Anyone have/had a Nautitech 40?

[BeOur3rd]

fill me in on how bad/good was your experience with it!

[BeOur3rd]

or even nautitech in general? anyone?

[ejlindahl]

I saw a ~15 year old ~44' one in a Portland boat yard drying out for a year with the hull gel coat all peeled off. Don't know how it ended up. Get a surveyor who knows how to use a moisture meter.

[chris in SG]

I have a 10 year old Nautitech 40, 3 cabin version, which was chartered for 8 years in Spain by the previous owner before I had her shipped to Singapore. Since then, I've done a number of upgrades to suit my preferences. I've also discovered most of the weaknesses of the construction. As for the design, there's no point making this another debate about the pros and cons of exposed helms..

Let me know if you prefer private or public discussion...

[SVNeko]

There is one here in Samana DR. It looks like someone chopped the aft third of it off.

[BeOur3rd]

Originally Posted by chris in SG

I have a 10 year old Nautitech 40, 3 cabin version, which was chartered for 8 years in Spain by the previous owner before I had her shipped to Singapore. Since then, I've done a number of upgrades to suit my preferences. I've also discovered most of the weaknesses of the construction. As for the design, there's no point making this another debate about the pros and cons of exposed helms..

Let me know if you prefer private or public discussion...

i believe in being open, why not? information might as well be there for everyone to grab!

[chris in SG]

Here's a series of photos showing an example of possible alterations that can be made to suit personal preference. Some people might query the wisdom of cutting a full height door frame in a structural bulkhead but I was able to compare with the starboard hull (on this owner's version) where the shower compartment door is the same size through the same bulkhead.

The configuration keeps a single bunk (fore and aft) with storage and washing machine underneath. The basin is partly for utility and partly for testing of desal water. Through the door is a small workshop with bench, vice, etc.

N40 owners will recognize that the new basin surround was stolen from the port heads.

[chris in SG]

Apologies, attachments now I hope..

[Iaangus]

I like what you have done Chris, You are now able to utilize your space so much better than just piling supplies on a bed and you still have a single bunk.

[spiv]

Originally Posted by chris in SG

..... I've also discovered most of the weaknesses of the construction.
Let me know if you prefer private or public discussion...

Hi Chris,

can you post pictures of the bridgedeck?
Can you tell us what the bridgedeck clearance is (real measurement...)
Do you have pictures of the boat out of the water?

Do the flat portion produce noise/ slamming when underway?

Do you find that the furniture and other interior wood fittings screach or make noises when underway and the boat flexes?
I had a Salina and there was quite a lot of noise.

Thank you!

[chris in SG]

Originally Posted by spiv

Hi Chris,

can you post pictures of the bridgedeck?
Can you tell us what the bridgedeck clearance is (real measurement...)
Do you have pictures of the boat out of the water?

Do the flat portion produce noise/ slamming when underway?

Do you find that the furniture and other interior wood fittings screach or make noises when underway and the boat flexes?
I had a Salina and there was quite a lot of noise.

Thank you!

Here's a photo, taken from port transom step. The main central portion of the bridgedeck has a clearance of 24", loaded for liveaboard. That seems very reasonable to me. It passes the test of being able to manoevre the dinghy underneath. However, you can see that the downside of having relatively narrow hulls is that the bunk space intrudes under the bridgedeck by about 24" towards the centerline, and for this portion the bridgedeck clearance is reduced to 18".

I have only experienced slamming under the bridgedeck in confused water, like intersecting ship wakes and so forth, where the waves sit up in a random manner. I've not crossed an ocean (yet) so I can only speculate, and hope, that clearance is adequate for the longer period open sea conditions. I can say, more confidently, that I've not experienced any 'creaking and groaning' when underway.

Putting this reply together has made me realize how I regret the recent loss of both phone and laptop at an airport, together with all photos of haul-outs. Still trying to retrieve files from elsewhere..

Happy to answer further questions if I can!

[spiv]

Thank you Chris,

good to hear that you haven't experienced slamming. I struggled not to add the word 'yet' at the end, I will try and explain my reasoning below.

I had a lightweight 12.5m (41') cat and it was ok most times, BUT when in big seas it would slam to the point that things would fly off the table and most people could not sleep in the bunks; clearance 26"

My Salina also would be ok most of the times, but when on passages, it would occasionally slam + moan and groan, nothing structural, just furniture rubbing against the fiberglass. Lenght 14.3m (47') clearance 34".

This article from Multihull Dynamics, is the most comprehensive I have found on the subject.
In short it concludes that bridgedeck clearance should be at least 30" on a 40' cat.
And in my experience and the ones of many cruisers I spoke to, he is correct.

Other issues to consider on any smaller, production roomaran are: displacement, coefficient of finesse, hull beam and more.

I am looking at buying a 38~40' roomaran and modify it to make it better at sea.
Hence my interest in the Nautitech 40, looks appealing to me and the inside finish is also nice.
Lengthening bows and sterns will fix most of the problems, but it would do little with bridgedeck clearance, perhaps 2".

Have you finished your mods?
What are your plan with your boat?

[chris in SG]

Originally Posted by spiv

Thank you Chris,

good to hear that you haven't experienced slamming. I struggled not to add the word 'yet' at the end, I will try and explain my reasoning below.

I had a lightweight 12.5m (41') cat and it was ok most times, BUT when in big seas it would slam to the point that things would fly off the table and most people could not sleep in the bunks; clearance 26"

My Salina also would be ok most of the times, but when on passages, it would occasionally slam + moan and groan, nothing structural, just furniture rubbing against the fiberglass. Lenght 14.3m (47') clearance 34".

This article from Multihull Dynamics, is the most comprehensive I have found on the subject.
In short it concludes that bridgedeck clearance should be at least 30" on a 40' cat.
And in my experience and the ones of many cruisers I spoke to, he is correct.

Other issues to consider on any smaller, production roomaran are: displacement, coefficient of finesse, hull beam and more.

I am looking at buying a 38~40' roomaran and modify it to make it better at sea.
Hence my interest in the Nautitech 40, looks appealing to me and the inside finish is also nice.
Lengthening bows and sterns will fix most of the problems, but it would do little with bridgedeck clearance, perhaps 2".

Have you finished your mods?
What are your plan with your boat?

Very interesting Stephano, thank you. I was initially puzzled by the data plotted by multihull dynamics. The Nautitech 40 has been criticized for a number of reasons, but generally not as a result of poor bridgedeck clearance (relative to similar sized cats) so I wanted to investigate. It seems that it is all about loading (predictably perhaps). I'm attaching a side view of the N40, from the builder's manual. Not super-accurate, but adequate. The design waterline is at the lower 'black' portion, showing healthy 'daylight' under the transom. This cross-checks with the stated draught of 1.20m, when I scaled this off. However, my current waterline is just touching the bottom of the transom which, by chance, coincides with the bottom of the upper black band on the drawing. This is a difference of a massive 8", suggesting that if Nautitech had quoted a bridgedeck clearance (they never did) it would have been 32" instead of 24". This would place the N40 a little better than average when compared to the other designs considered by Multihull Dynamics.

Of course, I'm assuming that MD used published data or measured off similar drawings of unloaded waterline in all cases.

So I'm no longer puzzled about the 24" measurement but the real issue, of course, is finding sufficient clearance when realistically loaded. The N40 is sensitive to load, being relatively low displacement (light displacement 7,300kg). I concentrate on keeping the transoms out of the water, but can only do this with half tanks of water and fuel (total tankage of 600litres of water and 300litres of fuel is generous, so the difference between empty and full is almost 1 metric ton).

From Stephano's point of view, the same argument can be used to promote the N40 as a good 'project' for lightening. If you set out to return the boat to its design lines, you will recover much more than 2" in clearance.

As for my plans, since you asked, I'm currently working on converting saloon seating space into a forward facing nav station, since the standard layout is designed for a charter party of a dozen sitting down to eat! I will post some photos shortly. From the new nav station, it will be possible to keep watch sheltered from sun and rain, with largely better visibility than at the helm, though only with autopilot of course. I enjoy the twin helms immensely, but not all the time..

Future cruising is likely to be limited to South East Asia, where I believe the N40 will be ideal.

[spiv]

I am sure you'll enjoy cruising on her!
Since you are still in 'renovation mode' you could regain some buoyancy and get more waterline length by extending the sterns as many Seawind 1000 and other cats owners have done quite successfully.

[chris in SG]

Originally Posted by spiv

I am sure you'll enjoy cruising on her!
Since you are still in 'renovation mode' you could regain some buoyancy and get more waterline length by extending the sterns as many Seawind 1000 and other cats owners have done quite successfully.

If I'd had your advice 3 years ago, when I opted to paint the hull silver, I think I would have done some extension at the stern, particularly as I'm not expecting to be paying berthing fees 'by the foot' in future. It might be difficult to justify now, particularly as I chose Awlgrip which can't be touched-in.