Tender Feelings
by Captain Chris SchaeferDuring the refit of a 100’ motor yacht, we installed a 2500-lb. crane and an 18’ twin outboard tender on the fly bridge. We set the tender up for diving, with tank racks, boarding ladder and a decent depth sounder. During the first trip the owner took the tender for a spin, returned 20 minutes later and stated that it was a toy for the kids. He wanted something more substantial, minimum of 25’ with diesel inboard and a good dive deck. You can imagine my surprise at this.
Not only was I to get a new tender, but also depart within 14 days for Mexico for the first dive cruise off the Yucatan peninsula. Finding a suitable tender that could be delivered and then set up in the time frame proved to be a challenge—but we managed to find a 28’ open sportfish with centre console, with a 300 hp Yanmar diesel and conventional drive, delivered from the factory within a week.
Now I was confronted with the task of finding the suitable towing gear for the beast. I turned to the “experts in towing matters” and they called out a 200’ Spectra towline with a 36,000 lbs breaking strain and a shock absorber on the tender end. With a displacement of 7000 lbs for the tender, this seemed adequate for the task.
All well, we set off south for Mexico and once the lights went out we were confronted with the first problem. Just after midnight, we had a failure in the steering gear. While down in the engine room sorting out the problem, the mate came running down yelling: “the tender is on the beam and heading straight for us.” Without steering, there was little I could do so I asked him to deal with it. How he managed to avoid the collision I do not know but manage he did.
This is a problem that we have since then been confronted with again, more than once and we were not lucky every time. There are a number of scars down the topsides where the tender attacked us, usually in the wee hours of the morning.
But my biggest problem has been the towing gear. The first time, we lost the tender in 10 to 12’ slop off the Chinchorro Bank south of Cozumel. Thankfully, this happened in broad daylight and we were able to send a swimmer out to it and attach the parted towline again. Unfortunately, the designers of the sportfish seem to come straight out of the bathtub manufacturing industry. The boat, like just about any other power boat, runs well in flat, calm seas. But the moment there is more than a ripple on the water, the sportfish shows its true nature. The blunt bow does not part the waves but crashes into them, sending huge clouds of spray into the sky. Anybody on board the boat is drenched in seconds. While towing the shock-load on the gear is considerable. The towline parted when the tender decided to try to duck under a wave rather than do the sensible thing and float over it. We were traveling at about 10 knots. I have learned since then to reduce the speed even further, as slow as seven knots in conditions like these.
By the time we reached Baha California after a 4000 mile trip the tow rope was at its end. We then replaced it with a 56,000 lbs Spectra on advice of the towing experts. After another 2000 miles around Baha and up to California it was chewed out again and it became obvious then that the experts are maybe not so smart at all. The Spectra has no stretch in it at all. The entire shock-load is transferred straight onto the fibers and after some abuse, these come undone. The shock absorber they delivered was a 4’ piece of bungee cord which was painfully inadequate.
Using a 200’ multi braid nylon rope or even a three-strand rope is decidedly the better way to go. We have towed the sportfish all over the world using a multi braid line, a total of 45,000 miles and never had the towrope fail once. On one memorable trip we got caught in 45 knots or true wind in the Gulf Stream. The weather report called for 35 knots from the west and we ended up with 45 knots from the east: right on the nose. (There was an old English law that called for weather prophets to be publicly burnt at the stake. It was abolished in the early nineties: a mistake I feel). The towrope showed no sign of wear or tear after this lively ride.
The cost is substantially less than that of spectra and the entire length of the rope acts as a shock absorber. The only drawback is the bulk of the line. It is obviously much easier dealing with 200’ of ½” rope rather than 1 ¼”. But then again, who really likes to go swimming in the middle of the night for the tender when a cool looking piece of equipment fails? So when you read about the towing experts, exercise caution.
The low tech approach to towing might save you a lot of headaches and maybe even a boat. When considering towing a tender pay close attention to the hull shape. How efficient is it really, especially at low speeds, the less resistance the hull has the less loading your towline will experience.
Another consideration for towing is the drive arrangement. Towing an outboard boat, you require huge amounts of fuel on board. Diesel is the obvious choice as you fuel it directly from the mother ship. I am a firm believer in low-tech approaches especially when operating in remote areas.
A conventional drive with a reversing gear box and a shaft drive works the best for me. But how do you lock up the propeller to keep the shaft from spinning and ruining the gearbox? Derecktors of Florida have come up with the most simple shaft lock you can imagine. After looking into shaft brakes and feathering props, their design was what we settled for and it never failed. Some folks go for the messy option by filling the gear box with oil. What a pain if you want to just quickly hop in and land a fish that hooked up while you are on passage.
So if you are planning to tow a large tender do some research and give yourself enough time to find out the right approach. Develop proper procedures on how to establish the tow and how to drop the tow. Dealing with a tow can be downright dangerous when the weather turns foul. Only once the crew are thoroughly familiar with the procedures should you venture out to sea.
But let me tell you another little secret. The best kit and the best training will not do you much good if on a routine maintenance job the mechanic forgets a rag in the rocker box cover. It gets all parties involved irritated to some extent – especially when you end up waiting for the replacement engine for over two months!