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Old 16-09-2012, 02:13   #1
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10 foot fiberglass tender

Hello

A mate just gave me a 10 foot fiberglass tender.

When I attach the 4 horse Yamaha outboard with me sitting at the stern with a full 25 liter petrol tank, it seems to sit rather low at the stern. The top of the transom seems to be about 7cm above the waterline.

Any creative ideas to make the stern more buoyant ??

There is a bench seat that is attached to the transom at the top with a frontal enclosure fully fiberglassed creating a sealed air space at the stern.

The centre bench seat has an opening in the top middle where the 2 life vests and misc goodies are kept out of the elements.

The bow has a sealed seat the same as at the stern.

(I will take a picture once I put it on the hard stand on Monday)

Look forward to your ideas !!!

Alan
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Old 16-09-2012, 02:18   #2
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Re: 10 foot fiberglass tender

Use a peice of plastic pipe over the thottle handle so that you can sit in the centre of the boat
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Old 16-09-2012, 02:49   #3
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Re: 10 foot fiberglass tender

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Use a peice of plastic pipe over the thottle handle so that you can sit in the centre of the boat
+1

25 Litres is also a fair bit of fuel.
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Old 16-09-2012, 04:39   #4
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Re: 10 foot fiberglass tender

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+1

25 Litres is also a fair bit of fuel.
  • get a longer fuel lead and transfer the weight of fuel towards the bow
  • ensure that the motor is not raked outwards or it will tend to push the stern down
  • use a cavitation plate on the outboard
  • use the pipe on the throttle handle at least untill you get the boat moving
once the boat gets moveing it will tend to generate its own lift.
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Old 16-09-2012, 04:46   #5
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Re: 10 foot fiberglass tender

Yep, bit of plumbing pipe does the job. Don't have it too long or it can make it tricky to turn sharply. Moving the tank midships would also help

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Old 16-09-2012, 07:17   #6
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Hello,

Excellent feedback my friends !!

I picked up 15 feet of 5/8 fuel line and have the petrol tank at the bow. There was a very noticeable leveling, but still a very strong list to the stern.

I picked up 2 large fenders (12 inch diameter by 18 inches tall) and was thinking to play around to see if I place one on the port and starboard of the stern with a simple rope going under the tender a few centimeters forward from the transom. If that would give the added buoyancy, then I could fiberglass over the fenders (in a horizontal position) to make them permanent if it does the job.

My best mate has a small boathouse for boats up to 25 long to get the tender on land so I can do any fiberglass work I would want comfortably !!!

Alan
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Old 16-09-2012, 09:09   #7
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Re: 10 foot fiberglass tender

Others will be better on the science end of things than me (that ain't hard!) - but what you propose won't really add any worthwhile bouyancy - but will add a whole bucket of drag......I would say better off going down to 2hp, and she would likely be quicker than a 4 hp punching a couple of fenders through the water.

Basically you are not going to get more freeboard than what she has without you onboard. 4hp is not big big (for a ten foot dink), but not the smallest either. Add you, 25 litres of fuel and on a 10 foot dink no great surprise that the freeboard is low.

But I understand why you are keen to do something........7cms? (2 1/2 inches) - I would feel a little bit uncomfortable at 7 inches!..........you might be discovering why your mate gave you the dink .

No idea of course what your dink looks like - but if it is something like a Walker bay - then the common "fix" is an inflatable collar - doesn't turn her into a RIB, but nonetheless adds stability when at rest and a chance to bail her out if she does flood.
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Old 16-09-2012, 13:10   #8
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Re: 10 foot fiberglass tender

My dinghy sinks in the stern too if I don't sit toward the center of the boat. I load as much gear in the bow and put my fuel tank forward of the mid seat. I use the pvc/plastic handle method. It all works to level out the dinghy.
My engine is a 4hp Johnson 2 cycle so doesn't weigh very much which helps with trim.
Pictures might help us give you a better diagnosis.
kind regards,
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Old 16-09-2012, 13:45   #9
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Re: 10 foot fiberglass tender

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Hello,

Excellent feedback my friends !!

I picked up 15 feet of 5/8 fuel line and have the petrol tank at the bow. There was a very noticeable leveling, but still a very strong list to the stern.

I picked up 2 large fenders (12 inch diameter by 18 inches tall) and was thinking to play around to see if I place one on the port and starboard of the stern with a simple rope going under the tender a few centimeters forward from the transom. If that would give the added buoyancy, then I could fiberglass over the fenders (in a horizontal position) to make them permanent if it does the job.

My best mate has a small boathouse for boats up to 25 long to get the tender on land so I can do any fiberglass work I would want comfortably !!!

Alan
Glad moving the tank helped, have you tried the extension to the throttle handle - it will make far more difference than the tank move.
I would seriously not do what you are talking about with the fenders! As DOJ said it will add drag, not only when you have the outboard in use but also when you tow or row the boat (outboard have been know to break down). Beyond this there is the problem that they will only add to floatation when they are displacing water - the rest of the time they are only adding weight to the stern. On that subject those few extra pounds will be very noticeable when the boat is out of the water - dragging it up the beach, lifting or moving on deck. You also need to envisage the difference that the additional 2 foot width will make when the tender is on davits or stowed on deck - not good.

If you have two people in the boat and there are any waves from any direction the modifications that you are proposing will make the boat more dangerous - if you want i can explain.

What you need to do is to learn to balance your boat and work with the water rather than trying to fight it. If you want to make structural changes then you would be far better off by reducing the rocker by shortening the middle seat. While this would increase buoyancy at the stern and reduce the tendency for the boat to squirrel when been towed; it would reduce its capacity to be rowed and its total carrying capacity.

.
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Old 16-09-2012, 15:28   #10
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Hello

Great feedback gentlemen !!!

A neighbour had 8 cans of expanding foam left over from an old project he had a while back, and told me to drill a hole on the top of the stern seat and fill the cavity with the foam and seal the hole up with the fiberglass resin... Not sure about that as well.

I found a piece of 1 meter long PVC pipe that fit the throttle handle that I cut to the right length, and while sitting on the middle seat, she is level and quite fun to zip around in. The extension does not hinder any ability of turning the engine port or starboard.

I will upload a picture in the morning.

Thanks,

Alan
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Old 16-09-2012, 18:54   #11
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Re: 10 foot fiberglass tender

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Hello

Great feedback gentlemen !!!

A neighbour had 8 cans of expanding foam left over from an old project he had a while back, and told me to drill a hole on the top of the stern seat and fill the cavity with the foam and seal the hole up with the fiberglass resin... Not sure about that as well.

I found a piece of 1 meter long PVC pipe that fit the throttle handle that I cut to the right length, and while sitting on the middle seat, she is level and quite fun to zip around in. The extension does not hinder any ability of turning the engine port or starboard.

I will upload a picture in the morning.

Thanks,

Alan
Why???? if it is not broken dont fix it.
2 things to keep away from F/G , silicon and the expanding foam that you are talking about.

Again all you are doing is adding weight where you least need it. That stuff is not boat building foam.

Do some thing usefull build a bailout pump out of some 2 inch plastic pipe, a "T" peice, broken broom handle and a couple of flat bits of rubber.

Find a way to rig a mast and sail

Or just get out on the water
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Old 16-09-2012, 19:40   #12
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Re: 10 foot fiberglass tender

Aloha,
I'm glad moving to the center of the boat helped. You won't find the foam will give you any more flotation in the stern than you already have. If there is no water in the stern seat then it is providing as much flotation as it can possibly have. When you have a passenger you can seat them forward and yourself toward the stern and it should balance out the boat too.
Good luck in your experiments but don't add anything under the waterline because it will just hinder the performance of your boat.
Happy boating!
kind regards,
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Old 16-09-2012, 20:42   #13
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Re: 10 foot fiberglass tender

i had a similar problem. didn't like the idea of the pvc extension handle. but i found that if i sat down in the bottom of the boat between the rear and middle seats it solved all balancing problems. i sit on a boat cushion.
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Old 16-09-2012, 23:27   #14
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Re: 10 foot fiberglass tender

If you don't like the extension tiller, get yourself a girlfriend or large dog to sit in the front.
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Old 17-09-2012, 02:37   #15
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Re: 10 foot fiberglass tender

Hello,

I have the girlfriend but not the dog SMILE !!!

Here are a few pictures of the tender on the hard stand...

I picked up the proper "International" brand Epoxy paint for the hull and the inside. I painted the hull this morning and it was cured in 90 minutes just as the label said. I need to fix a few fiberglass cracks on the middle seat and make a new hatch cover from fiberglass (the honeycomb board covered in fiberglass mat) for the middle bench seat.

Overall it is a good little unit that just needs some TLC !

Alan







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