Extending a Lagoon 40

[smj]

Originally Posted by Simi 60

Not a Lagoon but a Crowther Super shockwave getting extended.

Nice [emoji1303]

[Training Wheels]

^^^ what he said!

[spiv]

From CAD, I had planned to add 1.1m to the sterns, but in real life it turned out that I couldn't add more than 0.9m (3ft) or the new transom would have been too high out of the water, even though I added 60mm to the bottom of the old transoms.

I am pretty happy with the look and strength of the mod.
I will post a pic in a couple of days once I finish fairing it.

[fillintheblank]

Colin is adding sugar scope extensions to his lagoon 450. All glass a foam/honey comb, mostly for a bigger bottom step.

[Factor]

Originally Posted by Sailing August

Naval Architect & Marine Engineer weighing in here.
Such a modification would easily cost > $100k. In my opinion it is not worth the effort and cost. The custom modification will also decrease the value of your production catamaran. Save the $100k and apply it to the purchase of a different catamaran.
Catamarans are selling very quickly. Im sure your production 40' Lagoon will not stay on the market for very long. Take the sale proceeds and the additional >$100k you were going to spend and buy a newer, bigger and more optimized design. Just my humble opinion. Good luck and please keep us posted.

Originally Posted by Cheechako

This has got to be the worst case of 3 foot-itis I've ever heard of.... really?
$100k will not be enough to do this.

As I think other have pointed out, In Australia, not a place known for cheap labour and low priced work, high quality work by respected tradies is in the order of $15000 AUD for 10-12 Metre boats.

Originally Posted by Ndavies

We have a 2019 L40......Sails great. Not sure why you would ever consider this. Lagoon paid one of the best marine architects a lot of money to design this boat. But Bubba knows better???

That is like saying the worlds greatest residential architect designed my my toilet therefore it will be a great house. VPLP Designed a boat to the specs of their client, they were given a brief they met it - got paid, none of the brief I suspect mentioned light skinny and long.

[malbert73]

Exactly. Design brief of Lagoon is fit as much into given LOA as possible. Doesn’t make it fast

[EngineerRetired]

No way is it cost competitive with moving to a bigger boat.

[spiv]

Here are 2 pics of the new stern.
I swallowed the last step and created a dinghy boarding platform while adding 90cm of waterline.
All nicely faired, once sanded and painted nobody will notice the joint.
I added no width, but increased the depth at the old transoms position.
The new transoms will be about 7cm out of the water at rest and hopefully she will slip through the water easily under sail.
Will let you know in a couple of months...

[Cadence]

Originally Posted by spiv

Here are 2 pics of the new stern.
I swallowed the last step and created a dinghy boarding platform while adding 90cm of waterline.
All nicely faired, once sanded and painted nobody will notice the joint.
I added no width, but increased the depth at the old transoms position.
The new transoms will be about 7cm out of the water at rest and hopefully she will slip through the water easily under sail.
Will let you know in a couple of months...

Question, how is it tied into the hull structurally?

[Simi 60]

Originally Posted by spiv

All nicely faired, once sanded and painted nobody will notice the joint.
.

Why didn't you follow the line?

[jmh2002]

That's starting to be a more useful type of transom size for dinghy boarding, swim platform, fishing, diving, etc

I continue to be surprised at how poorly many modern catamarans are set up in this regard, with relatively small sized and poorly arranged access to the water.

It really shows a lack of appreciation by manufacturers regarding how a live aboard cruising boat is used, especially at anchor where the crew are often in and out of the water, and in and out of the dinghy, multiple times per day.

Almost everything that comes aboard over months or years of cruising comes via the dinghy and the transom - kilos and kilos of food, shopping, and supplies, all on a regular basis.

Trying to tie up and move the crew and those supplies on and off via a tiny little transom step, sometimes in a choppy anchorage, with both boats bouncing around, can be a real pita... And that's without even mentioning any of the performance or handling related aspects when underway.

But I understand why, and that for the manufacturers it's actually about minimising length, for marinas, for perceived size brackets of potential owners (who may baulk at a 50ft LOA, even if it's really a 40 something footer in volume), etc, and about creating the maximum volume within that minimised length.

Of course that is that total opposite of what makes a good multihull, which is to be long, slim, and light, relative to other factors.

[sailjumanji]

Originally Posted by Simi 60

Why didn't you follow the line?

Agree

[Factor]

Originally Posted by EngineerRetired

No way is it cost competitive with moving to a bigger boat.

Yes Way

[smj]

Originally Posted by Simi 60

Why didn't you follow the line?

Not the best picture to judge from, maybe a shot from the outside of the hull would give a better idea. Either way it has nothing to do with the function of the stern extension just the cosmetics and all that matters is whether the owner likes the looks or not.

[EngineerRetired]

Originally Posted by Simi 60

The red tie wearing muppet in the marketing department at lagoon, maybe not.

They are absolute experts at one thing, what sells boats. You know, the reason the company even exists.