DE23 / OP21(3) Questions

[Matt Gent]

Can you clarify the weight requirement? Do you mean boat + trailer are under 1100kg, or the boat should be less than that? In Germany I presume the towing restrictions and available trailers are very different than the US.

Based on my DE25 weight, I think 2400lbs is optimistic for a DE23 as it sits on the trailer. That also makes the performance estimates with 70hp optimistic. Your version without cabin would be lighter, but it may need some parts to be made in honeycomb or foam core to make the weight target as it sits on the trailer.

There are some planing outboard cruisers that are quite light, and also smaller than the DE23. B&B OB20 or Lillistone Three Brothers come to mind.

[tobi]

Weight is 1.500 kg (3.300 lbs) total trailer and boat (thats the limit of our car). In the web trailer for boats of 7 m length are about 350 to 400 kg, so the boat may have a weight of 1.100 kg (2.420 lbs). I think that the modified DE23 will be a little bit less.
I think the reason for the 70 hp engine recommended by TomW1 is not the possible topspeed but the quieter operation at 20 mph.
Anyway - I just bought the plan for the DE23 and will start planing.
Thank you very much for your input (and please excused my english, haven't used ist for a long time)!

[jacquesmm]

Correct: the boat is designed to be light but almost every builder ads "stuff" to it.
If you keep it light as designed, it will give you that speed.

[fallguy1000]

If you build it; we'd love to see a build thread or updates. None of us give a hoot about anyone speaking poor English, but we all love boats. And we all try to help if you have any troubles or questions.

[TomW1]

Matt where do you get 2400lbs as it set on the trailer. Jacques hull weight is 1500lbs. Say a few hundred more for motor and other essentials, 1800lbs. No where near 2400. Especially since he is removing the super structure and making it an open boat.

I can run them at any number you think is correct but a 70 will still be good for any weight up to 2800lbs. The new 70's are very powerful.

Tom

[Matt Gent]

The DE25 hull weight is listed as 1750lb. Mine sits with no fuel at 3600.

It appears to be built and configured to plans, with no systems on board. It does have the Armstrong bracket and glass windows, but a light engine in the middle of the recommended range. The cabin top is foam core and minimal skins.

Anchor, batteries, rigging all add up. Resin ratio doesn’t make up 1000lb.

I’d love to see other data from similar sized builds.

[BarraMan]

For what its worth my boat, which is of similar dimensions to the DE23 and has no superstructure, has a bare hull weight of 1000 kg (2200 lbs). It could be regarded as a 'heavy" build as it is built to handle a significantly higher level of performance than the DE23.

[TomW1]

tobi I think you have made a good choice. With the alternations you want to make you will have saved weight from removing the top and a 70HP motor should be fine for you as Jacques and my calculations show. Just keep the build as light as you can and don't load it heavy when you are cruising. Your build without the top shouldl weigh about 1300lbs, leaving you about 1300lbs to add motor gear and passengers, gas and everything you want to get to 2600lbs for your motor to perform as Jacques and I calculated at about 30mph at top speed allowing a nice cruise speed of 20mph. But do the math and see what you come up with how much weight you will be adding before buying the motor.

motor = Yamaha 70 = 250 do this last a Yamaha 90 is 350lbs
gas = 20 gals. = 120lbs 30 gals = 180lbs
4 passengers @ 175 = 700
miscellaneous gear and supplies and water, drinks, food = ? I always allow 400lbs, 200 for boat gear, 200 for people gear. But figure it out for yourself, once you start figuring.

So you may be at the limit of a 70HP but do your calculations and see. No need to get more motor than you need as I understand they are very expensive in Europe, from prior builders there. I would not go much over 2800-3000lbs with a 70HP though. At 3000lbs your top speed drops to 27mph and cruise at 3500rpms will drop to 19 and at 25 you will be having to hold higher rpms and guzzle gas to hold that. Prop size will range in size from 12Dx14P to 12.5Dx12P. Let me know when you get finished and I can get a better handle on prop size if you want, as it always depends on final load of the boat as you are ready to leave the dock.

Well good luck and post pictures of your build and please feel free to ask questions, there are a lot of guys that can help and Jacques is always here to help.

Regards and hope this helps you think some things through,

Tom

[BarraMan]

I don't wish to flog a dead horse, as it were, but personally I think it unlikely that you can build that boat as you have described and stay under the legal maximum towing limit for you proposed vehicle (1500 kg/3,300 lbs)!

Not a problem if you are prepared to upgrade your vehicle if necessary, but I suggest that you consider the possibility before making the investment in a boat that size. Its a BIG boat to tow on a trailer, perhaps not in USA terms but certainly in Australian terms and I suspect European terms. How do I know? Because my boat has very similar dimensions. I tow it with a vehicle that is rated to legally tow 3,500 kg / 7,700 lbs !

[fallguy1000]

I don't wish to flog a dead horse, as it were, but personally I think it unlikely that you can build that boat as you have described and stay under the legal maximum towing limit for you proposed vehicle (1500 kg/3,300 lbs)!

Not a problem if you are prepared to upgrade your vehicle if necessary, but I suggest that you consider the possibility before making the investment in a boat that size. Its a BIG boat to tow on a trailer, perhaps not in USA terms but certainly in Australian terms and I suspect European terms. How do I know? Because my boat has very similar dimensions. I tow it with a vehicle that is rated to legally tow 3,500 kg / 7,700 lbs !

He can't. He'll be buying a tow vehicle or finding a friend or slippin it.