Engine Weight Capacity for a Whaler Drive on 22-foot Hull

[Jcomeau0]

[This topic is moved to the GAM because it seeks information or specification data on a classic-era Boston Whaler boat--Moderator]

Q1: does a Whaler Drive have a limit on the engine weight?

Q2: what is your opinion of having a total engine weight of 932-lbs on the Whaler Drive for a 22-foot hull?


BACKSTORY
On my 1988 Revenge 22 W-T Whaler Drive, I will be replacing the older twin Johnson 120-HP engines with twin 2002 Yamaha 150-HP HPDI engine. The new engines will be considerably heavier than the old engines. I believe the new engines each weigh about 466-lbs, so the total engine weight on the Whaler Drive will be 932-lbs.

I have [read] speculation online about [the possibility of having] too much weight on the Whaler Drive, especially while trailering.

Also, I have seen boats with a Whaler Drive that have engines that are larger [than something].

[mattmapple]

The weight limit for Whaler Drive is 700 to 800-lbs.

Having 932-lbs on a Whaler Drive might be a bit [too] much--especially for trailering.

Check with a Boston Whaler expert before installing the new engines.

Also, heavier engines could affect performance and safety.

[jimh]

The weight limit for Whaler Drive is 700 to 800-lbs.

Please give a link to where you found that specification published by Boston Whaler.

[jimh]

Q1: does a Whaler Drive have a limit on the engine weight?

I have not seen any published specification from Boston Whaler about a limit for engine weight on a Whaler Drive, which is probably because in the manufacturing epoch when the Whaler Drive was offered Boston Whaler never gave any formal statement of a maximum engine weight for any boats.

About the only way to infer what might be a limit on weight is to look at the engine power rating for the boat and then to consider a set of twin engines which would create the maximum power rating would have weighed when the boat was built.

For example, on the REVENGE 22 W-T Whaler Drive the maximum power rating was 240-HP in the 1986 and 1987 model years, then increased to 450-HP in 1988 and 1989 model years, and then reduced to 300-HP in 1990 and following years.

Using the 240-HP rating as the most conservative, the engines would need to be twin 120-HP. In that category an OMC 120-HP engine would have weighed 370-lbs. From that an inference could be made for an engine transom weight limit of 740-lbs.

Using the 450-HP rating as the least conservative, the engines would be twin 225-HP. In that category an OMC V6 225-HP engine would have 480-lbs. From that an inference could be made for an engine transom weight limit of about 960-lbs.

Using the 300-HP rating, the engines would have been twin 150-HP, In that category an OMC V6 150-HP engine would have been 402-lbs. From that an inference could be made for an engine transom weight limit of 804-lbs.

So you perhaps can pick and choose which weight you think is most appropriate.

I have seen a Whaler Drive rigged with twin V6 engines that were apparently quite heavy, as the water line at the Whaler Drive was noticeably much higher than what I see on my single-engine Whaler Drive. In my REFERENCE article on the 22-foot hull there are two illustrations that clearly show the static water line on a 22-foot hull with Whaler Drive, one with a single engine and the other with twin engines. From the article at

https://continuouswave.com/whaler/reference/22Outrage/


FIg.1. OUTRAGE 22 CUDDY Whaler Drive rigged with twin large V6 engines; note static water line at the Whaler Drive.


Fig. 2. REVENGE 22 W-T Whaler Drive rigged with single V6 engine; note static water line at the Whaler Drive in comparison to Figure 1.

ASIDE: for all twin engine installation an additional support bar was necessary which connected the hull transom to the Whaler Drive transom on the centerline of the transom. Typically the hull and the Whaler Drive were fabricated with the necessary holes already made, but covered by small circular plates. The selling dealer that would rig the boat would install the added upper support tube if the boat was getting rigged with twin engines.

[jimh]

Q2: what is your opinion of having a total engine weight of 932-lbs on the Whaler Drive for a 22-foot hull?

Depending on which engine maximum power rating was associated with your particular boat (which varied by model year) a total engine of weight of 932-lbs might be considered to be appropriate on the basis of two engines of the appropriate power that were available to be rigged on a REVENGE 22 W-T Whaler Drive boat of that model year would have weighed.

Regarding hauling the boat on a trailer on the highway with total engine weight at the inferred maximum permitted, if long distance towing of the boat on the trailer on the highway were anticipated, or if the boat would spend a great deal of time when not in use on the trailer, I would seriously consider having a specialized trailer fabricated so that in some clever manner incorporated into the trailer the Whaler Drive could be supported by the trailer frame and not left cantilevered out from the hull and unsupported.

At first glance at that problem, it seems that a float-on trailer as opposed to any sort of trailer where the boat is pulled forward onto the trailer would probably be the best approach. Another alternative would be a trailer loading which was done without using the conventional sloping ramp, such as overhead slings.

I know using overhead slings and a TravelLift might sound very odd, but I encountered such a set-up at a large marina in the Pacific Northwest in La Conner, Washington. There trailered boats were lifted off their trailer by an overhead sling and then moved to a haul-out berth and lowered into the water. This arrangement was used due to a large height difference between high-tide and low-tide. It also was useful in keep the boat trailer out of saltwater. The local boat trailers all had gaps in the trailer bunks where the sling could be passed through to facilitate being lifted off or put on the trailer bunks.