool I would trim it as I sketched to allow more flexability with adjustments with different engine heights and angles.

[BillCNC]

The trap was added, ... and now the boat is VERY squirrelly like the back is loose, ... if we where talking about a car. In the video you can hear me back off the throttle because the back end started wagging and almost tossed me out at one point. That was not on video so I tried to recreate it for the video. The steering is tight, the motor was tight and the lower end was roped down. I don,t seem to be getting the sponson's flying and it took a bit to get the prop to grab and get me up on plane. Laying on the cowl was needed and boy, ... it's sure hard to see in front of me with a helmet on when laying down.

I think that the motor still might be high even though I was getting water out of the tubes. It sure made it tricky to turn around and look with the helmet and the boat being very responsive at the well.

The turns were waggy.

http://youtu.be/tcjPDEot-3s
http://youtu.be/g7lzalnv0u8
http://youtu.be/_9UU5MjQz9E
http://youtu.be/jYYPdwPkdbE

[bill van steenwyk]

You are doing a very nice job with...............

.........the wood and accessory construction. I also like the life jacket you have, as safety is paramount when you are running the boat, whether racing or just "running", as has been pointed out and you have acknowledged.

I have not been following all the changes/suggestions the last couple of pages of posts, but if you are confident your motor is NOT too high, prop shaft relation to boat bottom wise, and the "squirrley" (back end loose) condition started right after installing the air traps, then the next logical step would be to trim the air traps a little. By trimming them I mean the following:

You picture the boat upside down. Take a chalk line or straight edge and go from the back of the air trap to maybe half way the length of the trap toward the front of the boat, from maybe a 1/4" to nothing. Mark this off with the chalk line or a pencil. Remove with a wood rasp or plane. It will go very quick because you are not taking much. Then test. If still too "loose", then remove a little more, and taper it to nothing a little further forward. I understand it is costly for you to test, but if you would make several adjustments at a time if the 1st was not enough, you could do others right at the lake on the trailer. You might want to apply some poly sealer after the rasping and before putting in the water. If it were me I would make all these tests from now on out with the prop shaft parallel to the boat bottom, at the 5/8" to 1/2" depth, unless you have found that not to be satisfactory. Get your air traps dialed in now, and then you can play with motor height and angle.

The object is to take it in small steps, as it is much easier to remove material than add it, although if you find you have taken too much, it is easy to add back with a 1/4" thick piece of aluminum sheet, attached to the outside of the trap.

Unless you changed something else, (motor height, etc) the problem that usually causes the back end to be loose, is the back end of the boat being too high causing the prop to slip some and break loose. It sound likes this is what may be happening now after adding the air traps, as that puts extra lift (air) under the back of the boat. A little can do a lot as you are finding out.

Good Luck