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[Yogibear]

Im needing to repair one of the hulls of my MINI40 Trimaran which has been damaged.

I't been laid up for the past couple of years because of the damage but I now have some work space so want to get it repaired and back into regular use as its one of my favourite boats.

Im not really sure how to go about repairing the damage and am after some advice pointers please.

Also if its going to be a difficult job to repair is their anyone who can be recomended who may be able to carry out the repair for me.

Thanks in advance :)

[triumphjon]

id repair from the inside if at all possible , what part of the world do you live in please ?

[Yogibear]

Im up in Cumbria

Their is no way of repairing from the inside, the hull is essentially sealed with no access apart from the damaged area :(

[boatmadman]

Hi,

I think the only way to get a proper invisible repair on that is to cut an access patch in the hull to allow access from the inside.

The access hatch can be disguised afterwards, and, perhaps put an identical dummy on the other hull(s) to make it look like it was always there.

What part of Cumbria are you in?

Ian

[derekwarner]

Yogi....all is not lost   ...a sketch says a thousand words

1. cut away the damage in a manner that provides an equally sided cavity approx 140 mm long by the required width
2. prepare in install a foam former to the original hull profie ...if the weight of the foam is any concern....you could make the foam former semi hollow
3. laminate woven glass cloth over the foam & back to the prepared hull sorrunding area

If you are not comfortable with the thought of using fiber glass & laminating resin....try a fiberglass canoe/kyak repairer..... Derek

[Yogibear]

Thanks for all the replies.

Am I interpreting right that you would make a foam plug that is to the hull profile and bonded into place then fibre glass over it ???  Would balsa be as good as foam?

Im pretty good with fibre glass so dont see that being an issue.

Weight has been a concern ive had as the whole boat is very well balanced and also very light weight. Think I may have to add a little bit of ballest to rebalance it all.

[derekwarner]

  Yogi...... yes...." make a foam plug that is to the hull profile and bonded into place then fibre glass over it"

Balsa would be fine....I just thought that foam would be easier to contour.....

The suggestion from  boatmadman ....of the false hatch is well worthy of consideration.....that way you could mechanically remove the foam after the resin bonded cloth has cured & then add a little resin reinforcement internally

From the images shown the foam plug would need to be ~~~~~140 mm long ....x ~~~~90 wide.....x 80 high  & the profile of a triangular brick  with a rounded top 

........so am guessing the foam + the glass cloth + the liquid resin & hardener would not exceed 150 gms ??????????????????? & as you note you may need to redistribute or reduce ballast to compensate........Derek

[Yogibear]

Is the foam people are refering to anything special ??? or is it just like expanding foam same as used for filling wall cavities???

Im not wanting to put any kind of a hatch in to be honest as the portion of the hull will be fully submerged when the boat is up on one hull and a big factor of the boyancy is that the hull is airtight.

Been scratching my head a bit as to how I could do this with out leaving the former in and am thinking of wrapping the other hull in clingfilm and taking a mould of the damaged section from it , then laying up that section thats damaged on the mould then bonding it to the damaged hull if that makes sense.

Gonna think about it some more tonite and try and figure out where I can get supplies locally.

Oh and no it wasent me that did the damage, teaches me for letting someone else use my storage space

[derekwarner]

.....mmmmm Yogi......the foam block material you need is not polystyrene type foam... it melts or liquefies when it comes into contact with epoxy resin liquid...same with those aerosol cans of expanding foam  .....not suitable for epoxy resins

The foam you need is the type that they use for surfboard blanks here in OZ or for floation blocks that are fiberglassed into vessels.....be they runabouts or canoes or kayak's

I am sure if you can find a small sized manufacturer of fiberglass products you will find the rubbish off cuts can be bonded together to form your foam former....& the off cuts will be inexpensive too

[Yogibear]

Rite I get what you mean now, I'll see If I can track down a supplier tomorrow.

I've made molds before by wrapping the item in cling film then covering with expanding foam and doing the same with the lay up putting kitchen foil over the mold then laying up over it and the foil just peals off afterwards but stops the resins getting at the foam.

[Circlip]

Points to clarify.

  Expanded Polystyrene and Polyurethane foam is attacked/dissolved by Polyester Resins but is unaffected by Epoxy resins. So you could use it to make a former providing you're using Epoxy resin as the molding.

  You could make a plug from expanded polystyrene or urethane, laminate with epoxy and when hardened dissolve the plug out with either polystyrene resin or Acetone.


   Regards  Ian

[Circlip]

either polystyrene resin or Acetone.

   Polyester

[Yogibear]

Thanks for the continued advice.

I spent the afternoon trying to find somewhere selling epoxy based resin but everywhere round here sell Polyester based stuff.

managed to get hold of a couple of different foams and balsa but with only having Polyester based resins am going to go with the balsa wood plug.

Got the damaged area cut out and uniformed out , its a bit painful cutting into the undamaged area.

Got my daughter tomorrow so wont get to touch this before 6pm but gonna try and get the plug trimmed to shape and trial fitted hopefully.

[Yogibear]

Ok well plug is bonded in place and isent going anywhere. Made it a very tight fit anyway then applyed water proof wood glue to all surfaces.

The plug was first cut then sanded down to size and is pretty clode to the hull profile.

Ive spread filler over it which is drying currently so fingers crossed ill be able to rub it down tomorrow and get some primer on it.

Ive got a small sanding tool called a mouse which makes really light work of the sanding you just have to keep it moving back and forth quite quickly to keep the hull profile.