Next Week

 Next week 29 March

This section of my repair and Transportation blog I will update each week as we visit yards and participate in discussion

Last week we looked at the affect on timber from a metal tank that was allowed to come into contact with  timber, I would like you to think about other types of rot damage, we will discuss this and I would like you all to participate in the discussion

We talked very briefly of grounding all metals exposed to seawater used in boat construction. I would like you to think about that and do some study, we will be participating in discussion on the various methods of protecting metals underwater, both salt and freshwater, is there any difference?

If  we are able to get transport we will be visiting Gulf Harbour with a probability of being able to view metal deterioration and protection first hand. We will also look at the travelift operation, different cradle options and view the operation of a repair and maintenance yard first hand
I have booked a Van for lectures 5/4/11, 12/4/11, 3/5/11 and are wait listed next week

Last week we also talked about case studies and the best method to explain the jobs and the order they should be completed in when you do a case study. I have added to the practice case study with some notes  to assist to lay out the case studies in a workable format, you should have a look at it with a view to discussing your thoughts and questions on this in class

Those of you that haven't g mailed me how about it guys just another way to keep in contact

Next Week 5th April

We will travel to Westpark and to the TeAtatu Boating club next week. Westpark is a haulout area which is not unlike Gulf Harbour but it is a good place to see a wide range of work being undertaken we can discuss what we see on the spot, we don't have as far to travel and so we should have more time to consider the actual work. Our focus is intended to be to learn about a range of jobs and some approaches we could use to complete a repair or perform maintenance


On the way to Westpark we will stop off at Te Atatu Boating club. This is worth a look there is always interesting work being undertaken. this is more a powerboat location and there are some quite large boats hauled out on the concrete ramp on trailers which aren't roadworthy but are operational within the grounds of the club


We should also take time to catch up on what was important/interesting from the Gulf Harbour Trip I would like to do that in the form of class discussion, give it some thought and be ready to participate.


If you have any interesting pics from that trip it would be great if you sent them to me and they could be put on the Blog

We still haven't finished our discussions on some of the points from last week such as other types of Rot, and the Grounding of metals,

Next Week 12 April

The trip this week was a little bit wet and cold however we did get to view different support structures, more osmosis repair, metal protection underwater.

I did explain a little of the problems that can occur when Gel coat starts to age and the UV damage, along with the knocks that a hull takes after a few years means that its time for resurfacing the hull, a decision at that time has to be made, do we touch up the gel coat and polish the hull or is it time to repaint, I want to have a discussion on this next week, think about a paint system that could be used, it would be helpful to have an idea of the cost of the paint, we could work out a labour cost in class what other costs/problems are incurred when we paint a hull, what is the process

I thought the repair that the boatbuilder was working on was interesting, did you think the method he said he was using to join the planking was OK?

At the Te Atatu boating club hardstand  we were able to note the method which was being used to spread the load across the underside of the deck what was that?

It was also interesting to note the differences in the traditional carvel planked boats, there were several older ones with a lot of work to do and then at Westpark several examples that were excellent quality, we need to think about if you owned one of these boats what a maintenance plan might entail

I have would like to explain a method you can use to work out a labour estimate on the practice case study I will show you that next week.

We will spend next week in the theory room catching up on some of these ideas I have put forward
Other types of rot repair
Bonding of metal's for protection (difference between grounding and bonding)http://www.yachtsurvey.com/maitenance.htm
Gel coat repairs, and re paints http://iyp.yachtpaint.com/australia/default.asp
joining the planking on a timber repair
How to work out a labour cost on the practice case study

Next Week  3rd May

Hi All,
I have prepared a schedule for the remaining lectures about Maintaining Repairing and Transporting boats this should give you all an idea on the general subject area we will discuss during each session, the schedule is flexible so that if there is something in particular we need to cover or spend more time on we can do that

Repair and Transportation

Lecture subjects, (red font not yet covered)

1.      Course introduction, class introduction, Assessment description, reading material and websites. Osmosis repair, timber deterioration

2.      Osmosis repair, Timber and metal corrosion

3.      Field trip Gulf Harbour, Osmosis repair, cradle style, Trave lift operation, hardstand operation, general repair all materials, keel repair

4.      Field trip Te Atatu boat club, Westpark, Cradle style, hardstand operation, boat support systems, repair all materials, carvel construction

5.      Theory session, cost estimating, painting over Gel coat, metal protection underwater, wood deterioration (dry rot, wet rot, damp timber and metal in contact)

6.      FRP maintenance and repair, alteration, a maintenance programme for an FRP boat, Composite repair, retro fitting (composite)

7.      Field trip, slipway operation Devonport and Milford 
8.      Metal construction maintenance and repair, a maintenance programme for a metal boat, protection of metal surfaces, specific jobs for all construction types

9.      Field Trip, Dry stack operation Oram’s Marine

10.  Marine Haulage, Trailers, Boat preparation for moving, crane lifting, cradle moving, ship storage

11.  Review all lectures/subjects/assessments

12.  Review all lectures

We have completed session 5 and so on the 3rd May we will be covering the information itemised on 6 so do some thinking about work on FRP construction

Something for you to ponder, those of you that have communicated with me by gmail already have seen this suggestion
 You must do your own study which is expected to be more than twice the time that you spend at lecture sessions, we have spent 17.5 hours at lectures so far this semester, Have you completed 40 hours of your own study?
I see my role as providing a learning platform for you, therefore I invite you to start your own blog with information that we have discussed so far on field trips or class sessions, I can then see if you are on the right track, maybe you could do a blog or several blogs in groups its a great way of comparing and consolidating your own interpretation of ideas with others.

If you have another group communication you prefer that's fine maybe a google doc

Next week 24th May (two week break)

Hi All,
 We are going to go to Devonport yacht club and to Milford cruising club to have a look at how boats are hauled out using a cradle on a slipway, this means that lecture 7 will take place the following week
We can also observe a grid and discuss the purpose and relevance to today's boatbuilding, maintenance, repair

Last Tuesday we didn't finish FRP repair and maintenance and so we will do that probably in week 11

Remember if you decide to do a blog, or a google doc that can also be included in your logbook as a means of study

 






 

galvanic corrosion

Hi All,

I found this a really interesting case of corrosion and its affect on timber. This is a carvel planked hull caulked over double diagonal no glue was used in this type of construction. She is ribbed and has a solid backbone structure with sawn keel floors fastened with through fastenings of bolts and copper nails riveted. What you can see is a copper tank, what would you think has caused the timber deterioration? comment about the construction.
What is the style of cradle that supports the hull? how do you go about a repair of this type? make some notes so that we can discuss it next time

practice case study

Case study

A yacht that has been hauled out and placed in a bilge cradle needs to have its keel resealed

The boat is a 25yr old 12 metre FRP (fibre reinforced plastic) production boat

It has a moderate depth fin keel butted to a stub with single bolts fore and aft and the rest are doubles
The bolts are silicon bronze the singles are ¾ and the doubles are 1”inch there are 10 bolts in total

The keel to stub joint has been broken approximately half way from the forward end

The joint has been attached with a matrix, several layers of chop strand mat and polyester resin.

Describe the procedure to re-seal the keel

Price the repair using a Gaant chart
To find, the labour cost and the total time taken for the job to be completed
List the materials to be charged to the job

 

How do we put a repair plan into place?

List the problems that might need to be considered that could affect the outcome of the job or the efficiency of the job.

Where is the best place to do the work? Do we need it to be undercover? Is it cost effective to move it from where it is?

Do I need a support structure, a cradle, extra lifts on the travelift, or a crane?

What fittings need to be removed? Should they be crack tested in case they need replacing?

Do I have all the tools and equipment I need to do the job? Do I have all the skills or do I have to subcontract.

What is the construction and laminating schedule? Are the materials I require available immediately or do I have to order in.

How long is the job going to take? Make up a time line by listing all the jobs from prep to finishing and put a labour total of hours beside each job.

Work out a cost based on labour, materials, hardstand, and travel lift fees

 If we consider these options we could make a description for the case study that was as follows

• The Keel is supported by propping with heavy wooden props or acro proping, two on each side  
• Inside the boat keel nuts and washers are removed using a socket and socket wrench
• Care is taken not to damage the exposed bolt threads
• The length is calculated from the top of the bolt head to the lead keel and a hole saw chosen to bore down around the bolts (18mm bolts need at least 4mm clearance)
• Each bolt has a clearance hole made around it by boring down its length to the top of the lead keel with the chosen hole saw
• The hull is separated from the lead keel by lifting with the travelift, the joint may need to be forced apart with the use of steel wedges driven between the lead and the stub
• Once the joint is separated the two equal size blocks are placed between the lead and the stub and the hull rested on the blocks to keep the two surfaces apart. Wash down with fresh water
• Both faces are prepared for re-attaching by using an angle grinder to resurface, and a heat gun to dry
• A stiff epoxy glue mix is prepared and spread over the top of the lead and the stub
• The hull is lowered using the travelift and the keel aligned with the line of the rudder, the line of the mast, using a string line and level. the fore and aft bolts are partially tightened
• The bilge cradle arms are adjusted to support the hull in the correct position and the glue left to dry
• Resin is poured down around each bolt to fill the voids created by the hole saw, this is topped up as it cures
• Keel bolts are re- tightened, filling and fairing completed on the outside
• Undercoat is brushed over the joint area and antifouling applied to the same area and the boat is ready for relaunching