Fixing up an old Bontwitco With 400c

[NickC73]

Hi all,

I'm hoping someone here might be able to give me the benefit of their wisdom about the Bonwitco 400c. I recently bought one off eBay and she needs a bit of TLC! Here's a photo of her:



One of the (many) tasks that I need to take care of is replacing the old seats and seat posts. Unfortunately, most of the bolts fixing the seat posts to the floor sheared off as I was trying to undo them. I've managed to get one seat post removed by the other is refusing to budge. The base itself is broken, but what remains seems to have been stuck down with mastic as well as the bolts. My question is this - what are the seat posts bolted into? You can see a raised square under the GRP which I'm guessing is a block of wood? Does anyone know how thick it is?




When I fit the new seat posts I'm not going to be able to use the existing bolt holes in the floor as the sheared off bolts are still in there, so I'll have to screw them in, but I don't want to use anything that's going to go too far in and pierce something it shouldn't! Or, does anyone have any better suggestions for fixing in the new seat posts?

Secondly, the top of the cuddy (and elsewhere in fact) is covered in a really solid layer of black deposits - like mould or mildew. It seems incredibly resistant to the my jet wash even at close range. I've tried rubbing it off with some wire wool with water and that seems to do the job, but I'm left with a dark stain afterwards. Does anyone have any advice on how best to remove this and restore the colour back to how it would have been before? You can see it quite clearly in this photo:



One final thing - the windows have soaked up more than their fair share of UV and are totally buggered. Does anyone know where I could source replacement windows and seals from please?

Sorry for all the questions, but I hope someone can help!

 

[Muddy Boat]

All sorts of ways to attach seat base, I would get the old one off and see how much damage you have to do and then plan around that.

Black Deposit - If mildew then bleach solution or patio cleaner.

Windows - Loads of threads on these. Buy relevant thickness of Acrylic ready cut or to cut yourself, readily available. New rubbers from someone like reddiseals.

Good Luck

 

[duncan99210]

Seat base: remove, by drilling out old fixings if required and have a look at the base it's fixed to. As you say, likely to be a bit of plywood glassed onto the deck. Easy enough to turn new base through a few degrees and fix into a new area of the pad. Given that you probably have no access to the underside of the deck I'd use hefty wood screws or self tappers to fix it in place. Seal the holes from the old screws with sealent before putting the new base in place to prevent rot.

Nasty black grot. Don't use ordinary wire wool: it'll shed bits which will rust and you'll have real fun getting the bits out. If the grot is fairly thick but shifting with effort, then you could use those stainless steel scourer pads you use for cleaning pans: as good as wire wool but they don't leave rusty bits behind. However, if the black isn't shifting and bleach doesn't work, try oxalyic acid. Brush on, leave for 10-15 minutes, rinse and repeat. Can't do any harm but might well shift it. Take the usual precautions when handling the acid. (You can buy the powder of eBay). If that doesn't work, try brick acid...
Windows. As muddy boat says, do a google search on replacing boat windows and you should get links to the threads in here. It's a case of getting your own acrylic cute shape, sourcing seals and fitting them.

 

[NickC73]

Thanks for the replies gents. I'll let you know how I get on. Have a few hour free on Saturday, so I'm going to see if I can shift that old seat post (and hopefully not cause too much damage in the process!).

 

[Spirit (of Glenans)]

All sorts of ways to attach seat base, I would get the old one off and see how much damage you have to do and then plan around that.

Black Deposit - If mildew then bleach solution or patio cleaner.

Windows - New rubbers from someone like reddiseals.

When I refurbished a Leisure 17, many years ago, I got the window seals from a local motor factors which specialised in supplies for coachbuilders and commercial vehicles. There is a special tool , similar to a screwdriver with a diamond-shaped loop at the tip, which will make it a lot easier to get the silver plastic insert in. Fix the seal in place with a suitable sealant, not forgetting to cut it a little oversize, maybe 12 mm, whatever you can squeeze in by trial and error, as it will shrink fairly quickly.
To get the acrylic in, you first put twine into the slot, all the way round, and overlapping at the end, then get someone to hold the acrylic tightly up against the seal, (a rugby prop is useful here ), while you slowly pull the twine out, perpendicular to the acrylic and seal, in order to get the lip to go over the acrylic.
Be careful to match the slot in the seal to the thickness of the acrylic. Don't ask how I know this

 

[NickC73]

Hi guys,

Just thought I'd give you a quick update. I've struggled to get much time to work on the boat but yesterday I finally got almost a whole day to get some stuff done.

I really wanted to see if I could shift the green / black mould build up. You may recall she was covered in it:





Well, I tried all sorts, but the thing that really worked was this stuff:

https://www.sheridanmarine.com/product/formula-one-cleaner-degreaser

I squirted it on, left it to soak in for a bit, gently worked it in a bit with a scrubbing brush, then blasted the shit out of it with my jet wash! The results are pretty amazing...





I had tried the jet wash before, but it didn't really shift it, so the Formula One stuff really did the job.

So many jobs to do on this boat, but at least she looks a bit tidier now!

I'll post more photos as and when I get stuff done.

 

[<152587>]

Have a word with Martin Wills at Willsmarine, Kingsbridge, his father made them.

 

[NickC73]

Thanks for the tip - I spoke to Martin this morning. He was involved in making them too with his father. I told me that there's a square of 1/2" ply glassed into the deck. If I can find good fixings, I'll be able to fix with some fat self tapping screws.