Designing & Building Hammerhead

[Salty Pelican]

So, we have decided to start designing and building our own passagemaker "Hammerhead"! After contemplating and discussing how to move ahead, after meeting more than a few naval architects, and after visiting many shipyards for over two years, we pulled the trigger and started the design phase!

We have set a number of parameters and goals:
- Hull lines before lay-out;
- Comfortable, efficient, and safe at sea;
- Couple operated;
- 65 feet LOA and LOW;
- Aluminium, round bilged, slender build with fine entry bow, and narrow stern;
- Single engine;
- Living, eating, cooking, and driving the boat on the same level;
- She should sleep four to six comfortably;
- Stamina, able to maintain high cruising speeds of up to 10 knots.

We hired a naval architect that seems to understand what the mss. and I want (fast displacement explorer with a focus on functionality, low running costs, that deals with various sea states relatively comfortably). Quite a relieve after discussing our plans in depth with two other architects first ... that simply felt better selling us one of their existing designs.

I'll try to inform you guys and galls on our progress. Once I figured out how to post pics, I'll share some designs as well. We are working on a Facebook page and a blog, and a website will follow in a few months.

Regards, Edwin and Veronika (currently owning Bruijs Kotter "Salty Pelican")

[ofer]

looking forward to it.

did you win the lottery?

[Salty Pelican]

No. I have been working my *ss off for the last 40 years, and with a successful international business and the kids leaving the nest, I felt it was time to invest time & money in what's become a passion: boating. With the goal to travel the world.

Ah! Succeeded to upload a profile sketch of where we are at.

[Cliff Meima]

Great idea

Here are to different boats with the same idea.

https://setsail.com/

https://www.seapiper.com/

Enjoy the build. Pleas keep posting, we will enjoy the build with you.

Cliff

[Salty Pelican]

Thanks for sharing, Cliff. The FPB, yes, that is an inspirational story. I must have seen all of their video's at least twice. The Seapiper is a nice initiative. Love small boats with big lungs! Reminds me of our current boat, "Salty Pelican".

[Blue Yonder]

Congrats. Very exciting times ahead.

No doubt you are already aware, but just in case others following may not have seen it, your mission seems well aligned to the artnautica design: https://www.artnautica.com/designs/l...nge-cruiser-58

Looking forward to the webpage. I've really enjoyed following along with the build of Mobius: https://mobius.world/

[Salty Pelican]

I love the simplicity of the LRC. Mobius looks like a great project. Thanks for sharing Blue Yonder.

[Salty Pelican]

Today, we visited KM Yachtbuilders in the north of the Netherlands. Impressive shipyard, with an impressive portfolio!

Before deciding on who we'll invite for a tender, I always like to visit a warf, just to make sure that I like what I see and that the vibes are okay.

We spoke to Euwe, the owner, and Jildou, who is responsible for sales. They showed us around, answered all our questions, and proposed we reach out to them whenever we feel they can be of assistance.

[Salty Pelican]

We consider the following lay-out:
- Lazaret in the swimming platform;
- Owners stateroom with desk, shower, and toilet in the aft section;
- Cockpit above the owners stateroom;
- Engine and tanks in the middle of the boat;
- Pilot-house (with living and galley) on top of that;
- Day-head and second shower and guest cabin forward;
- Second guest cabin / storage area near the front of the ship.

[ofer]

excuse my ignorance..

what is the cockpit used for?

[Salty Pelican]

Sit outside, drive the boat while sitting outside, doing cocktails & smoking cigars, maybe some fishing? Looking to see if we can also adapt it so that - in case of really bad weather - we can temporarily store the dinghy there. Storage in the lockers. BBQ on deck. Fav place of our dog Kifli.

[Salty Pelican]

Preliminary calculations are in and we are very happy with them! First, the design is self-righting. The GZ-curve shows values above 0 for anything from 0 to 180 degrees roll.

Secondly, the high cruising speed we aimed for seems to be achievable. She tops out at 11 knots and cruises efficiently at 10 knots.

At a speed of 10 knots, she uses 4.75 gallons per hour. Resulting in an autonomy of 4,000 Nm. Do we drop the speed to 9 knots, then the autonomy increases to 5,000 Nm.

Here is a picture of the 3D-model used in the stability modulations:

[twistedtree]

Originally Posted by Salty Pelican

Sit outside, drive the boat while sitting outside, doing cocktails & smoking cigars, maybe some fishing? Looking to see if we can also adapt it so that - in case of really bad weather - we can temporarily store the dinghy there. Storage in the lockers. BBQ on deck. Fav place of our dog Kifli.

Where is the dinghy normally stored?

[Salty Pelican]

On the swimming platform at the back, TwistedTree.

[Pete Meisinger]

I like more traditional designs, but it's your dime. (or maybe your millions)

pete

[Salty Pelican]

Originally Posted by Pete Meisinger

I like more traditional designs, but it's your dime. (or maybe your millions)

pete

Amen. To each his own. What matters is that you enjoy your boat.

[FF]

After visiting loads of offshore cruising boats , I an convinced that locating the engine room as far fwd makes the best layout.

With todays light weight diesels the engine and noisemaker weight are not hassle especially in an over 50 ft LOA

For efficiency a CCP (controllable pitch) prop will probably be chosen which mandates a thrust bearing , so a simple truck style driveshaft is inexpensive and very quiet in operation.

Locating a head & shower and perhaps Fuel filters and house battery bank behind the engine WT bulkhead creates enough barriers that simple sound proofing is all that is required.

To keep the boat in trim there might be a need to be able to move fuel or water while voyaging, depending on how light the boat is built and endurance required.

If the aft cockpit deck was low enough with 2 openings for the transom the dink could be driven part way aboard. This could provide emergency short range propulsion , or simply easy unloading of massive supplies.

[Salty Pelican]

Thanks for sharing.

The engine will be located in the middle. The ER will be soundproofed. The engine will be on ... dampers I think the word is. Forward of the engine room will be day head and shower, to further shield the the guest quarters. Behind the ER will be the owners head & shower to create more distance between ER and sleeping quarters of me and the mss.

We haven't decided on prop yet. We'll be investigating a few options. Autoprop is one of them. I don't like CCP because of the combo with a dry exhaust and the additional manual input that's needed to achieve efficiency. Efficient prop, etc. all optimized for the 10 knots cruising speed is another option we are researching. It has shown to achieve 70% overall efficiency.

Backup propulsion will probably be via battery and electric engine. Twin generator set-up to help out with providing power. Dinghy will be third backup, but strapped to the side, and with a special prop for that task.

We are currently setting the tanks up in such a way that they are close to the center of gravity. I don't like to rebalance "en route", and long, wide tanks have big surface areas, that negatively impact stability and are a pain to clean. With centralized tanks, we can minimize free surface area, make 'm easily accessible, and full/half/empty load won't impact COG.

The first design cycle shows that we still have a little bit of work to do there. Center of gravity needs to shift backwards a little bit (or we need to add some buoyancy just ahead of the COG).

To be continued ...

Regards, Edwin.

[twistedtree]

It looks to be 20m long? What the expected beam, draft, and displacement (actual weight)?


Thoughts on what engine?

[FWT]

What is the thinking behind the plumb / vertical bowstem?

And coupled with what appears to be somewhat narrow shoulders (light buoyancy) it would seem to want to dive into head seas?

Or is it just the angles shown??