Sunday, 30 July 2023

New Rig

2 Months since I posted the last modifications, I guess I am improving 🤓.
I mentioned that I would try to use my mainsail and rig that as a lugsail. And it worked! Although with some comments of my sailmaker as a lugsail needs a reinforced luff. I temporarily solved this with a Dyneema line connecting the forward ends of the yard and the boom alongside the luff limiting the tension. 

Now the sail was raised as a lug in about half a day and it looked very pretty already. 



But it took several weeks tinkering, testing and experimenting to make it a real functional lug rig. I experimented with the attachement of the halyard, the main sheet, the downhaul and a variety of other small features to keep the rig in place. And of course It had to meet a number of “Arjen”-requirements:
  • Construction as simple as possible
  • Easy to setup
  • Trimmable
  • Able to lower the mast easy and quickly without detaching downhaul, sail and halyard
  • Able to easily remove sail, yard and boom in one package for dry storing
Short test
I took Narhval for a sort test on a nice 3 BFT day on the local canal (Van Harinxmakanaal) and I found it sailing surprisingly well! Easy, relaxed and comfortable without any noticeable compromise to the sailing characteristics. It even tacked easier and it seemed to be a bit more controllable as well. Of course this due to the shifted CE which worked as I hoped for. 

Mizzen
Although the boat sailed better balanced it stil seemed to be a bit leeward and that was what I hoped for too. I got courages and decided to implement a mizzen as well. I considered a few options for this sail and came up with a triangular spritsail. This sail is very easy and fast to fold down to the mast, it doesn’t require a long stern sprit and it lacks yard and boom. It also is trimmable with the tension of the sprit. I made it so that I only have to detach the sprit tensioner to be able to pull out the mast-sail-sprit-pack in an instant. 

Probably I have to trim the mainsail a bit forward now but as the weather here in the Netherlands has been “reset” to 5-6BFT and rainy I wasn’t able to test it in the current configuration yet.






One of the things I learned up till now is that the calculation of CLR and CE isn’t as easy and straightforward as it seems. Especially the CLR needs some reconsideration. I found lots of information on the internet usually calculating the lateral surface under water as a whole finding the CLR.
As the shape of the bow influences the frontal resistance the shape of the lateral resistance must have a similar effect too. More about that in a next post.
 

Sunday, 14 May 2023

Minor and major changes (less is more)

In a previous post I already told that “tinkering” is at least as important as sailing. Probably the sailing is instrumental to the tinkering. How else would I know what to tinker 😇.

First of all I would like to get rid of the boom gallows. It is a lot of structure used in a small spot of the boat. In the Netherlands a kind of removable support (called mik or schaar) is more common and in a aluminum boat that is easy to make. In addition I had to install an extra line to keep the boom up during rigging (couldn’t find the right English word).




So, nice light weather, time for a test and I wished that I didn’t invite Elsa because it didn’t go very well. The main sheet got tangled in the aft clamps and the jib sheet ditto around the air scoops. Now the the tangling jib sheets bothered me every trip so that had to be “cured”. The main sheet problem was solved quite easy. And again aluminum is a bless: an angle grinder and a welding machine dit the job in no time.





Cut from the rim of the cockpit and placed in inside! A even more “clean” lay out. I guess my boat becomes a real prototype?

Now another issue was the foot rail on the roof of the cabin. That was a bit to low to be really functional. At the broadest beam it would have been nice to be able to tie a fender to it as well. So that was my next project. 








Oh I forgot to mention that up until now I was able to re-use parts and use scrap aluminum to make these changes.
I also realise that with all these (and previous) changes I definitely need a major paint job. But as aluminum is “gentile” on corrosion that can wait till next winter.

Now for the major changes…
That jib… During my sailing training weeks (in the pre-history) I always hated the jib the most. Rigging it on a small fore deck on restless Frisian lakes always flapping aggressively and now tangling its sheets around my air scoops. Would be nice to get rid of that sail as well. And so I began to study an old love again: the lug rig! Could it be possible to make a lug rig on my Pocketship?

Of course it is possible. Even on the CLC website there is information to be found for a lug rig on the Pocketship. But how to make that from the existing rig? With a bit of (real scissor) cut and paste I got the idea to make it simply of my mail sail including boom and gaff. I also saw that it would be possible to trim it forward and aft depending on the attachment points of the halyard and the downhaul. 




Probably it will enable implementation a mizzen as well. First of all I want to have it trimmed as a single sail. Later on I can shift this sail more forward to have it balanced with a mizzen. 

And of course there needs to be some Arjen-invention-input as well. So I figured out how to make this setup so that I can rig it easily and can lower the mast instantly (for the many bridges in Friesland) But I will post later on that topic.

Friday, 3 February 2023

More of a builder than a sailor

Maybe I promised to have some more footage of being on the water with the Narhwal. I have to read the earlier posts to confirm that 😉.

In the mean time I can bring up lots of excuses why I havent been on the water more often. I guess cold feet is one of them, however I also discovered that I am more of a builder than a sailor. 



In the past few months I considered all kinds of building plans: From building a new boat from scratch to restoring an old ship and, to modify my Pocketship.


Findings that need modification 😇

Although I wasn't as much as possible on the water I sailed enough to get to know my ship better.

I discovered (as most Pocketship owners did) that the boat can be a bit leeward. The common applied solution is to trim the mast a bit back wich in my opinion doesn't effect much. 

Secondly, and that is a common Pocketship characteristic as well, is that the Pocketship has a relative slow turn rate for such a small vessel. In close hauled courses after tacking it is recomended not to tension the jib to fast as the boat slows down considerable and the rudder effectivity is decreasing. Adding up to the leeward tendency it is a bit tricky to keep the boat close hauled after tacking. I found out that in Strong winds (6 Bft) the effect is even worse loosing control completely bearing away up until a broad reach.

Now for the slow turn rate I guess the model of the rudder is one of the culprits. Of course it fits esthetically the nice classic lines and it ommits the necessity of a complex tilting mechanism.

Another reasson for the slow turning probably is the long keel streching over almost the entire lenght of the hull. Now the keel was an eyesore allready for a longer time and for several reassons: First off all it causes some trailer issues. As most standard trailers can accept V-shaped hulls, when it comes to even a shallow keel, the trailers have to be modified. I did a lot of tinkering to my trailer and even modified the front of the keel to be able to get the boat on the trailer smooth and easy.




Furthermore the keel also makes the boat sit quite high on the trailer but the most important issue is that you can't keep the Pocketship level easily if you beach the boat or fall dry on the Wadden.


The Pocketship showing this on the right is built by Bruno Lequeu of Dijon, France.

Now as expected my aluminum Pocketship is some heavier than the original wood-epoxy version. Therefore it sits about 1/2 to 1 inch deeper in the water which is negligible in the water. On the trailer however it can make a difference. But getting out the leas ballast can be quite an operation. So all in all I need to get rid of that keel someday 😑.







First major modification (plan)

The theory of reducing leeuwardness is simple: Either move the center of effortness (CE) backwards or the center of lateral resistance (CLR) forward (or both ofcourse). Moving the CE backwards means that the center of the complete sail-area backwards. When a boat is trimmed well, this can be done by minor shifts of the mast. My approach is a bit differtent: I want to shorten my mainsail by cutting a part of the leech and shorten the boom. Than add a small (unstayed) mizzen (see picture below).
Execpt from moving the CE backwards this way I also attain some more directional control.

Although not stricly necessary I also want to remove the boomgallows. It doesn't serve a purpose for catching the boom anymore and only for lowering the mast for trailering I make a removeable support, either apart or in combination with a divisible mizzen-mast.

Also the layout of the main sheet will change. The standard layout tends to "entanglement" either with other lines or with myself. So I want to implement one attachpoint on the boom probably with some tension divider.


After this modification I want to sail it a bit more frequent. The second major modification (plan) I will implement in 2024 so that I can tweak the plan with the latest experience. This will consist of trimming the keel, change the centerboard (longer and narrower) and change the rudder.