DE23 / OP21(3) Questions

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TomW1
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Re: DE23 / OP21(3) Questions

Post by TomW1 »

Guys, I agree with you, the aluminum trailers I looked up all weighed 1500-2000lbs, add the boat with all the gear, motor and gas over 2000lbs and his current tow vehicle cannot tow it. He needs to do some thinking on his tow vehicle or on the size of boat to build. The DE23 is great for his program but if he is not willing to change tow vehicle it is not going to be much use for him. I personally do not like to tow at the upper limit of a vehicles tow limit, I normally limit it to 3/4 of the limit. And 23' hanging off the rear end of a 14-17 feet tow vehicle takes some skill also.

Tom
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Re: DE23 / OP21(3) Questions

Post by TomTom »

What about the LB22 as an idea? Or would that be too small?

tobi
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Re: DE23 / OP21(3) Questions

Post by tobi »

Thanks for your input! It's always better to think first, than act.

A trailer with single axle rated for 1.500 kg total (3.300 lbs) has a weight of 350 kg (770 lbs), resulting in a possible boat weight of 1.120 kg (2.530 lbs). The displacement listed in the stuy plan is 1.140 kg (2.500 lbs). If you substract two people from the displacement you are about 1.000 kg (2.200 lbs) and it should theoratically fit (maybe not in reality).
Out car is a VW Touran, often used to tow caravans. But it isn't new and building a boat takes time, so it may be replaced until the boat is finished.
If I go for a double axle steel trailer and replace our car with a simillar car with a bigger engine and with 1.800 kg towing weight, the trailer would weight up to 450 kg (1.000 lbs) leaving 1.350 kg (3.000 lbs) for the boat. That would be the total max, because I would not want a car any bigger.

If I am optimistic, I would think it will work with our actuall car. If it turns out, that the boat will be heavier, a slightly bigger car with a towing weight of 1.800 kg should solve the towing prolblem.
Do you think the boat will exceed the limit of 1.350 kg (3.000 lbs)?

About the Nina: To me it is one of the most pretty designs on bateau (espacially the australian build), but it doesn't fit our programm. Even if the lenght is close it is much smaller.

Regards, Tobi

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Re: DE23 / OP21(3) Questions

Post by TomTom »

tobi wrote: Sat Feb 06, 2021 6:52 am Do you think the boat will exceed the limit of 1.350 kg (3.000 lbs)?
It takes a very disciplined builder with a clear program to resist adding more “stuff” to the build; so most boats are heavier than expected/ planned.

Also - a builder is always tempted to “add a bit more glass here and there - and maybe make fillets too big ... you know - for strength...”

I would suggest you buy the plans, look at the BOM, decide which type of plywood you are going to use and know it’s weight per sheet. With this you can calculate how much wood in the boat. Then take the total epoxy on the BOM and multiply by two/ three what it says. Then add the weight of any extra glass, and any extra structure. Add the weight of bouyancy foam, and paint. You can get a good estimate of how much you need by assuming the coverage area from the no of plywood sheets.

Then find out the weight of the things you will put in the boat...

Engine, cables, anchor, anchor rope, steering wheel, batteries, fire extinguisher, fuel and tanks etc...

This will get you pretty close to knowing what your boat will weigh.

Then so long as you don’t buy more materials you will come in about what you calculated!

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Re: DE23 / OP21(3) Questions

Post by TomW1 »

tobi wrote: Sat Feb 06, 2021 6:52 am Thanks for your input! It's always better to think first, than act.

A trailer with single axle rated for 1.500 kg total (3.300 lbs) has a weight of 350 kg (770 lbs), resulting in a possible boat weight of 1.120 kg (2.530 lbs). The displacement listed in the stuy plan is 1.140 kg (2.500 lbs). If you substract two people from the displacement you are about 1.000 kg (2.200 lbs) and it should theoratically fit (maybe not in reality).
Out car is a VW Touran, often used to tow caravans. But it isn't new and building a boat takes time, so it may be replaced until the boat is finished.
If I go for a double axle steel trailer and replace our car with a simillar car with a bigger engine and with 1.800 kg towing weight, the trailer would weight up to 450 kg (1.000 lbs) leaving 1.350 kg (3.000 lbs) for the boat. That would be the total max, because I would not want a car any bigger.

If I am optimistic, I would think it will work with our actuall car. If it turns out, that the boat will be heavier, a slightly bigger car with a towing weight of 1.800 kg should solve the towing prolblem.
Do you think the boat will exceed the limit of 1.350 kg (3.000 lbs)?

About the Nina: To me it is one of the most pretty designs on bateau (espacially the australian build), but it doesn't fit our programm. Even if the lenght is close it is much smaller.

Regards, Tobi
tobi the boat won't weigh 1350 kg (3000 lbs) without the people in it so you should be fine with the larger towing weight, don't count people weight in the towing weight, so the weight of the boat alone with motor and gear will be in the 21-2300 lb. range, depending what you put in it. You can also do what Tom-Tom suggests, but Jacques has put the hull weight at 1500 and so just add the motor and a couple hundred for gear and a few more for safety equipment, etc. that you always keep on board.

Agree with you the Nina is a nice looking boat, but it doesn't fit what you have described what you want to do.

Tom
Restored Mirror Dinghy, Bought OD18 built by CL, Westlawn School of Yacht Design courses. LT US Navy 1970-1978

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Re: DE23 / OP21(3) Questions

Post by TomTom »

TomW1 wrote: Sat Feb 06, 2021 2:28 pm Jacques has put the hull weight at 1500 and so just add the motor and a couple hundred for gear and a few more for safety equipment, etc. that you always keep on board.
I am very curious to know how many Builder’s manage to keep to the designers weights.

I am definitely not one of them - hard as I try!

I also believe - please correct me if I am wrong - that the epoxy calculation shown on the BOM is for the glass only specified. It doesn’t include fillets? Or any other glass one puts anywhere?

I am always horrified by how much more epoxy I have used - but it could just be me.

Dougster
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Re: DE23 / OP21(3) Questions

Post by Dougster »

Nope not just you. I probably use at least double :roll:

Dougster

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Re: DE23 / OP21(3) Questions

Post by TomTom »

I never found out whether these plans became available ... but this might be a contender for your criteria?

viewtopic.php?f=8&t=64118&hilit=Tina

TomW1
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Re: DE23 / OP21(3) Questions

Post by TomW1 »

Tom Tom the Tina/Nina was ruled out above. The glass in the BOM does include filets, both biaxial tape and woven tape. Dougster everyone will use more epoxy than the plans describe, but only 3-4 gallons not double :help: . He is removing a lot of the super structure from the DE23 and will be using a lot less than the plans require. :D

Tom
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Re: DE23 / OP21(3) Questions

Post by TomTom »

TomW1 wrote: Sun Feb 07, 2021 11:50 pm Tom Tom the Tina/Nina was ruled out above.
The Tina is different to the Nina - the “Tarpon Skiff” designed for Farley Boatworks. I can’t find a study plan for it.

Agree the DE23 is an obvious choice for Tobi’s use; regarding epoxy use ... if he builds it would be curious to hear how much he uses. I am certainly like Dougster - at least double 😂😂

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