mini speed boat transom repair

jbcurt00

Moderator
Staff member
Joined
Oct 25, 2011
Messages
24,862
Re: mini speed boat transom repair

It's a 3Gal, a little smaller then 15L (3.9+/- Gals if my math is correct) and 3L would be just under a gallon. That should run a small motor for a good bit even at WOT. Make it easy to access & refill as needed. It's an odd shape designed to sit right at the transom under the motor mount.

004156_04156-72dpi.jpg


There are other 3Gal tanks on the market:

620003lp.jpg


I think those are both Aussie approved.

iBoats.com also has 3Gal tanks available.

Whatever tank you consider make sure it's Aussie compatible....

I didn't see anything smaller then 3Gal in the quick search I did w/ google. But dig around, you may find a smaller marine tank. Although I doubt it. The only 1's smaller I've seen are the integral top mounted tanks on small 2+/- HP outboards. Those are usually only 1/2 - 1.25Gal tanks.

Is it size limitations of the under deck space or weight your most concerned about? If you could get a long narrow tank to run along under the gunnel, 1.5-2 gals (I don't have the metric equal but 10-15lbs of fuel) of fuel would probably off set the weight of the battery under the opposite side gunnel. Both could be slid forward to be just under the front edge of the 'cowl~cockpit coming'.

In the pictures it looks like there may be room to sit flat on the bottom & upright w/ your feet out under the forward cap. But I'm guessing this will be a cushion under your knees, crouched down driving position. That would move more of your body weight forward some & be easier to adjust your weight back & forth as needed while underway.
 
Last edited:

TruckDrivingFool

Lieutenant Commander
Joined
Jul 30, 2007
Messages
1,818
Re: mini speed boat transom repair

Im getting so close to rigging this thing!! i might dunk it in the water this weekend for a float test.

:D Make sure you take some pics. If you don't have her rigged by then take an oar and paddle it'll count as a boat ride.
 

Peter16

Petty Officer 3rd Class
Joined
Sep 6, 2011
Messages
78
Re: mini speed boat transom repair

thanks for the links, the issue would probably be more about weight. Right now the 15L tank fits in neatly behind my seat and infront of the splash well. However it would be great if this spot was empty so i could have somewhere to stand.

Of course i could always stash the tank up in front of my feet. My only concern is that the fuel pump on the motor may not be able to handle this?

I have been looking at go kart and lawn mower fuel tanks on ebay, Can anyone see an issue with using one of these? Provided the outlet is 5/16.

Here is the update. I threw her in the pool to see where it would float with a motor on and whether it would float at all!

make shift boat ramp was a lounge chair cushion
IMG_1219.jpg


IMG_1223.jpg


success!
IMG_1227.jpg


And I got a friend to use some muscle to retrieve her.
IMG_1231.jpg


With the equivilant of a motors worth of weight sitting on the back, the "rub rail" at the stern just touches the water surface.
 

jbcurt00

Moderator
Staff member
Joined
Oct 25, 2011
Messages
24,862
Re: mini speed boat transom repair

If anything ever goes awry, having a non-marine approved tank on-board would make for fairly sticky wicket here in the states. I suspect it would be similar down under. Great Barrier reef & all.

Looks great in the pool, nice job on ramp launch & recovery.

I think you need another float test W/ a 45lb thrust trolling motor. Just a few quick hot laps....of course pix & vid appreciated.

Does the 18hp electric start tohatsu use a pressurized fuel tank? I'm guessing not, since you ask about the fuel pump. It still uses a squeeze bulb on the fuel line? It's a siphon system, so keep the line tucked up along & under the gunnel, so that it doesn't dip & sag a time or 2, should keep from over working the fuel pump. A single gallon +/- running around basically at WOT shouldn't last so long as to burn up the pump if it is taxed.....

Given the small length & beam, have you considered adding any sort of floatation to keep the boat afloat if it were to get water in the hull? I suspect it will be very difficult to remove & reinstall the drain plug that appears to be installed.
 

Peter16

Petty Officer 3rd Class
Joined
Sep 6, 2011
Messages
78
Re: mini speed boat transom repair

If anything ever goes awry, having a non-marine approved tank on-board would make for fairly sticky wicket here in the states. I suspect it would be similar down under. Great Barrier reef & all.



Does the 18hp electric start tohatsu use a pressurized fuel tank? I'm guessing not, since you ask about the fuel pump. It still uses a squeeze bulb on the fuel line? .

Given the small length & beam, have you considered adding any sort of floatation to keep the boat afloat if it were to get water in the hull? I suspect it will be very difficult to remove & reinstall the drain plug that appears to be installed.

I suspect our coast guard equivilant is less strict as yours and although i am 1500 kilometers south of the reef i think i will play it safe and go with an approved fuel vessel.

You are correct just a standard petrol tank with an inline primer bulb. The OEM fuel hose on the tank is 7 foot long. Which is just about what i need. One would assume the motor can handle this length seeing as though Mercury/tohatsu made it.

In what instance do you think the plug will be difficult to remove? When the boats sinking and i have to unscrew it and take off onto the plane to drain the water? lol (its just a standard bung fitting you remove when your boats back on the trailer...) Since i have a battery on board i have cut an inspection port in my deck and i will be able to install an electric pump down in the "bilge"
 

jbcurt00

Moderator
Staff member
Joined
Oct 25, 2011
Messages
24,862
Re: mini speed boat transom repair

I had more of a vision of you having to lean over the transom, reach around the motor & under water to pull the plug from the outside, which would tend to compound the water flowing into the hull problem, given the small overall size of the boat. Esp since you mentioned the lack of mobility 'forced' the decision to buy an electric start motor. Quickly, and then of course getting back up onto plane...

A screw plug from the inside is probably more then sufficient. And MUCH easier to remove, if needed, while the motor is running and the boat is underway.:) Still a good idea to add a bilge pump.

I don't know exactly how to calculate the required volume & of what kind of floatation, but when the time comes, I know I can find it. Neither of the boats I purchased had any required 'oh carp' floatation, because they were built before the USCG regs went into affect. But I am going to install as much as I reasonably can under the deck, gunnels & cap.
 

Peter16

Petty Officer 3rd Class
Joined
Sep 6, 2011
Messages
78
Re: mini speed boat transom repair

Im on the tail end of rigging it now. The only thing stopping me is motor height.
I need to get a jacking plate of some sort to lift it up higher. So its a bit of a set back, i had planned to launch it on wednesday. Oh well.

IMG_1333.jpg


IMG_1331.jpg
 

Peter16

Petty Officer 3rd Class
Joined
Sep 6, 2011
Messages
78
Re: mini speed boat transom repair

a good 2".

the swivel clamps will not reach the current transom put it that way.
 

fishfeatures

Senior Chief Petty Officer
Joined
Mar 29, 2011
Messages
743
Re: mini speed boat transom repair

A quick search on the net for "homemade jack plate plans" throws up some simple ideas which only cost 40-50 bucks in materials to make.
Maybe that will help you out.
Can't wait to see it splashed , nice job it's a lovely little runabout..
 

Peter16

Petty Officer 3rd Class
Joined
Sep 6, 2011
Messages
78
Re: mini speed boat transom repair

A quick search on the net for "homemade jack plate plans" throws up some simple ideas which only cost 40-50 bucks in materials to make.
Maybe that will help you out.
Can't wait to see it splashed , nice job it's a lovely little runabout..

Thankyou so very much for this suggestion i had not even considered DIY. Most designs just use 4 pieces of 1/4" angle alloy. Simple.
 

fishfeatures

Senior Chief Petty Officer
Joined
Mar 29, 2011
Messages
743
Re: mini speed boat transom repair

Thankyou so very much for this suggestion i had not even considered DIY. Most designs just use 4 pieces of 1/4" angle alloy. Simple.

Yeah most of them seem to be foolproof ( famous last words! ) , I've actually got 4'x4' angle aluminum on order from my steel guy. I'm gonna chance making one myself if I get it done before you I'll let you know how it went and vice versa ;)
 

lckstckn2smknbrls

Lieutenant Junior Grade
Joined
Sep 18, 2008
Messages
1,114
Re: mini speed boat transom repair

Im on the tail end of rigging it now. The only thing stopping me is motor height.
I need to get a jacking plate of some sort to lift it up higher. So its a bit of a set back, i had planned to launch it on wednesday. Oh well.

IMG_1333.jpg


IMG_1331.jpg
Could you tell and add a picture of how the control and steering cables pass through the hull?
 

Peter16

Petty Officer 3rd Class
Joined
Sep 6, 2011
Messages
78
Re: mini speed boat transom repair

they just pass through an elongated hole with a rubber "Slop Stopper" in it. The UV destroys them pretty quickly so i may replace it with a stainless one.

I am going to launch it as is with out the jacking plate just so i can see how the boat sits fully laden. Then i can make adjustmeants as i see fit. Ill go for a few quick runs just to see how big a issue the motor depth is and to see how the prop performs. (75% sure it will need replacing)

rigged.jpg


you can see the tacho in this shot. The steering wheel is from the 70's. I know its ugly but it was free!
IMG_1380.jpg


front.jpg


bilge pump test
bilge.jpg
 

lakelover

Rear Admiral
Joined
Mar 26, 2003
Messages
4,386
Re: mini speed boat transom repair

Now that's what I call a bilge pump! What do you have in there?

I like the steering wheel, it fits right in the character of the boat. You could paint it pretty cheap with Rustoleum spray paint.

Great job so far, you're really coming along!
 

Peter16

Petty Officer 3rd Class
Joined
Sep 6, 2011
Messages
78
Re: mini speed boat transom repair

no bilge pump would fit under the floor so i put in a universal submersible pump typically used for sinks/showers etc.

the launch was a failure im afraid to say. The engine idles and revs fine on ear muffs. It idled ok in the water but as soon as it was under load it would cough, splutter and drop a cylinder. Im thinking electrical, maybe stator.

I put the fuel tank up front in between my legs which worked well. Im going to make up some leads and put the battery up there too.

here is a photo of it all saddled up. Didnt get any down at the ramp. wasnt worth it. ill try again soon.
careful viewers will notice my change of car. After owning 2 delightful toyotas im trying out a ford.
I dont think you Americans were blessed with the falcon ute.
IMG_1395.jpg
 

TruckDrivingFool

Lieutenant Commander
Joined
Jul 30, 2007
Messages
1,818
Re: mini speed boat transom repair

Nope no Ute for us. Sucks about the running problem but never think that we wouldn't of liked to of seen pics of the little girl floating in her natural habitat. ;)
 

Peter16

Petty Officer 3rd Class
Joined
Sep 6, 2011
Messages
78
Re: mini speed boat transom repair

I resolved the motor issue. I took it for a run and it ran smoothly. the boat porpoises wildy and leans to the left at higher speeds. i was cruising at 21knots. I will open her right up once i get the jacking plate. The water is a filthy brown colour because of all the rain we have had.

IMG_0207.jpg


IMG_0208.jpg


onthewater.png
 

jbcurt00

Moderator
Staff member
Joined
Oct 25, 2011
Messages
24,862
Re: mini speed boat transom repair

Sweet! Can you adjust the location of the gas &/or battery to remove the left lean at higher speeds? Trim tabs may help too...

Looks great in the water!
 
Top