Tinny Problem

[gazza2006au]

i bought another tinny yesterday, when the seller said go easy when turning i didnt think much of it
today while out on the river under full power from the 25hp engine we were almost thrown from the boat as the boat tilted from left side to right side and back and forth, while at around half throttle it behaved but would still do the same thing but i had most control over it
how do i fix this problem?

the actual word is "the boat listed" im not great at describing things and i thought i'd ask on this forum to get a bigger and better reply hopefully to solve the problem

[joey_1987]

Does it have a foil or any sort of device fitted to it?

[cormorant]

Where is the cav plate in relation to the bottom of the hull?

[burleygu]

is the motor on straight and center?

[Chimo]

Gazza

My tinny used to do the same thing when you moved the tiller (felt really unsafe, like it was going to flip) so I fitted a set of foils and problem solved and they made it turn flat like an MG A or B series.

Cheers
Chimo

[gazza2006au]

Does it have a foil or any sort of device fitted to it?
no foil mate

Where is the cav plate in relation to the bottom of the hull?
good idea i didnt think to check this so i just went and looked the cav plate is 2.5inches lower than the hull

is the motor on straight and center?
yup shes on center

Gazza

My tinny used to do the same thing when you moved the tiller (felt really unsafe, like it was going to flip) so I fitted a set of foils and problem solved and they made it turn flat like an MG A or B series.

Cheers
Chimo
Chimo i think im going to add foils just because its such a small tinny 3.81m and i usually fish 1-3 people and the 3 of us are 100kg blokes so it'll stabilize it in turns as u mentioned, what brand did u go with?

[Chimo]

Gazza

Can you lift your motor too? Doing that will also help to improve the efficiency of the boats operation.

I've used a number of different foils over the years as per the pics95904959059590695907http://www.ausfish.com.au/vforum/images/misc/pencil.png

[Fed]

I'd try raising it up before first.

[gazza2006au]

Gazza

Can you lift your motor too? Doing that will also help to improve the efficiency of the boats operation.

I've used a number of different foils over the years as per the pics95904959059590695907http://www.ausfish.com.au/vforum/images/misc/pencil.png

yeah i can lift the engine but im not sure if that'll effect the steering as the steering cable is already angled up a little so add another 2.5" i might be in trouble
i dont plan on keeping this engine but i will use it for the time being untill i get another engine shouldi leave it as is or go to the effort of moving it up welding the holes etc..?

forgot to mention its a 15" transom with a 17.5" engine :-?

[gazza2006au]

I'd try raising it up before first.
thanks Fed thats the exact problem

[Gon Fishun]

Looking at the angle of the motor to the the transom, does the boat get the bow up when under way or does it tend do drive nose down.

[WalrusLike]

Your motor looks way too low to me.

Try lifting first. Maybe get cav plate a inch or two higher than keel.


(Using Tapatalk on iPhone so can't easily 'thank' or 'like')

[cormorant]

Accident waiting to happen gazza. Get height sorted properly ( may take a inch or 3 - who knows) so you don't capsize your new boat at speed for a start is my initial thought. It may have had a long shaft fitted due to other bad handling characteristics or didn't know any better or just bought a 2nd hand replacement box and bolted on so I won't say change shaft length yet. Wear your safety lanyard. Check out all your steering linkages and also the prop torque tab behind the prop are set up right and finally check the shape of the planing surfaces on that hull. Hook on one side of hull from being strapped down too hard or beached etc can cause similar handling issues. Do your testing very cautiously and stay off the plane until you get it properly sorted. The joy of a new boat that wasn't water tested. Great size of boat and brilliant in good conditions around the harbour, bays and up the rivers but beware the low transom with any swell etc Does it leak???

[gazza2006au]

cormorant , yeah its a great little tinny perfect size, we were fishing about 500 meters off port hacking heads in sydney yesterday when we were coming back in is when we almost got tossed out of the boat
we had a small swell coming from the left to right and at half throttle on the plane the boat hooked to the left and got a bit hairy
and no leaks or any hull damage the bloke i bought the rig from owned it for the past 11 years so its had this engine on it for that long and he has two small kids under 6 years old who frequently went in the boat :o

ill look into moving the motor up in the next few days before i take it out again i have a welder and have welded aluminium but not 100% confident but ill give the holes a go

[cormorant]

Hell Gazza - first day out with a new unknown boat and going outside . Hope you partnered up with another boat and took the radio. Weather is just weird at the minute but can't knock it.

Wonder when the bloke replaced the gearbox and if it handled better before that one was on it

[gunna]

Chimo i think im going to add foils , what brand did u go with?

If you search Smithy's posts on foils you will find the brand he recommends. Much cheaper than most and I took his advice. They work fine.

[gazza2006au]

cormorant, yeah we have perfect weather here the swell was only around .5m and far apart it was windy but surprisingly no chop so it was a beautiful day

i just checked and raising the engine is a no go, the engine clamps will be above the transom and the two transom bolts will be right at the very top of the transom

its weird johnson made a 17.5" shaft, when i sell the engine i dont know if to sell it as long or short shaft

gunna, thanks ill search soon

[GBC]

Get onto Solas props in QLD. They do a Long shaft riser kit - piece of poly that bolts into the existing holes and raises your motor. The LAST thing you need on a forward steer tinny is a foil.

[cormorant]

http://www.leeroysramblings.com/OB_shaft_length.htm

[gazza2006au]

Get onto Solas props in QLD. They do a Long shaft riser kit - piece of poly that bolts into the existing holes and raises your motor. The LAST thing you need on a forward steer tinny is a foil.

this one? it doesnt say how tall the converter is though http://www.ebay.com.au/itm/outboard-transom-bracket-6hp-30hp-height-adapter-/300660384630?pt=AU_Boat_Parts_Accessories&hash=item4600c16376


http://www.leeroysramblings.com/OB_shaft_length.htm cheers mate i checked that out and measured the engine its 17.5" not a small shaft and not a long shaft :-?

[GBC]

Yep thats the one. It is to convert a standard tinny transom from short to longshaft - ie using the same bolt mounting holes will raise 150mm. It is just a piece of plastic (albeit strong and heavy plastic) so you can measure your rise and redrill the plastic or redrill your transom (or both if required) for your required lift which looks to be approx 70 - 75 mm from your photo with the tape.

edit - scratch that - just measured mine and the head section is 100mm high so unless you turn it backwards or mill it out 25mm you will end up too high - bugger. It can be made to fit but will need modifying.

Next best is to get a piece of 70mm ally box welded onto the top of your transom and move the motor higher that way? Probaby cost less too.

[gazza2006au]

Yep thats the one. It is to convert a standard tinny transom from short to longshaft - ie using the same bolt mounting holes will raise 150mm. It is just a piece of plastic (albeit strong and heavy plastic) so you can measure your rise and redrill the plastic or redrill your transom (or both if required) for your required lift which looks to be approx 70 - 75 mm from your photo with the tape.

edit - scratch that - just measured mine and the head section is 100mm high so unless you turn it backwards or mill it out 25mm you will end up too high - bugger. It can be made to fit but will need modifying.

Next best is to get a piece of 70mm ally box welded onto the top of your transom and move the motor higher that way? Probaby cost less too. yeah i thought of using the 70mm box aluminium is 3mm sufficient? if so i might try weld it on my self

[GBC]

Sounds somewhere near about right? Ally section thickness isnt my thing. Hopefully someone with the requisite knowledge will step up. Good luck with it all - it'll be a new boat when it's lifted.

[Gon Fishun]

Hi Gazza2006au.
I have a Clarke Comet 3.6 that is designed for a short shaft motor. Long story short, I have fitted a 9.9 merc long shaft to it and it travels ok, but I wanted to raise the motor and get it closer to where it should be. Spent a weekend with 50 x 50 x 3mm box and 50 x 25 x 3mm rectangle and built the transom higher. I had it bolted and braced but found there was to much flex in all of it. Had it been welded it probably would have been ok. I found 3mm thick alloy was ok. If you are going to weld it to the top of the transom you might need a gusset or brace for support and I would make sure you bolted the motor through the transom as well for support.

[gazza2006au]

Hi Gazza2006au.
I have a Clarke Comet 3.6 that is designed for a short shaft motor. Long story short, I have fitted a 9.9 merc long shaft to it and it travels ok, but I wanted to raise the motor and get it closer to where it should be. Spent a weekend with 50 x 50 x 3mm box and 50 x 25 x 3mm rectangle and built the transom higher. I had it bolted and braced but found there was to much flex in all of it. Had it been welded it probably would have been ok. I found 3mm thick alloy was ok. If you are going to weld it to the top of the transom you might need a gusset or brace for support and I would make sure you bolted the motor through the transom as well for support.
ah so u had the same problem im having ;D i plan on TIG welding the alloy in place im not sure if stitch or full welds are needed? it might be a bit hard welding outside its windy here today
should i weld a full length of allow cut and shaped to suit the sides of the transom or will a small piece the width of the engine be ok?
do u have a picture of a brace i can copy?

heres a few more pictures i just took of what it is now

[Gon Fishun]

ah so u had the same problem im having ;D i plan on TIG welding the alloy in place im not sure if stitch or full welds are needed? it might be a bit hard welding outside its windy here today
should i weld a full length of allow cut and shaped to suit the sides of the transom or will a small piece the width of the engine be ok?
do u have a picture of a brace i can copy?

heres a few more pictures i just took of what it is now

I only had mine bolted, which wasn't strong enough, so I pulled it all back off. No pics sorry.

I don't know enough about aluminium welding, do you, (no reflection on your capabilities) but you would need a strong weld on a 70mm piece of ally on the top of the transom. The top motor bolts would be attached to it and the lower bolts through the transom. There would be a far bit pressure on it. Just had another look at your transom and there is only the 2 bolts and the clamps holding the motor on. Depending on funds I would remove the backing and make up a complete new plate out of aluminium 70mm higher ( if thats what it needs ) with the 70mm block welded to the front side, sitting on the top of your transom. Use the old one as a template. You could try just the block to raise it but I wouldn't think it to be very strong.
Cheers .
Bob.

[gazza2006au]

I only had mine bolted, which wasn't strong enough, so I pulled it all back off. No pics sorry.

I don't know enough about aluminium welding, do you, (no reflection on your capabilities) but you would need a strong weld on a 70mm piece of ally on the top of the transom. The top motor bolts would be attached to it and the lower bolts through the transom. There would be a far bit pressure on it. Just had another look at your transom and there is only the 2 bolts and the clamps holding the motor on. Depending on funds I would remove the backing and make up a complete new plate out of aluminium 70mm higher ( if thats what it needs ) with the 70mm block welded to the front side, sitting on the top of your transom. Use the old one as a template. You could try just the block to raise it but I wouldn't think it to be very strong.
Cheers .
Bob.
Bob im actually new to the whole TIG welding aluminium process i have around 4 hours up my sleeve but i can weld ok these are some 40x3mm tubing i welded for a bait tray, i figure i bought the welder for my boats so i better use it worse case i i just remove what i weld on and take it to a shop

[Matt76]

They look pretty good for a home job Gazza, well done. Maybe just a touch more heat (power) needed in the first few pics. Welding the old aluminium of the boat will be a whole different story, you would need to sand it right back to good material if its possible, to get it as clean as you can. If it were mine I would probably get someone with a good ally mig to do it as a good mig will be far less bothered by the impurities of the old ally.

[Gon Fishun]

Bob im actually new to the whole TIG welding aluminium process i have around 4 hours up my sleeve but i can weld ok these are some 40x3mm tubing i welded for a bait tray, i figure i bought the welder for my boats so i better use it worse case i i just remove what i weld on and take it to a shop
What Matt76 said is good advise.
I'am a bit of a bush mechanic and have been referred to as Bodgey Bob occasionally, but if I could weld aluminium like you, I would do it. If you do have a go I'd be inclined to fit a wider bracket and angle supports near the motor bracket ( like the one in the middle inside of transom) to give it more support.
Cheers.

PS is your motor tilt on that last hole or do you tilt it out.

[gazza2006au]

They look pretty good for a home job Gazza, well done. Maybe just a touch more heat (power) needed in the first few pics. Welding the old aluminium of the boat will be a whole different story, you would need to sand it right back to good material if its possible, to get it as clean as you can. If it were mine I would probably get someone with a good ally mig to do it as a good mig will be far less bothered by the impurities of the old ally.
thanks matt, i wasnt using the foot peddle for those welds just set the amp and away i went stopping to increase amp's a little at a time untill i got the alloy to melt

[gazza2006au]

What Matt76 said is good advise.
I'am a bit of a bush mechanic and have been referred to as Bodgey Bob occasionally, but if I could weld aluminium like you, I would do it. If you do have a go I'd be inclined to fit a wider bracket and angle supports near the motor bracket ( like the one in the middle inside of transom) to give it more support.
Cheers.

PS is your motor tilt on that last hole or do you tilt it out.back yard bob sounds better than bodgey bob LOL ;D the pin is stuck on that second hole i tried tilting it out this afternoon shes not moving for anyone :-? if it becomes a problem once i do the transom i might have to cut the pin out and put a new one in if i keep this engine

[Chimo]

After i saw you pictures above I wondered why don't you raise the whole section where the motor sits and make the boat dryer and safer at the same time?

Cheers
Chimo

PS looks like you could do it yourself based on your welding pics. Just make sure you brace the new transom onto the floor at a reasonable angle eg 45 degrees.

[Brisbane Marine]

On that particular engine the water pick up for the motor is in the exhaust outlet tube just under the cav plate. You cannot over raise the engine cause the motor will starve for water. First thing to try is running the engine out one or two holes on the tilt pin.

[gazza2006au]

ok cheers mate, i freed the pin she was pretty stuck needed a bit of persuasion from a hammer

the motor actually looked trimmed in as it was, now out one hole the engine cav plate sits level with the keel i really do hope this simple fix fixes the problem as i want to get out fishing again :-?

ill give it a test run tomorrow suppose to be 27C and sunny so ill go chase some mullet for flattie and jew bait ;D

[cormorant]

consider lifting the motor as far as you can with the transom as it is. Take the cordless Just drill 2 holes , put a bit of 2x2 wood and rebolt it, do the clamps up. bit of sika as a temp fix for the holes. See where the cav plate is running when on the plane. Just check it is solid and solid on the transom

Keep a eye on the telltail and since it is new to you I assume you have looked at the impeller and pump housing as well as the tube grommet?

[Matt76]

thanks matt, i wasnt using the foot peddle for those welds just set the amp and away i went stopping to increase amp's a little at a time untill i got the alloy to melt

When you are using the foot pedal, try giving it a boot full (literally haha) at first and then once it starts melting back it off to what feels comfortable. Ally transfers heat much faster than steel so it takes a fair bit of grunt to get it started. Your off to a cracker start so keep it up mate!

[gazza2006au]

i just not long got home from testing the tinny out at our local lake and it ran beautiful i was able to turn while using full throttle without the fear of being thrown overboard, what a difference that one hole of out trim made

this little tinny rocks ;D

[Gon Fishun]

Told you that back in post 11. :hammer::lolk:

[gazza2006au]

Hell Gazza - first day out with a new unknown boat and going outside . Hope you partnered up with another boat and took the radio. Weather is just weird at the minute but can't knock it.

Wonder when the bloke replaced the gearbox and if it handled better before that one was on it yeah mate u were right, but the first day out it didnt feel as if the front was digging into to water it just felt like it was riding flat

todays test was solo so ill see tomorrow how it handles with 4 people on board

[Gon Fishun]

yeah mate u were right, but the first day out it didnt feel as if the front was digging into to water it just felt like it was riding flat

todays test was solo so ill see tomorrow how it handles with 4 people on board
That is good to hear. I had an older 15ft glass half cab with a 75 Chrysler and the first time I had it in the Caboolture river we were travelling at about 3/4 throttle and it suddenly listed to the left, for no apparent reason, and threw me to the left side. I was standing and managed to hang on to steering wheel, drag myself back and knock the throttle back. Son 27yo was sitting on the bow and WTF you doing dad. Yep scared the bejesus out of me.
The problem was loose motor mounting bolts and manual trim to far in.
Learning all the time.

[tunaticer]

The motor is at least two inches too low looking at those photos, possibly up to 4 inches. What length is the keel to the top of the transom?

[gazza2006au]

last post went out yesterday in the hawkesbury river in sydney we traveled 22km's with 3 people on board, and she ran beautiful never once felt like it was going to throw me or my passengers overboard and it topped out at 39kph for a 1970 vintage engine
i wonder what speed ill get with a new 25hp :D