Sterntube

[Paulka]

I would like to hear (read!) some opinions about the following, as I have to decide what to do next.

My GRP long keeler, had a "classic" sterntube, installed 20 years ago. Unfortunately, the SS tube corroded and leaked, thus the necessity of replacing it.
I discovered in the Vetus catalog a GRP sterntube:
Great, this could solve two problems I have :
1.- obviosly, no more corrosion. ;-)
2.- I may gain the few millimeters I'm missing to install a new Kiwi prop.

Questions :
1.- Has any of the forum experts experience with the GRP sterntube?
2.- Can the said sterntube just be "laminated" (I suppose both sides of the hull) to the hull, thus eliminating all the protruding (and metalic, prone to corrosion) pieces?
3.- How much of the sterntube is needed inside the hull? That is, can it be cut just long enough to allow the gland sleeve (presumably either the "old" Halyard, or a new PSS)?

Thanks in advance for the usual excellent advices.

Paul

 

[srp]

Have a look at http://www.lancingmarine.com/ - they are really helpful, and their site has loads of downloadable pdf files of their catalogue pages. They are also a hell of a lot cheaper than Vetus:
For a 1" shaft, GRP/epoxy stern tube, for example, is £11 per 300mm, cutlass bearing £21, bronze rubber-necked stuffing box £57. All the other prices I've found have been about double that, (except for ASAP www.asapsupplies.co.uk/ - I haven't priced their stuff yet).
Not sure what you mean by
<<Can the said sterntube just be "laminated" (I suppose both sides of the hull) to the hull>>
Once you've got the old tube out (which presumably goes through the keel) you just slide the new one into place. Use biaxial glass cloth and epoxy resin. Make sure you grind the existing grp back for about 100mm all round the joint areas, removing the gel coat on the outside so you get back to the original glass. Acetone and coarse glasspaper will ensure you've got a clean dry surface to bond to.
You need enough stern tube projecting inside to clamp the rubber tube with two stainless hose clamps. You need enough projecting outside to ensure that the cutlass bearing can be fitted, removed when it's worn, and maybe located with a stainless grub screw (depends what type you buy). Best to buy it a bit over-length and cut it after it's fitted. If you do cut it to length you have to seal the cut surface with epoxy resin.

 

[boatmike]

Replacing with GRP is a good idea.
Laminate in place (using epoxy preferably as it's below WL) both sides of hull having carefully ground away the gelcoat in way of sterntube first.
Not sure of your interior layout but it will need support either at a secondary interior bulkhead or some other structure inside the boat too. So long as you achieve this you can then cut to the required length. Hope this answers your questions.