Numerous issues to consider here. 3M 5200 is an "industry standard" - it comes in fast cure and slow cure. See here;

www.3m.com.au/3M/en_AU/company-au/all-3m-products/~/3M-Marine-Adhesive-Sealant-5200/?N=5002385+8711017+3293241623&rt=rud

The 3M Aust site does not have the TDS - see here. Suggest contact 3M Aust to get the TDS to see if it is suitable for your plastic, and to get the appropriate cleaner for the transducer and hull skin. Preparation is key.

apsafety.co.uk/images/pdf/3M%20Marine%20Adhesive%20Spec.pdf

Numerous on line forums discuss 5200 and other below the water marine adhesives / sealants. eg;

panbo.com/changing-transducers-5200-problem/

Assume the hull is single skin grp? How long do you have to allow full cure before re-launching? Some people complain that 5200 adhesive / sealant is hard to remove - would prefer this than a leak after re-launching.

If you have a foam sandwich grp hull the transducer installation is more complicated.

Of course Sikaflex have suitable similar products.

neilmac01 said..
The boat is single skin GRP - Farr 7500. However there is a gap between the FG and the sole/liner of the boat and the water ends up in the bilge. I would love to have the boat ready for the next Thursday nights twilight race, however I really would like to fix this properly. I can do this tomorrow. The boat can then sit on the trailer for another week after that. Would that work. Others suggest Sikaflex 291 or Fixtech Fix15.

ok so that's a straightforward job of re-doing the transducer installation. The sole/liner of the boat must not contact the transducer itself obviously. Both of the those products (Sikaflex 291 and Fixtech Fix15) are adhesive sealants and should do a good job - preparation and cleanliness and getting rid of all the old adhesive/sealant used being the key iaw with the product technical data sheet. Agree would do it today and let it cure on the trailer for the week.

Use FixTech sealant on my Depth Transducer and SumLog paddle and had no leaks.

Ramona said..
I have been looking for Fixtech products in the big green shed and other hardware stores but it seems it's only available at ship chandlers. I guess if it's good enough it will eventually be owned by Selleys.

The Chandlers, including Whitworths, have it at a fair price, but you won't find it in the HammerBarn. Maybe Fixtech is supporting the smaller guys. Good on 'em.

Fixtech used to be at Bunnings but ceased about 5yrs ago. Dunno why.