Determining if your boat’s swim platform can safely carry the combined weight of the lift and tender/jet ski is crucial but does not anticipate you will readily find a simple, general answer. Here are some steps you can take to assess the platform’s suitability:
1. Consult with the boat manufacturer:
- Ask your boat dealer or manufacturer whether the existing platform can safely support the combined weight of the lift and your tender/jet ski. It can be difficult to get a definitive answer, for older boats.
2. Practical Test:
- Lift the boat onto a hardstand and gradually and carefully load the platform with “ballast”, e.g. lead ingots of known weight.
- Calculate the total ‘working weight’ of your tender (include outboard motor, battery, etc.), add the lift’s weight (about 80 kg), and then start adding ballast weights to the platform.
- Watch for signs of flexing in the transom or the supporting brackets. If you notice even the slightest flexing, in either, stop immediately. You will need stronger supports for the swim platform and possibly have to strengthen the transom.
3. Strengthening Supporting Brackets Under Swim Platform
- New, stronger brackets can be fitted between the transom and the underside of the swim platform. Images 3, 4 and 5 below show the two stronger stainless-steel brackets fitted to a Grand Banks 42 Classic. The two original outboard brackets (made from bronze tubing) were left in place, one of which can be seen in Image 4.
The new brackets were designed to fit onto the original through-transom bolts. This minimized drilling new holes in the transom under the waterline and avoided any ‘retrofit’ appearance.
Most marine engineering shop can fabricate and install suitable stainless-steel brackets.
3. Strengthening the Transom:
- If flexing of the transom is evident, you may need to strengthen it internally, using fiberglass, aluminum, or stainless-steel gussets tied between the transom and a hull stringer. Image 6 below shows the preliminary work being undertaken on a Grand Banks 42 Classic. This process is not difficult or expensive and can be done by a competent boat builder or marine engineering shop.
- If the swim platform is an integral part of the boat’s structure (i.e., no separate brackets underneath), the need for additional transom strengthening is less likely. However, it’s still prudent to check with the boat manufacturer.
This approach will help ensure that the combined weight of the lift and tender does not negatively affect the structural integrity of your boat.
IMPORTANT INFORMATION
Please ensure you read the answer to FAQ 5: ‘What Warranty Is Provided with Prestomarine Lifts?”
It is the purchaser’s responsibility, to properly and safely cradle and secure whatever dinghy, tender, jet ski, or anything else placed on and/or lifted by the lift system. The manufacturer, Prestomarine Lifts shall not be responsible for any damage to your boat, tender, jet ski or anything else placed on, and/or lifted by the lift system – see details of the Warranty on page 2 of: CrestMarine Australia Order Form 2025.
As the purchaser of the lift, it is your responsibility to properly and safely cradle and secure the dinghy, tender, jet ski, or any other items placed on or lifted by the system. The manufacturer, Prestomarine Lifts, is not responsible for any damage to your boat, tender, jet ski, or any other equipment placed on or lifted by the system.