Daggerboard construction

For a long time I thought I was going to make the daggerboard in the same way as the rudder. So, with the aid of a mold. To which I have just postponed that for some reason. But at the finish of the main hull the appropriate daggerbord case slot must have been created. A good reason at last to make that daggerboard.

I made it almost according to the plans, so with a Western Red Cedar wooden core. But to prevent this core against water penetration in case of a collision with an UFO, or hitting the ground, I made two changes to the plans. First a leading edge with a high density glass fiber core behind, instead of the wood, and second a bottom part with a foam core. In addition to these changes and for structural reason I replaced the wooden core in the leading edge by a glass fiber core.

Photo’s are better than explaining by words. You can find them here.

Enjoy the animated gif of the infusion of the daggerboard.

Rudder construction is nearing completion

With the making of the steering arm the rudder construction is nearing its completion. Click here or in the photo below to open the photo gallery of the construction.

Fibreglass pivot tube for rudder case.

You can buy them and I did. However, the inside diameter is apperently slightly smaller than the outside diameter of the Iglide high performance bushes. Seems easy enough to use a reamer for the internal widening of the tube. But the tube is about 550mm long. So, a seemingly easy job turned out to become an akward job as it is only possible (for me and my tools) to use the reamer on short lenghs of tube. At the end I made the tube out of 9 shorter parts with the extra challenge to maintain a straight composite tube or how to make a seemingly simple work a complicated job 😦

Rudder construction.

After the making of the mold for the rudder blade it is not a lot of extra work to make two rudder blades, as I want an extra one in case of a fatal rudder damage. In fact, I make two complete rudder systems, one spare system in case of a fatal rudder damage.

Next is to decide which rudder system to make. Designer Ian Farrier provides various options for the rudder system.

The main choice is between the underslung rudder (not shown in the drawing) and the daggerboard style rudder. I prefer the latter as this system gives a better steering control for getting in and out shallow waters as it can be raised up and down.

The daggerboard style rudder system comes in three variations, in this drawing called A, B and C. The difference is in the manner in which the rudder blade kicks back should any object be struck.

The rudder option C with the hinged rudder box is only suitable for a steering system with cables and therefore not suitable for me because it does not fit in my chosen transmission steering system. After all, this system requires a fixed connection to the steering arm of which position is not affected by a pivoting movement.

The rudder option B is my preferred rudder system and consists of a two-piece pivoting case and sleeve. Should any object be struck or the rudderblade hits the bottom, the aluminum rudder lock bar will break, allowing the rudder to kick back preventing any more serious damage.

Rudder option A is much simpler but will not kick back should any object be struck. However, the case should split apart down the aft edge (with aluminum bolts sheering) to allow rudder blade to kick back without any damage to the transom. But some damage to the rudder case is likely to occur, which I can confirm from my own experience whith such a system on a F33. Due to the simpler construction this will become my backup and emergency system.

Click in the above picture or here for the photo gallery of the making of the rudder sleeve and case.

Finished rudder blade.

Update with some new photos about the finishing of the rudder blade in the gallery of the rudder construction.

First rudder blade half

The first two rudder blade halves are out of the mold. Click in the image above or here to see the photo gallery of the step by step process of making these blades.

Rudder mold.

In a earlier post I showed the CNC machined rudder plugs. This has since been waiting for the making of the rudder mold. Since the construction works have progressed so far that I can finish the stern now the time has come to occupy myself with the rudder assembly.

Here the still virgin stern which is now ready for the application of the rudder construction. But before I can make the rudder sleeve I need the rudderblade, for which I first have to make the rudder mold.

The goal is to make at least three rudder blades, one for me, one for Bert’s F39 and one spare. The first step is a two part high gloss paint on the rudder plug and waxing it to get a releasable surface.

Next step is adding the mold sides and my home made epoxy gel coat, consisting of a mixture of epoxy, aerosill and aluminum powder to give the mold a high density surface. In the picture above the plug is ready to receive the first layer of glass fibre laminate.

In order to give sufficient strength to the mold it is built up in the same way as the boat hull. In this picture the vacuum bagging of the foam layer …..

…. which came out quite well.

…. and being followed by the last layer of laminate ….

A very satisfactory result. More pictures are on the Fram website.

CNC milled rudder plug.

During the construction of my boat, I have gotten a lot of relationships with other boat builders, both domestically and abroad. The exchange of experiences has proved extremely valuable and is also one of the many fun incidentals of such a DIY project. Here in the Netherlands are two fellow boat builders who are both involved with CNC technology. Bert (F39) as a professional and Nico (F82SR) as a hobbyist. The fabricated parts and the mold for the daggerboard are being made by Bert​​. And just recently Nico offered to make the two rudder plug halves for my F39. Nico is an airline pilot and spent his lonely days somewhere far away in a hotel room on the programming of hundreds of lines in the CNC software for my F39 rudder. Great job Nico and thanks again.

So, as an intermediate little project, I am now working on the two by Nico’s CNC router milled rudder plugs in order to make a solid reusable rudder mold of it.

Making the daggerboard case.

The daggerboard case is made of marine plywood and I discovered the hard way (at least after two failed vacuum bags) that the porosity of the plywood makes it impossible to make an airtight seal with sealant tape onto the wood. Something to remember for all wood builders. The vacuum infusion was done with two bags, one for the infusion and one for the vacuum integrity. A stopgap and not something to copy !